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D Wink

Publications and source records attributed to D Wink.

12 recordsLinked to original sources
PubMed2000

S-nitrosoglutathione reduces nonocclusive thrombosis rate following balloon overstretch injury and intracoronary irradiation of porcine coronary arteries.

PURPOSE: Intracoronary radiation (IR) suppresses neointima formation following balloon injury in animal models. High doses of radiation exacerbate thrombosis and delay re-endothelialization. The free radical nitric oxide (NO) has been reported to inhibit platelet aggregation, reduce neointimal hyperplasia, and stimulate re-endothelialization. This study examined the effects of a chemical NO donor on neointima formation, thrombosis, and healing of irradiated porcine coronary arteries. METHODS AND MATERIALS: Vascular lesions were created in the coronary arteries of 59 domestic swine by overstretch balloon injury. Arteries were then left untreated or were treated with intracoronary gamma-radiation using Iridium-192 in each artery to deliver 5 or 15 Gy at 2 mm from the center of the source. The chemical NO donor S-nitrosoglutathione (GSNO) was infused i.v. at a rate of 250 microg/min for 10 min before injury, followed by a continuous infusion for 60 min. Animals were euthanized at 14 days and their arteries were analyzed for histomorphometric indices of proliferation and thrombosis. RESULTS: A dose of 15 Gy reduced the ratio of intimal area to medial fracture length (IA/FL) versus control (0.06 +/- 0.05 0.54 +/- 0.10 [p < 0. 001]) but increased the nonocclusive thrombosis rate compared to controls (85% vs. 30%; p < 0.05). A low dose of 5 Gy did not affect neointima formation. Treatment with GSNO reduced thrombosis in all treated groups: control, 15%; 5 Gy, 18%; and 15 Gy, 35% (p < 0.05) without affecting neointima formation. CONCLUSION: Systemic administration of GSNO during balloon injury and IR was tolerated well by the swine and resulted in reduction of the thrombosis rate, especially at high doses, without apparent effect on neointima formation.

Animals↗
PubMed2000

Neuroprotective antioxidants from marijuana.

Cannabidiol and other cannabinoids were examined as neuroprotectants in rat cortical neuron cultures exposed to toxic levels of the neurotransmitter, glutamate. The psychotropic cannabinoid receptor agonist delta 9-tetrahydrocannabinol (THC) and cannabidiol, (a non-psychoactive constituent of marijuana), both reduced NMDA, AMPA and kainate receptor mediated neurotoxicities. Neuroprotection was not affected by cannabinoid receptor antagonist, indicating a (cannabinoid) receptor-independent mechanism of action. Glutamate toxicity can be reduced by antioxidants. Using cyclic voltametry and a fenton reaction based system, it was demonstrated that Cannabidiol, THC and other cannabinoids are potent antioxidants. As evidence that cannabinoids can act as an antioxidants in neuronal cultures, cannabidiol was demonstrated to reduce hydroperoxide toxicity in neurons. In a head to head trial of the abilities of various antioxidants to prevent glutamate toxicity, cannabidiol was superior to both alpha-tocopherol and ascorbate in protective capacity. Recent preliminary studies in a rat model of focal cerebral ischemia suggest that cannabidiol may be at least as effective in vivo as seen in these in vitro studies.

Animals↗
PubMed1999

Induction of nitric oxide production in infiltrating leukocytes following in vivo irradiation of tumor-bearing mice.

Nitric oxide (NO) has been implicated both in regression and progression of tumors due to its production by both tumor cells and infiltrating leukocytes. Ionizing radiation causes the regression of tumors, and can augment the production of NO by macrophages in vitro. We examined the cellular and systemic production of NO in mice in which radiation-resistant RIF-1 fibrosarcoma cells were implanted subcutaneously and were then either irradiated or sham-treated at the tumor site. Ten days following implantation of the tumors, CD45- tumor cells and CD45+ leukocytes were derived from resected tumors immediately after irradiation with 60 Gy, a dose previously reported to reduce tumor growth. Leukocytes from tumors of irradiated hosts produced spontaneously up to four-fold more NO than did either leukocytes from unirradiated mice or CD45- tumor cells from either unirradiated or irradiated mice. Between days 10-14 following tumor implantation, serum NO2-/NO3- increased in both irradiated and unirradiated mice to an equal extent, culminating in levels higher than those of non-tumor-bearing mice. Though NO production is elevated in macrophages treated with 1-10 Gy of radiation in vitro, higher doses may be required by tumor-infiltrating macrophages in vivo and thus may indicate that tumor-infiltrating macrophages are deactivated.

Animals↗
PubMed1998

Cannabidiol and (-)Delta9-tetrahydrocannabinol are neuroprotective antioxidants.

The neuroprotective actions of cannabidiol and other cannabinoids were examined in rat cortical neuron cultures exposed to toxic levels of the excitatory neurotransmitter glutamate. Glutamate toxicity was reduced by both cannabidiol, a nonpsychoactive constituent of marijuana, and the psychotropic cannabinoid (-)Delta9-tetrahydrocannabinol (THC). Cannabinoids protected equally well against neurotoxicity mediated by N-methyl-D-aspartate receptors, 2-amino-3-(4-butyl-3-hydroxyisoxazol-5-yl)propionic acid receptors, or kainate receptors. N-methyl-D-aspartate receptor-induced toxicity has been shown to be calcium dependent; this study demonstrates that 2-amino-3-(4-butyl-3-hydroxyisoxazol-5-yl)propionic acid/kainate receptor-type neurotoxicity is also calcium-dependent, partly mediated by voltage sensitive calcium channels. The neuroprotection observed with cannabidiol and THC was unaffected by cannabinoid receptor antagonist, indicating it to be cannabinoid receptor independent. Previous studies have shown that glutamate toxicity may be prevented by antioxidants. Cannabidiol, THC and several synthetic cannabinoids all were demonstrated to be antioxidants by cyclic voltametry. Cannabidiol and THC also were shown to prevent hydroperoxide-induced oxidative damage as well as or better than other antioxidants in a chemical (Fenton reaction) system and neuronal cultures. Cannabidiol was more protective against glutamate neurotoxicity than either ascorbate or alpha-tocopherol, indicating it to be a potent antioxidant. These data also suggest that the naturally occurring, nonpsychotropic cannabinoid, cannabidiol, may be a potentially useful therapeutic agent for the treatment of oxidative neurological disorders such as cerebral ischemia.

Animals↗
PubMed1998

Increased mortality, blunted production of nitric oxide, and increased production of TNF-alpha in endotoxemic TGF-beta1 transgenic mice.

The expression of the inducible isoform of nitric oxide synthase (NOS2, iNOS) is increased in patients undergoing sepsis as well as in animal models in which septic shock is induced by injection of bacterial lipopolysaccharide (LPS). Transforming growth factor-beta1 (TGF-beta1) potently suppresses NO production both in vitro and in vivo. After intraperitoneal injection of LPS, mice over-expressing a cDNA coding for active TGF-beta1 in the liver (Alb/ TGF-beta1) exhibited reduced serum levels of the NO reaction products NO2(-) + NO3(-) compared with controls. Paradoxically, while endotoxemic Alb/ TGF-beta1 mice expressed much less NOS2 protein in peritoneal exudate cells than did endotoxemic wild-type mice, Alb/TGF-beta1 mice expressed more NOS2 mRNA and protein in both liver and kidney. Alb/ TGF-beta1 mice treated with LPS had eightfold higher serum tumor necrosis factor alpha (TNF-alpha) levels and experienced increased mortality compared with wild-type mice, which was associated with renal insufficiency. These results suggest that renal dysfunction, decreased production of NO, and/or increased production of TNF-alpha are associated with increased mortality of endotoxemic Alb/TGF-beta1 mice.

Alanine Transaminase↗
PubMed1997

The nitric oxide/superoxide assay. Insights into the biological chemistry of the NO/O-2. interaction.

Nitric oxide (NO) is a widespread signaling molecule involved in the regulation of an impressive spectrum of diverse cellular functions. Superoxide anions (O-2) not only contribute to the localization of NO action by rapid inactivation, but also give rise to the formation of the potentially toxic species peroxynitrite (ONOO-) and other reactive nitrogen oxide species. The chemistry and biological effect of ONOO- depend on the relative rates of formation of NO and O-2. However, the simultaneous quantification of NO and O-2 has not been achieved yet due to their high rate of interaction, which is almost diffusion-controlled. A sensitive spectrophotometric assay was developed for the simultaneous quantification of NO and O-2 in aqueous solution that is based on the NO-induced oxidation of oxyhemoglobin (oxyHb) to methemoglobin and the O-2-mediated reduction of ferricytochrome c. Using a photodiode array photometer, spectral changes of either reaction were analyzed, and appropriate wavelengths were identified for the simultaneous monitoring of absorbance changes of the individual reactions. oxyHb oxidation was followed at 541.2 nm (isosbestic wavelength for the conversion of ferri- to ferrocytochrome c), and ferricytochrome c reduction was followed at 465 nm (wavelength at which absorbance changes during oxyHb to methemoglobin conversion were negligible), using 525 nm as the isosbestic point for both reactions. At final concentrations of 20 microM ferricytochrome c and 5 microM oxyHb, the molar extinction coefficients were determined to be epsilon465-525 = 7.3 mM-1 cm-1 and epsilon541.2-525 = 6.6 mM-1 cm-1, respectively. The rates of formation of either NO or O-2 determined with the combined assay were virtually identical to those measured with the classical oxyhemoglobin and cytochrome c assays, respectively. The assay was successfully adapted to either kinetic or end point determination in a cuvette or continuous on-line measurement of both radicals in a flow-through system. Maximal assay sensitivity was approximately 25 nM for NO and O-2. Cross-reactivity with ONOO- was controlled for by the presence of L-methionine. Generation of NO from the NO donor spermine diazeniumdiolate could be reliably quantified in the presence and absence of low, equimolar, and high flux rates of O-2. Likewise, O-2 enzymatically generated from hypoxanthine/xanthine oxidase could be specifically quantified with no difference in absolute rates in the presence or absence of concomitant NO generation at different flux rates. Nonenzymatic decomposition of 3-morpholinosydnonimine hydrochloride (100 microM) in phosphate buffer, pH 7.4 (37 degrees C), was found to be associated with almost stoichiometric production of NO and O-2 (1.24 microM NO/min and 1.12 microM O-2/min). Assay selectivity and applicability to biological systems were demonstrated in cultured endothelial cells and isolated aortic tissue using calcium ionophore and NADH for stimulation of NO and O-2 formation, respectively. Based on these data, a computer model was elaborated that successfully predicts the reaction of NO and O-2 with hemoprotein and may thus help to further elucidate these reactions. In conclusion, the nitric oxide/superoxide assay allows the specific, sensitive, and simultaneous detection of NO and O-2. The simulation model developed also allows the reliable prediction of the reaction between NO and O-2 as well as their kinetic interaction with other biomolecules. These new analytical tools will help to gain further insight into the physiological and pathophysiological significance of the formation of these radicals in cell homeostasis.

Cytochrome c Group↗
PubMed1997

Bicycle-spoke injuries: a prospective study.

A prospective study of bicycle-spoke injuries was undertaken to assess the severity of soft tissue damage and the incidence of skeletal injuries. During a 12 month period, 59 children with spoke injuries were examined. Soft tissue damage was divided into three categories: bruising without laceration (four), bruising and superficial abrasions (49) and full thickness skin defects (six). Seventeen children had skeletal injuries: nine tibial fractures (five greenstick fractures and four spiral fractures) and eight epiphyseal injuries of the distal fibula. All fractures were treated non-operatively. The mean time for soft tissue healing was 16.5 days and the mean time for regaining full weight-bearing was 8.5 days. Soft tissue damage is the most important prognostic factor in the healing of a bicycle-spoke injury.

Ankle Injuries↗
PubMed1995

Effects of superoxide on nitric oxide-dependent N-nitrosation reactions.

Recent studies have demonstrated that nitric oxide (NO) in the presence of superoxide (O2-) may mediate mutagenesis via the N-nitrosation of DNA bases followed by nitrosative deamination to yield their hydroxylated derivatives. We have found that phorbol myristate acetate (PMA)-activated extravasated rat neutrophils (PMNs) will N-nitrosate 2,3-diaminonaphthalene (DAN) to yield its highly fluorescent nitrosation product 2,3-naphthotriazole (triazole) via the L-arginine dependent formation of NO. Addition of SOD enhanced triazole formation suggesting that O2- production may inhibit the N-nitrosating activity and thus the mutagenic activity of inflammatory PMNs. The objective of this study was to assess the role of superoxide as a modulator of NO-dependent N-nitrosation reactions using PMA-activated PMNs as well as a chemically defined-system that generates both NO and superoxide. We found that PMA-activation of PMNs reduced found that PMA-activation of PMNs reduced the amount of N-nitrosation of DAN by approximately 64% when compared to non-stimulated cells (450 vs. 1250 nM). Addition of SOD but not inactivated SOD or catalase to PMA-activated PMNs enhanced the formation of triazole by approximately 4-fold (1950 nM). In addition, we found that the NO-releasing spermine/NO adduct (Sp/NO; 50 microM) which produces approximately 1.0 nmol NO/min generated approximately 8000 nM of triazole whereas the combination of Sp/NO and a superoxide generator (hypoxanthine/xanthine oxidase) that produces approximately 1.0 nmol O2-/min reduced triazole formation by 90% (790 nM). Addition of SOD but not catalase restored the N-nitrosating activity. We conclude that equimolar fluxes of superoxide react rapidly with NO to generate products that have only limited ability to N-nitrosate aromatic amino compounds and thus may have limited ability to promote mutagenesis via the nitrosative deamination of DNA bases.

2-Naphthylamine↗
PubMed1992

Role of nitric oxide in NMDA-evoked release of [3H]-dopamine from striatal slices.

Evidence that excitatory amino acids act via N-methyl-D-aspartate (NMDA) receptors to evoke the release of catecholamines from axonal terminals and synaptosomes has been used to argue for the presence of pre-synaptic NMDA receptors. NMDA receptor agonists also generate nitric oxide (NO) which rapidly diffuses through neural tissue. We find that exogenously applied NO evokes [3H]-dopamine release from cultured neurons. This release is not blocked by the NMDA antagonist MK-801 nor by tetrodotoxin. Both NG-nitroarginine which inhibits NO synthesis, and hemoglobin which binds extracellular NO, block NMDA-evoked [3H]-dopamine release from striatal slices. A major role of endogenously-synthesized NO may be to evoke neurotransmitter release in local volumes of neural tissue.

Animals↗