Depletion of tropospheric ozone associated with mineral dust outbreaks

From May to September 2012, ozone reductions associated with 15 Saharan dust outbreaks which occurred between May to September 2012 have been evaluated. The campaign was performed at a mountain station located near the eastern coast of the Iberian Peninsula. The study has two main goals: firstly, to analyze the decreasing gradient of ozone concentration during the course of the Saharan episodes. These gradients vary from 0.2 to 0.6 ppb h(-1) with an average value of 0.39 ppb h(-1). The negative correlation between ozone and coarse particles occurs almost simultaneously. Moreover, although the concentration of coarse particles remained high throughout the episode, the time series shows the saturation of the ozone loss. The highest ozone depletion has been obtained during the last hours of the day, from 18:00 to 23:00 UTC. Outbreaks registered during this campaign have been more intense in this time slot. The second objective is to establish from which coarse particle concentration a significant ozone depletion can be observed and to quantify this reduction. In this regard, it has been confirmed that when the hourly particle concentration recorded during the Saharan dust outbreaks is above the hourly particle median values (N > N-median), the ozone concentration reduction obtained is statistically significant. An average ozone reduction of 5.5 % during Saharan events has been recorded. In certain cases, this percentage can reach values of higher than 15 %.

Gadolinium-DTPA Enhancement of Experimental Soft Tissue Carcinoma and Hemorrhage in Magnetic Resonance Imaging

An experimental series in the rabbit was performed to test gadolinium-DTPA (Gd-DTPA) enhancement of VX-2 carcinoma and hemorrhages induced in the soft tissues. The recognition of both malignant and benign lesions was greatly facilitated on T1 weighted images after intravenous administration of 0.3 mmol Gd-DTPA/kg body weight because of reduced T1 relaxation times. Gd-DTPA enhancement reached its maximum after 10–15 minutes and was most apparent in tumor tissue, connective tissue surrounding the tumor and in the area of fresh hemorrhage.

Long-term type 1 diabetes influences haematopoietic stem cells by reducing vascular repair potential and increasing inflammatory monocyte generation in a murine model

AIMS/HYPOTHESIS

We sought to determine the impact of long-standing type 1 diabetes on haematopoietic stem/progenitor cell (HSC) number and function and to examine the impact of modulating glycoprotein (GP)130 receptor in these cells.

METHODS

Wild-type, gp130(-/-) and GFP chimeric mice were treated with streptozotocin to induce type 1 diabetes. Bone marrow (BM)-derived cells were used for colony-formation assay, quantification of side population (SP) cells, examination of gene expression, nitric oxide measurement and migration studies. Endothelial progenitor cells (EPCs), a population of vascular precursors derived from HSCs, were compared in diabetic and control mice. Cytokines were measured in BM supernatant fractions by ELISA and protein array. Flow cytometry was performed on enzymatically dissociated retina from gfp(+) chimeric mice and used to assess BM cell recruitment to the retina, kidney and blood.

RESULTS

BM cells from the 12-month-diabetic mice showed reduced colony-forming ability, depletion of SP-HSCs with a proportional increase in SP-HSCs residing in hypoxic regions of BM, decreased EPC numbers, and reduced eNos (also known as Nos3) but increased iNos (also known as Nos2) and oxidative stress-related genes. BM supernatant fraction showed increased cytokines, GP130 ligands and monocyte/macrophage stimulating factor. Retina, kidney and peripheral blood showed increased numbers of CD11b(+)/CD45(hi)/ CCR2(+)/Ly6C(hi) inflammatory monocytes. Diabetic gp130(-/-) mice were protected from development of diabetes-induced changes in their HSCs.

CONCLUSIONS/INTERPRETATION

The BM microenvironment of type 1 diabetic mice can lead to changes in haematopoiesis, with generation of more monocytes and fewer EPCs contributing to development of microvascular complications. Inhibition of GP130 activation may serve as a therapeutic strategy to improve the key aspects of this dysfunction.

Markers of airway inflammation in the exhaled breath condensate of preschool wheezers

BACKGROUND

Leukotrienes (LT), isoprostanes, and nitrites/nitrates are biomarkers of airway inflammation and oxidative stress that can be detected in exhaled breath condensate (EBC). The aim of this study was to evaluate LTB4, LTE4, 8-isoprostane, and nitrite/nitrate levels in the EBC of healthy and wheezing preschool children.

METHODS

We included 21 healthy nonatopic children and 25 patients with recurrent wheezing episodes in a cross-sectional study. LTB4, LTE4, and 8-isoprostane concentrations were measured directly in EBC using a specific enzyme immunoassay; nitrite/nitrate concentrations were measured using a colorimetric assay.

RESULTS

LTB4 concentrations were higher in children with wheezing episodes than in healthy controls (76 pg/mL vs 20 pg/mL, P < .001). LTE4 was increased in children with wheezing episodes than in healthy controls (68 pg/mL vs 35 pg/mL, P < .001). Nitrite concentrations were higher in children with wheezing episodes than in healthy controls (14 pg/mL vs 9.7 pg/mL, P < .03). We found no differences in 8-isoprostane and nitrate concentrations between the patients and the healthy controls.

CONCLUSIONS

Our findings suggest that EBC is a suitable noninvasive method for the assessment of airway inflammation and oxidative stress in preschool children. Levels of LTB4, LTE4, and nitrites were higher in children with recurrent wheezing episodes than in healthy controls.

Application of multiplex PCR approaches for shark molecular identification: feasibility and applications for fisheries management and conservation in the Eastern Tropical Pacific

Here we describe the application of new and existing multiplex PCR methodologies for shark species molecular identification. Four multiplex systems (group ID, thresher sharks, hammerhead sharks and miscellaneous shark) were employed with primers previously described and some designed in this study, which allow for species identification after running PCR products through an agarose gel. This system was implemented for samples (bodies and fins) collected from unidentified sharks landed in the port of Buenaventura and from confiscated tissues obtained from illegal fishing around the Malpelo Island Marine Protected Area, Pacific Coast of Colombia. This method has allowed reliable identification, to date, of 407 samples to the genus and/or species levels, most of them (380) identified as the pelagic thresher shark (Alopias pelagicus). Another seven samples were identified as scalloped hammerhead sharks (Sphyrna lewini). This is an easy-to-implement and reliable identification method that could even be used locally to monitor shark captures in the main fishing ports of developed and developing countries.

Captive-born intergeneric hybrid of a Guiana and bottlenose dolphin: Sotalia guianensis x Tursiops truncatus

Bottlenose dolphins (Tursiops truncatus) and Guiana dolphin (Sotalia guianensis) live in sympatry along the Caribbean Coast of Central and South America and social interactions between these species have been described in the Caribbean Coast of Costa Rica, including sexual encounters. Here we examine and document the only known hybridization event between a male Guiana dolphin and a female bottlenose dolphin, in captivity at Oceanario Islas del Rosario (Colombian Caribbean), using photographic and genetic evidence from mitochondrial DNA markers and nuclear autosomal introns.

Palladium(II) binding to N(7) of acyclovir: DNA interaction and herpes simplex virus (HSV-1) inhibitory activity

Cytotoxicity and herpes simplex virus (HSV-1) inhibitory activity of acyclovir (ACV), 9-[(2-hydroxyethoxy)methyl]guanine, and the palladium(II) coordination complex cis-[PdCl(2)(H(2)O)(N7-ACV)] x ACV x xH(2)O have been tested in African green monkey kidney (Vero line) epithelial cell cultures. The N(7) position of ACV represents the preferred binding site to afford a pseudo-chelate N7/O6 Pd(II) complex involving H-bonds with the cis H(2)O molecule. The Pd(II)-ACV complex has been structurally characterized by FTIR and (1)H NMR spectroscopy techniques, chemical composition was measured by elemental analysis, and the thermoanalytical study was performed by TG/DTA. The recognition of secondary ACV molecules by the Pd(II) derivative promotes cooperatively potent HSV-1 inhibitory activity which, in turn, strongly depends on concentration conditions. At the optimal concentration of 10 microM, this complex exhibits antiviral efficiency in vitro, approximately hundred-fold (ca. 1.87 log(10)) more effective in herpes-infected cells when compared with that of the parent ACV molecules. The molecular-level observation of noticeable modifications caused by the complex on the morphology of the plasmid pBR322 DNA was monitored by AFM, whose mutual interaction evolves to eventually afford DNA condensates upon increasing the period of incubation.

Inhibition of protein kinase CK2 suppresses angiogenesis and hematopoietic stem cell recruitment to retinal neovascularization sites

Ubiquitous protein kinase CK2 participates in a variety of key cellular functions. We have explored CK2 involvement in angiogenesis. As shown previously, CK2 inhibition reduced endothelial cell proliferation, survival and migration, tube formation, and secondary sprouting on Matrigel. Intraperitoneally administered CK2 inhibitors significantly reduced preretinal neovascularization in a mouse model of proliferative retinopathy. In this model, CK2 inhibitors had an additive effect with somatostatin analog, octreotide, resulting in marked dose reduction for the drug to achieve the same effect. CK2 inhibitors may thus emerge as potent future drugs aimed at inhibiting pathological angiogenesis. Immunostaining of the retina revealed predominant CK2 expression in astrocytes. In human diabetic retinas, mRNA levels of all CK2 subunits decreased, consistent with increased apoptosis. Importantly, a specific CK2 inhibitor prevented recruitment of bone marrow-derived hematopoietic stem cells to areas of retinal neovascularization. This may provide a novel mechanism of action of CK2 inhibitors on newly forming vessels.

Reduction in preretinal neovascularization by ribozymes that cleave the A2B adenosine receptor mRNA

Adenosine modulates a variety of cellular functions by interacting with specific cell surface G protein-coupled receptors (A1, A2A, A2B, and A3) and is a potential mediator of angiogenesis through the A2B receptor. The lack of a potent, selective A2B receptor inhibitor has hampered its characterization. Our goal was to design a hammerhead ribozyme that would specifically cleave the A2B receptor mRNA and examine its effect on retinal angiogenesis. Ribozymes specific for the mouse and human A2B receptor mRNAs were designed and cloned in expression plasmids. Human embryonic kidney (HEK) 293 cells were transfected with these plasmids and A2B receptor mRNA levels were determined by quantitative real-time RT-PCR. Human retinal endothelial cells (HRECs) were also transfected and cell migration was examined. The effects of these ribozymes on the levels of preretinal neovascularization were determined using a neonatal mouse model of oxygen-induced retinopathy (OIR). We produced a ribozyme with a Vmax of 515+/-125 pmol/min and a Kcat of 36.1+/-8.3 min(-1) (P< or =1x10(-5)). Transfection of HEK293 cells with the plasmid expressing the ribozyme reduced A2B receptor mRNA levels by 45+/-4.8% (P=5.1x10(-5)). Transfection of HRECs reduced NECA-stimulated migration of cells by 47.3+/-1.2% (P=7x10(-4)). Intraocular injection of the constructs into the mouse model reduced preretinal neovascularization by 53.5+/-8.2% (P=4.5x10(-5)). Our results suggest that the A2B receptor ribozyme will provide a tool for the selective inhibition of this receptor and provide further support for the role of A2B receptor in retinal angiogenesis.

Modulation of rat liver cytochrome P450 by protein restriction assessed by biochemical and bacterial mutagenicity methods [corrected]

Protein restriction (PR) significantly inhibits spontaneous and chemical carcinogenesis. Several factors seem to be involved in this effect, including a decrease in body weight, cellular proliferation and DNA damage and an increase in antioxidant defenses. The current study was designed to determine modifications in some hepatic cytochromes P450 (CYPs) due to a hypoproteic diet and to investigate its implications on chemical mutagenesis. Western blot analysis showed decreases of 73, 40 and 74% in CYP1A, CYP2B and CYP2E1 protein concentrations in hepatic microsomes from animals fed a protein-restricted (6% protein) diet for 6 weeks in comparison with microsomes from rats fed a 24% protein diet during the same period. In the same way, low protein fed animals showed a 3.5-fold decrease in hepatic CYP1A1-associated ethoxyresorufin O-deethylase activity, a 6-fold decrease in CYP1A2-associated methoxyresorufin O-demethylase activity, a 1.7-fold decrease in CYP2B1-associated penthoxyresorufin O-dealkylase activity, a 9-fold decrease in CYP2B2-associated benzyloxyresorufin O-dealkylase and, finally, a 3.4-fold decrease in CYP2E1-associated 4-nitrophenol hydroxylase activity. As a result of decreased CYP hepatic protein concentrations and enzymatic activities, liver S9 from rats fed a hypoproteic diet was less efficient in activating promutagens than S9 prepared from rats fed a 24% protein diet in the Ames test. Mutagenic potency obtained with protein-restricted S9 was reduced 25-fold for 2-aminoanthracene, 1.5-fold for N-nitrosodipropylamine, 12.5-fold for N-nitrosodibutylamine, 2-fold for cyclophosphamide and N-nitrosopyrrolidine and 71-fold for N-nitrosodimethylamine. However, the mutagenic potency of benzo[a]pyrene was the same (4 revertants/ microg) with S9 derived from rats fed either a 6 or 24% protein diet.

Adenosine receptor antagonists and retinal neovascularization in vivo

PURPOSE

The role of adenosine receptor (AdoR) antagonists in human retinal endothelial cell function in vitro has previously been determined. In this study, efficacy of AdoR antagonist administration in reducing retinal neovascularization was examined in a mouse pup model of oxygen-induced retinopathy.

METHODS

A previously described model of oxygen-induced retinal neovascularization in newborn mouse pups was used to examine the effect of various AdoR antagonists on neovascularization. The nonselective AdoR antagonist xanthine amine congener (XAC), the A(2A)-selective antagonist ZM241385, the A(2B)-selective antagonists 3-N-propylxanthine (enprofylline) and 3-isobutyl-8-pyrrolidinoxanthine (IPDX), and the A(1)-selective antagonist cyclopentyl-1,3-dipropylxanthine (CPX) were used. After the hyperoxia exposure the animals received daily intraperitoneal injections of pharmacologically relevant doses of AdoR antagonists for 5 days. Control animals received vehicle (0.1% dimethyl sulfoxide [DMSO]) alone. The animals were then killed and perfused with fluorescein-dextran. Wholemounts of retinas from one eye were prepared and examined, whereas the retinas of the contralateral eye were embedded, sectioned, and stained for counting neovascular nuclei extending beyond the internal limiting membrane into the vitreous.

RESULTS

Angiography of wholemount retinas showed reduction of neovascular tufts in animals treated with selective A(2B) AdoR antagonists. Quantification of the extraretinal neovascular nuclei showed that only animals treated with XAC, enprofylline, or IPDX showed a significant reduction in retinal neovascularization. By contrast, neither CPX nor ZM241385 had an effect on neovascularization.

CONCLUSIONS

The A(2B)-selective AdoR antagonists inhibited oxygen-induced retinal neovascularization in vivo and may provide a basis for developing pharmacologic therapies for the treatment of proliferative retinopathies.

Potential role of fomites in the vehicular transmission of human astroviruses

The persistence of human astroviruses dried on representative porous (paper) and nonporous (china) surfaces was investigated. Long-term astrovirus survival on fomites was monitored by an integrated cell culture-reverse transcription-PCR procedure. Viruses were applied to inanimate surfaces in the presence and absence of fecal material, and their survival was assayed at 4 and 20 degrees C with high relative humidity. Astroviruses exhibited a notable persistence when dried on porous and nonporous materials, particularly at low temperature. Short-term survival of astroviruses on fomites was compared to that of other enteric viruses significant for health, such as rotavirus, adenovirus, poliovirus, and hepatitis A virus. Overall, astroviruses persisted better than poliovirus and adenovirus, although they exhibited a shorter survival than rotavirus and hepatitis A virus. Astroviruses show a high level of persistence at the desiccation step, which is of major significance in determining the chance of subsequent virus survival dried on fomites. Astroviruses are able to survive on inert surfaces long enough to suggest that fomites may play a relevant role in the secondary transmission of astrovirus diarrhea.

Proliferation, migration, and ERK activation in human retinal endothelial cells through A(2B) adenosine receptor stimulation

PURPOSE

The nucleoside adenosine has been implicated in angiogenesis. A previous study demonstrated that activation of the A(2B) adenosine receptor (AdoR) increases cAMP accumulation, cell proliferation, and VEGF expression in human retinal endothelial cells (HRECs). In the present study, the role of this receptor was further characterized by examination of the effects of the selective A(2B) AdoR antagonists 3-N-propylxanthine (enprofylline) and 3-isobutyl-8-pyrrolidinoxanthine (IPDX) on AdoR-mediated HREC proliferation, capillary tube formation, and signal-transduction pathways.

METHODS

HRECs were exposed to the adenosine analogue 5'-N-ethylcarboxamido-adenosine (NECA) in the absence or presence of AdoR antagonists. Migration was measured using Boyden chambers. Proliferation was assessed by counting cells. Western analysis was used to assess extracellular signal-related kinase (ERK) and cAMP response element-binding protein (CREB) in cell lysates. The effect of AdoR activation on tube formation was studied using cells grown on a synthetic basement membrane matrix.

RESULTS

NECA induced proliferation in a concentration-dependent manner that was inhibited by enprofylline and IPDX. NECA stimulated chemotaxis in a concentration-dependent manner that was also blocked by both A(2B) AdoR antagonists. NECA activated ERK and CREB in HRECs. Both A(2B) AdoR antagonists diminished activation of ERK by NECA exposure. ERK activation was also blocked by the ERK-mitogen-activated protein kinase (MAPK) inhibitor PD98059, but not by the protein kinase A (PKA) inhibitor H-89. CREB activation was blocked by H-89, but not by PD98059, suggesting that ERK activation is independent of PKA. NECA enhanced tube formation on the matrix, whereas both A(2B) AdoR antagonists attenuated this effect.

CONCLUSIONS

The selective A(2B) AdoR antagonists, enprofylline and IPDX, inhibited NECA-stimulated proliferation, ERK activation, cell migration, and capillary tube formation. A(2B) AdoR inhibition may offer a way to inhibit retinal angiogenesis and provide a novel therapeutic approach to treatment of diseases associated with aberrant neovascularization, such as diabetic retinopathy and retinopathy of prematurity.

Modulation of retinal endothelial cell behaviour by insulin-like growth factor I and somatostatin analogues: implications for diabetic retinopathy

Evidence suggests the involvement of growth hormone (GH), insulin-like growth factor I (IGF-I) and somatostatin in the pathology associated with diabetic retinopathy. We examined the effect of IGF-I on human retinal endothelial cell (HREC) survival following high glucose exposure and serum starvation, examined the signalling pathways mediating the protective effect of IGF-I on HREC, and characterized somatostatin receptor-induced retinal endothelial cell death. IGF-I (10 ng/ml) protected HREC from apoptosis induced by high glucose and serum starvation. Wortmannin, a specific inhibitor of phosphotidylinositol-3-kinase, blocks the ability of IGF-I to protect HREC from apoptosis. Incubation of HREC in serum-free medium caused a time-dependent increase in c-Jun N-terminal kinase (JNK) activity, and continuous culture of HREC in the presence of IGF-I or vascular endothelial growth factor (VEGF) prevented JNK activation and arrested apoptosis. Activation of tyrosine kinase receptors results in extracellular signal-related kinase (ERK) activation and activation of ERK is required for proliferation. Both IGF-I and VEGF produced a time- and concentration-dependent increase in the activation of ERK. Type 2 and type 3 somatostatin receptors have been implicated in cell-cycle arrest and apoptosis. Activation of the type 3 receptor in HREC resulted in cell death. These studies suggest that IGF-I is critical for HREC survival, and that somatostatin analogues acting through the type 3 receptor have direct effects on retinal endothelial cells. Furthermore, it appears that the therapeutic efficacy of somatostatin analogues lies not only in systemic inhibition of GH, but also in modulating local growth factor effects.

Evolution of river dolphins

The world's river dolphins (Inia, Pontoporia, Lipotes and Platanista) are among the least known and most endangered of all cetaceans. The four extant genera inhabit geographically disjunct river systems and exhibit highly modified morphologies, leading many cetologists to regard river dolphins as an unnatural group. Numerous arrangements have been proposed for their phylogenetic relationships to one another and to other odontocete cetaceans. These alternative views strongly affect the biogeographical and evolutionary implications raised by the important, although limited, fossil record of river dolphins. We present a hypothesis of river dolphin relationships based on phylogenetic analysis of three mitochondrial genes for 29 cetacean species, concluding that the four genera represent three separate, ancient branches in odontocete evolution. Our molecular phylogeny corresponds well with the first fossil appearances of the primary lineages of modern odontocetes. Integrating relevant events in Tertiary palaeoceanography, we develop a scenario for river dolphin evolution during the globally high sea levels of the Middle Miocene. We suggest that ancestors of the four extant river dolphin lineages colonized the shallow epicontintental seas that inundated the Amazon, Paraná, Yangtze and Indo-Gangetic river basins, subsequently remaining in these extensive waterways during their transition to freshwater with the Late Neogene trend of sea-level lowering.

Astrovirus detection in wastewater samples

Procedures for the detection of astroviruses in wastewater samples have been developed and evaluated. Following these methodologies, we investigated the occurrence of astroviruses in wastewater samples from three different sewage treatments plants located in Southern France and two in the Barcelona area. Some positive samples were genotyped by analysis of a fragment of the ORF1a by restriction fragment length polymorphism (RFLP) with endonuclease DdeI. The amplimers generated contain several sites for the DdeI restriction endonuclease, being the number and location of sites different between strains.

Plasminogen activator inhibitor (PAI)-1 overexpression in retinal microvessels of PAI-1 transgenic mice

PURPOSE

Previous studies have suggested that disturbances in plasminogen activator inhibitor (PAI)-1 may be relevant to the development of diabetic microvascular complications. To determine whether overexpression of PAI-1 in cells of retinal microvasculature would result in a disease similar to that observed in diabetes, ocular tissue from transgenic mice that overexpress human PAI-1 were examined.

METHODS

Transgenic mice were administered ZnSO4 (25 mM) in their water for up to 49 weeks to activate the metallothionein promoter and stimulate human PAI-1. Colloidal gold immunocytochemistry was used to quantify the human PAI-1 antigen at 7, 20, 34, and 49 weeks of ZnSO4 administration. Cross sections of retinal microvessels were examined by electron microscopy for changes in basement membrane (BM) thickness. Retinal digest preparations were examined by light microscopy for possible microangiopathy, including changes in endothelial cell-to-pericyte ratios.

RESULTS

Human PAI-1 immunoreactivity was detected throughout the retinal capillaries of transgenic mice receiving zinc and increased significantly (P < 0.001) after 20 to 49 weeks of ZnSO4 administration compared with age-matched transgenic control mice. At 20 and 49 weeks, retinal capillaries of transgenic mice that received zinc showed significantly thickened BMs compared with control animals (P < 0.001). Moreover, wholemounts of the retinal vasculature from PAI-1 transgenic mice demonstrated an increased endothelial cell-to-pericyte ratio.

CONCLUSIONS

PAI-1 overexpression in retinal microvasculature leads to retinal disease similar to that observed in diabetic retinopathy.

The efficacy of octreotide in the therapy of severe nonproliferative and early proliferative diabetic retinopathy: a randomized controlled study

OBJECTIVE

The pilot study examined the ability of octreotide to retard progression of diabetic retinopathy (DR) and delay the need for panretinal photocoagulation (PRP) in patients with advanced stages of retinal disease.

RESEARCH DESIGN AND METHODS

Patients with severe nonproliferative DR (NPDR) or early non-high-risk proliferative DR (PDR) were randomly assigned to conventional diabetes management (control group, 12 patients) or to treatment with maximally tolerated doses of octreotide (200-5,000 microg/day subcutaneously; 11 patients). Ocular changes in each eye were assessed at a minimum of every 3 months for 15 months or until disease progressed to high-risk PDR requiring laser surgery. Endocrine assessments occurred at 3-month intervals during the study

RESULTS

Only 1 of 22 eyes from patients treated with octreotide reached high-risk PDR requiring PRP, compared with control patients, in whom 9 of 24 eyes required PRP. The decreased incidence of progression requiring laser surgery was statistically significant if events were considered independently (P < 0.006). The incidence of ocular disease progression was only 27% in patients treated with octreotide compared with 42% in patients with conventional diabetes management. This treatment effect on whether the retina worsened approached statistical significance using repeated measures analysis (P = 0.0605). Endocrine management was similar between treatment groups. Thyroxine replacement therapy was administered to maintain a euthyroid state for all octreotide-treated patients and 7 of 12 control patients.

CONCLUSIONS

Our results suggest that octreotide treatment in euthyroid patients may retard progression of advanced DR and may delay the time to laser surgery.

Adenosine receptor activation induces vascular endothelial growth factor in human retinal endothelial cells

Adenosine, released in increased amounts by hypoxic tissues, is thought to be an angiogenic factor that links altered cellular metabolism caused by oxygen deprivation to compensatory angiogenesis. Adenosine interacts with 4 subtypes of G protein-coupled receptors, termed A(1), A(2A), A(2B), and A(3). We investigated whether adenosine causes proliferation of human retinal endothelial cells (HRECs) and synthesis of vascular endothelial growth factor (VEGF) and, if so, which adenosine receptor subtype mediates these effects. The nonselective adenosine receptor agonist 5'-N-ethylcarboxamidoadenosine (NECA), in a concentration-dependent manner, increased both VEGF mRNA and protein expression by HRECs, as well as proliferation. This proliferative effect of NECA was inhibited by the addition of anti-human VEGF antibody. NECA also increased insulin-like growth factor-I and basic fibroblast growth factor mRNA expression in a time-dependent manner and cAMP accumulation in these cells. In contrast, neither the A(1) agonist N(6)-cyclopentyladenosine nor the A(2A) agonist 2-p-(2-carboxyethyl) phenethylamino-NECA caused any of the above effects of NECA. The effects of NECA were not significantly attenuated by either the A(2A) antagonist SCH58261 or the A(1) antagonist 8-cyclopentyl-1, 3-dipropylxanthine. However, the nonselective adenosine receptor antagonist xanthine amine congener completely inhibited the effects of NECA. Addition of antisense oligonucleotide complementary to A(2B) adenosine receptor mRNA inhibited VEGF protein production by HRECs after NECA stimulation. Thus, the A(2B) adenosine receptor subtype appears to mediate the actions of adenosine to increase growth factor production, cAMP content, and cell proliferation of HRECs. Adenosine activates the A(2B) adenosine receptor in HRECs, which may lead to neovascularization by a mechanism involving increased angiogenic growth factor expression.

[Extracorporeal respiratory assistance (ECRA): initial experiences in Spain]

The attendance respiratory extracorporeal (AREC) is an oxygenation form for membrane extracorporeal with flow tidal and veno-venous cannula described by Chevalier et al. in 1990. We present our clinical experience so much with AREC in system veno-venous flow tidal as veno-arterial. From october of 1997 until the present time we have treated three patients by means AREC, in two patients with veno-venous system and in one veno-arterial. In all the cases bomb Collin-Cardio has been used with bladder for flow tidal and membrane of oxygenation of 0.8 m2, being inserted a system of alternative clamp of the branches of the circuit. The system AREC has been used in two patients with congenial diaphragmatic hernia, right in a case and left in the other one. The gestational age was of 38 and 36 weeks with a weight of 3,200 and 2,900 grams. Both patients were remitted from other centers by failure of the conventional treatment. In both cases the indication of AREC was the sharp deterioration of the general state with failure of the conservative treatment, being the previous oxygenation index of 109 and 112. The third patient precised veno-arterial AREC for ventricular failure during the correction of the congenital heart disease, this patient was 5 month old and the weight was 5,000 grams. The duration of AREC in the cases of congenital diaphragmatic hernia was of 14 and 10 days. In a patient the diaphragmatic hernia was corrected at the 55 hours of being in AREC. In the second case the hernia had been surgical corrected in another center. The exit of AREC in both cases carries out after a discreet improvement of the lung function. Both patients died at the 24 and 48 hours of the decannulation for cerebral hemorrhage and respiratory failure. The third patient stayed stable in veno-arterial AREC during 4 days, with hemodynamic support of 130 ml/kg/min, retiring the support to present absence of cerebral activity.

CONCLUSIONS

With the derived limitations of the extreme severity of the treated cases and the current phase of beginning of the AREC team, we think that it is a useful and available technique in our country, for the handling of patient with cardiorespiratory failure while waiting for improvement of their base pathology.

Expression of IGF-1, IGF-1 receptor and TGF-beta following balloon angioplasty in atherosclerotic and normal rabbit iliac arteries: an immunocytochemical study

Growth factors have been implicated in the pathogenesis of restenosis (myointimal hyperplasia after coronary interventions). In this study, we examined the expression of insulin-like growth factor-I (IGF-1), IGF-1 receptor, and transforming growth factor-beta (TGF-beta) in atherosclerotic and normal rabbit iliac arteries following overstretch balloon angioplasty of the iliac arteries to create a vascular lesion. Animals were sacrificed at 0, 3, 7, 15 and 42 days post angioplasty. The iliac arteries were processed for immunocytochemical localization of IGF-1, IGF-1 receptor and TGF-beta using colloidal gold and the data were quantitatively analyzed. IGF-1, IGF-1 receptor and TGF-beta immunoreactivity were all significantly increased in atherosclerotic arteries compared to control at all of the time points examined. Following balloon angioplasty, the levels of IGF-1 and IGF-1 receptor increased significantly in both control and even further in hypercholesterolemic vessels. In control vessels, the IGF-1 levels returned to preintervention levels, while in atherosclerotic vessels, the levels of IGF-1 and IGF-1 receptor remained elevated. In addition, TGF-beta levels in control vessels showed an initial rise in the first week following injury but then returned to baseline levels. In contrast, atherosclerotic vessels demonstrated a sustained expression of TGF-beta. Thus, IGF-1 and TGF-beta expression is different in normal vs. atherosclerotic vessels following vascular injury. The intensity of expression of IGF-1 and its receptor, which is not reduced at 42 days compared to 15 days following injury, support a role for IGF-1 in smooth muscle cell proliferation and migration. The sustained increase in TGF-beta could facilitate extracellular matrix (ECM) accumulation. Local vascular therapy that is directed towards modulating the effects of IGF-1 and TGF-beta could reduce restenosis.

Matrix metalloproteinase expression in human retinal microvascular cells

The degree of hyperglycemia correlates with the development of diabetic retinopathy. We investigated the effect of glucose on the expression of matrix metalloproteinase (MMP)-2 and MMP-9 (72-kDa and 92-kDa type IV collagenases, respectively) by human retinal microvascular endothelial cells (HRECs). Cultured HRECs from nondiabetic and diabetic donors were exposed to 5 or 30 mmol/l glucose. Using gelatin zymography, conditioned medium (CM) from all cultures revealed a gelatinolytic band migrating at 65 kDa (representing the proform of MMP-2 that runs at 72 kDa under reducing conditions). This band was unchanged by glucose exposure or the disease state of the donors. CM from nondiabetic HREC cultures demonstrated an additional proteolytic activity migrating at 90 kDa when cells were exposed to 30 mmol/l glucose, but not when they were exposed to 5 mmol/l glucose. This same activity was seen in CM from HREC cultures of diabetic origin in the presence of both 5 and 30 mmol/l glucose. Western analysis confirmed the identity of the 65-kDa band as MMP-2. The anomalous activity at 90 kDa was identified as MMP-2 associated and co-migrating with a fibronectin fragment. Competition-based reverse transcription-polymerase chain reaction revealed that nondiabetic and diabetic HRECs expressed constitutively mRNA for MMP-2, MMP-9, tissue inhibitor of metalloproteinase (TIMP)-1, TIMP-2, and fibronectin. After exposure to 5 or 30 mmol/l glucose, no changes were detected in mRNA levels in MMP-2 or MMP-9, their inhibitors TIMP-1 and TIMP-2, or fibronectin in either nondiabetic or diabetic HREC cultures. These results support the notion that modulation of MMP function by extracellular matrix components occurs in response to glucose and may be relevant to the development of diabetic retinopathy.

Fibronectin fragments modulate human retinal capillary cell proliferation and migration

Capillary morphogenesis involves cell-cell and cell-matrix interactions. Proteases elaborated by capillary cells modify the extracellular matrix (ECM) to facilitate capillary tube formation. Previously, we detected the presence of fibronectin fragments (Fn-f) associated with the proform of matrix metalloprotease-2 (MMP-2) in conditioned medium of human retinal endothelial cells (HRECs). Association of this fragment to latent MMP-2 prevented autocatalytic activation of MMP-2, suggesting a modulatory role of Fn-f in MMP-2 activation. In this report, we examined the potential role of Fn-f on two processes involved in angiogenesis, proliferation and migration of vascular cells. The effects of Fn-f on proliferation were determined by DNA synthesis and cell counts. Their effects on migration were assessed using modified Boyden chambers. Seven Fn-f were tested on vascular cell migration and/or proliferation. Three Fn-f induced migration. Fn-f of 30-kDa and 120-kDa size positively affected proliferation of microvascular cells but not macrovascular cells. A 45-kDa gelatin binding fragment of Fn inhibited HREC proliferation but stimulated pericyte and smooth muscle cell proliferation. The potency of these fragments exceeded that of the known angiogenic growth factor, basic fibroblast growth factor (bFGF), on HREC migration. ECM components such as fibronectin may influence capillary morphogenesis by the generation of fragments that can modulate proliferation, migration, and protease activation. In the setting of diabetes, excess Fn is generated and is available for degradation. Thus, the production of Fn-f may be specifically relevant to the angiogenesis observed in proliferative diabetic retinopathy.

[Secondary effects of prostaglandin E1 on the management of hypoplastic left heart syndrome while waiting for heart transplantation]

OBJECTIVE

Newborns with hypoplastic left heart syndrome (HLHS) included in the heart transplant program depend on continuous prostaglandin E1 (PGE1) perfusion for a prolonged period of time, which can result in various side effects. The objective of this study was to analyze the side effects derived from the use of PGE1 in newborns with HLHS who are awaiting heart transplantation.

PATIENTS AND METHODS

Fifteen newborns with HLHS included in a cardiac transplant program between January 1993 and August 1996 were studied. All received continuous endovenous perfusion of PGE1 from the time of diagnosis of the cardiopathy.

RESULTS

Thirteen patients were transplanted, with 6 dying in the operating room. Seven survived. Two patients died while waiting for a transplant. All presented short term side effects derived from the continuous perfusion of PGE1, including a slight fever and irritability. However, none of them presented apnea pauses. Cortical hyperostosis and anthral hyperplasia were observed in 13 (83.3%) and 12 (80%) cases, respectively, but in all transplanted cases regression of the anthral hyperplasia was seen after 6 months and regression of the cortical hyperostosis was seen after 12 months.

CONCLUSIONS

PGE1 was effective in maintaining the permeability of the ductus arteriosus. The side effects derived from the treatment were well tolerated. The appearance of cortical hyperostosis and anthral hyperplasia is related to the duration of the perfusion and these disappear in the weeks following the suspension of PGE1 treatment.

Minerals content of Paraguayan yerba mate (Ilex paraguariensis, S.H.)

Minerals content (Fe, Ca, Mn, Mg, Na, K, Zn and Cu) of the leaves of Paraguayan yerba mate (Ilex paraguariensis, S.H.) as well as of commercial products has been determined by atomic absorption spectrophotometry. Considerable amounts of iron and calcium and remarkably high content of magnesium and potassium have been found both in the leaves and in the commercial products. Highly significant difference between the Fe content of the leaves and that of the commercial products has been found. Also, highly significant difference has been found between the Fe and Ca content of the higher quality-greater sale reputed commercial products and that of the lower quality-smaller sale reputed ones. Seasonal and soil linked variations are also presented. The nutritional and quality control significance of these findings for the MERCOSUR (Southern South America Economical Community) are discussed.

Expression of IGF-I, IGF-I receptor and IGF binding proteins-1, -2, -3, -4 and -5 in human atherectomy specimens

The molecular and cellular processes that induce rapid atherosclerotic plaque progression in patients with unstable angina and initiate restenosis following coronary interventional procedures are uncertain. We examined primary (de novo) and restenotic lesions retrieved at the time of directional coronary atherectomy for expression of insulin-like-growth factor-I (IGF-I). IGF-I receptor, and five IGF binding proteins (IGFBPs), IGFBP-1, IGFBP-2, IGFBP-3, IGFBP-4, and IGFBP-5 in smooth muscle cells (SMCs) using colloidal gold immunocytochemistry. IGF-1, its receptor and binding proteins were not detected in SMCs of normal coronary arteries. IGF-I localized primarily in synthetic smooth muscle cells (sSMCs) in both de novo and restenotic plaques. IGF-I receptor localized on sSMCs and their processes and colocalized with IGF-I. Although morphometric analysis of IGF-I and IGF-I receptor immunoreactivity in sSMCs of de novo and restenotic lesions showed comparable levels of IGF-I (3.2 +/- 1.0 and 2.9 +/- 0.9, respectively). IGF-I receptor was significantly higher in de novo lesions as compared to restenotic lesions (10.7 +/- 2.5 and 4.2 +/- 1.3, P < 0.05, respectively). IGFBP-1, IGFBP-2, IGFBP-3, IGFBP-4 and IGFBP-5 localized in the cytoplasm of sSMCs and in the extracellular matrix. Quantitative reverse transcription polymerase chain reaction (QRT-PCR) performed on de novo atherectomy specimens identified mRNA for IGF-I, IGF-I receptor, IGFBP-1, IGFBP-2, IGFBP-4, IGFBP-5 levels and detected mRNA for IGFBP-3. The expression of IGF-I, IGF-I receptor, and IGFBPs in atherectomy plaques suggests that the development of coronary obstructive lesions may be a result of changes in the IGF system.

Plasminogen activator inhibitor-1 overexpression in nonproliferative diabetic retinopathy

Plasminogen activator inhibitor-1 is secreted bidirectionally by endothelial cells, acts as the primary regulator of fibrinolysis and as a key modulator of extracellular matrix proteolysis. Elevated serum levels of plasminogen activator inhibitor-1 are observed in serum of diabetic individuals. We investigated whether plasminogen activator inhibitor-1 is overexpressed in capillaries of diabetic donors with non-proliferative retinopathy compared to non-diabetic donors. We also assessed plasminogen activator inhibitor-1 expression in an animal model of retinopathy induced by exposing rabbit retinas to insulin-like growth factor-I. Colloidal gold immunocytochemistry was used to quantify plasminogen activator-1 antigen in donor retinas from diabetic subjects (n = 10) and control subjects (n = 10). This technique was also used to examine expression of plasminogen activator inhibitor-1 for correlation with retinal changes in the insulin-like growth factor-I-induced retinopathy model (n = 14). Plasminogen activator inhibitor-1 immunoreactivity was significantly increased in the retinas of all diabetic subjects as compared to controls. In the rabbit model, the expression of plasminogen activator inhibitor-1 immunoreactivity correlated with pathological retinal changes. In both the diabetic human and insulin-like growth factor-I-injected rabbit, overproduction of plasminogen activator inhibitor-1 was seen within the lumen of capillaries, within the cytoplasm of endothelial cells and in the basement membrane and extracellular matrix surrounding these capillaries. Minimal plasminogen activator inhibitor-1 was detected in the retinas of non-diabetics and in control rabbits injected with either heat-inactivated insulin-like growth factor-I or balanced salt solution. These studies support the conclusion that plasminogen activator inhibitor-1 is overexpressed in the retinal capillaries of diabetics with non-proliferative diabetic retinopathy and in rabbits with insulin-like growth factor-I-induced retinopathy.

Induction of microsomal enzymes in liver of rats treated with cyclohexanol

The S9 fraction obtained from rats orally pretreated for 3 days with cyclohexanol was able to activate the pro-mutagen N-nitrosodimethylamine (NDMA) into highly mutagenic metabolite(s) detected in the TA100 strain of Salmonella typhimurium. NDMA was not mutagenic when uninduced S9 was used as metabolic source but was approximately twice more mutagenic with cyclohexanol-induced S9 compared to ethanol-induced S9. Separation of microsomal proteins by sodium dodecylsulfate gel electrophoresis, displayed protein bands situated in the range of 50,000 to 52,000 molecular weight induced by both, ethanol and cyclohexanol. These results are evidence of the induction properties of cyclohexanol.

Competitive RNA templates for detection and quantitation of growth factors, cytokines, extracellular matrix components and matrix metalloproteinases by RT-PCR

Detection of low-abundance mRNAs by reverse transcription-polymerase chain reaction (RT-PCR) has become a standard technique to determine gene expression by tissues and cells in culture. The ability to determine relative or absolute copy number of specific mRNAs has been difficult due to inadequate internal standards to control for sample-to-sample variation. The use of a synthetic RNA standard with identical sequences to the PCR primers allows reproducible quantitation between samples and assays. By designing multi-sequence templates, several specific mRNAs can be quantitated using a single template. Addition of multiple templates to a single RT reaction allows the quantitation of a large number of targets from as little as 4 micrograms of total RNA. In this report, we present a series of seven primer/template systems to detect and quantitate 52 specific messages, including 26 growth factors and receptors, 8 extracellular matrix components, 10 matrix-modifying enzymes and their inhibitors and 8 cytokines.

Localization of insulin-like growth factor I and inhibition of coronary smooth muscle cell growth by somatostatin analogues in human coronary smooth muscle cells. A potential treatment for restenosis?

In this study, we demonstrate, for the first time, the localization of insulin-like growth factor I (IGF-I) in de novo and restenotic human coronary atherectomy plaques by using immunocytochemical techniques. Smooth muscle cells (SMCs) exhibiting the synthetic phenotype contained a statistically significant higher concentration of IGF-I than SMCs of the contractile phenotype or SMCs from normal coronary arteries. In addition, we provide data to suggest that the long-acting somatostatin analogues octreotide and angiopeptin inhibit IGF-I- and basic fibroblast growth factor (b-FGF)- induced human coronary artery SMC proliferation. Platelet-derived growth factor (PDGF)-stimulated cultures were minimally affected by the addition of octreotide but were significantly inhibited by angiopeptin. All three growth factors stimulated SMC migration in a dose-dependent manner. The somatostatin analogues tested had no effect on growth factor-stimulated SMC migration. Our data suggest that by reducing SMC proliferation, somatostatin analogues may have clinical usefulness in reducing the high incidence of restenosis observed after percutaneous transluminal coronary artery interventions.

Gadolinium-DTPA enhancement of VX-2 carcinoma of the rabbit kidney on T1 weighted magnetic resonance images

Experimental renal carcinoma was induced by percutaneous injection of VX-2 carcinoma cells into the left kidney in New Zealand white rabbits. Magnetic resonance imaging (MRI) was performed at 0.15 T before and after intravenous injection of 0.3 mmol gadolinium-DTPA (Gd-DTPA) per kg body weight. Gd-DTPA enhanced the tumors by increasing the signal intensity on T1 weighted images. The enhancement was evident immediately after Gd-DTPA injection, increasing during the observation time of 30 minutes. Histologically the areas of enhancement corresponded well to the viable tumor tissue.

Gadolinium-DTPA enhancement of experimental soft tissue carcinoma and hemorrhage in magnetic resonance imaging

An experimental series in the rabbit was performed to test gadolinium-DTPA (Gd-DTPA) enhancement of VX-2 carcinoma and hemorrhages induced in the soft tissues. The recognition of both malignant and benign lesions was greatly facilitated on T1 weighted images after intravenous administration of 0.3 mmol Gd-DTPA/kg body weight because of reduced T1 relaxation times. Gd-DTPA enhancement reached its maximum after 10-15 minutes and was most apparent in tumor tissue, connective tissue surrounding the tumor and in the area of fresh hemorrhage.

Heterogeneity among macrophages cultured from mouse bone marrow. Morphologic, cytochemical and flow cytometric analyses

The development of macrophages in culture from mouse bone marrow was followed for 14 days by light and electron microscopy, ultrastructural cytochemistry, and flow cytometric analysis. By 10 days greater than 97% of the cells in culture were mononuclear phagocytes, and by 12 days greater than 99% were identifiable as macrophages. Ultrastructurally, three subpopulations of mononuclear phagocytes were distinguished based on the appearance of cytoplasmic structures. Early in culture, cells containing large, membrane-bounded vesicles predominated. With increasing time in culture these cells were replaced to varying degrees first by cells that contained vesicles filled with relatively dense, osmiophilic material and, finally, by macrophages that contained granules of various sizes, shapes and staining densities. Cytochemical (peroxidase and acid phosphatase) and colloidal gold uptake studies at the ultrastructural level suggested that many, if not all, of these cytoplasmic structures arose by pinocytosis and subsequent fusion of pinocytic vesicles with lysosomes. Analysis of DNA content of propidium iodide-stained nuclei by flow cytometry, coupled with the examination of cells treated with colchicine to arrest mitosis in metaphase, suggested that cell cycling was a negligible contributor to heterogeneity within cultured populations. Thus, by waiting until 12-14 days after bone marrow cultures were initiated, with partial replenishment of the culture medium at 7 days, heterogeneity could be greatly reduced in cultured macrophage populations. Taking this fact into consideration could help to reduce the variability seen in functional studies of macrophage populations that are less homogeneous.