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S Barnes

Publications and source records attributed to S Barnes.

At least 55 records · Page 3Linked to original sources
PubMed2000

Assessing phytoestrogen exposure in epidemiologic studies: development of a database (United States).

BACKGROUND AND OBJECTIVE: Phytoestrogens (weak estrogens found in plants or derived from plant precursors by human metabolism) have been hypothesized to reduce the risk of a number of cancers. However, epidemiologic studies addressing this issue are hampered by the lack of a comprehensive phytoestrogen database for quantifying exposure. The purpose of this research was to develop such a database for use with food-frequency questionnaires in large epidemiologic studies. METHODS: The database is based on consumption patterns derived from semistructured interviews with 118 African-American, Latina, and white women residing in California's San Francisco Bay Area. HPLC-mass spectrometry was used to determine the content of seven specific phytoestrogenic compounds (i.e. the isoflavones: genistein, daidzein, biochanin A, and formononetin; the coumestan: coumestrol; and the plant lignans: matairesinol and secoisolariciresinol) in each of 112 food items/groups. RESULTS: Traditional soy-based foods were found to contain high levels of genistein and daidzein, as expected, as well as substantial amounts of coumestrol. A wide variety of "hidden" sources of soy (that is, soy protein isolate, soy concentrate, or soy flour added to foods) was observed. Several other foods (such as various types of sprouts and dried fruits, garbanzo beans, asparagus, garlic, and licorice) were also found to be substantial contributors of one or more of the phytoestrogens analyzed. CONCLUSIONS: Databases, such as the one described here, are important in assessing the relationship between phytoestrogen exposure and cancer risk in epidemiologic studies. Agencies, such as the United States Department of Agriculture (USDA), that routinely provide data on food composition, on which epidemiologic investigations into dietary health effects are based, should consider instituting programs for the analysis of phytochemicals, including the phytoestrogens.

Adult↗
PubMed2000

Sterile sheets? The importance of preadmission interviews.

The goals of the preadmission interview are to meet the physical, emotional, and educational needs of the patient and to facilitate the admissions process. The information provided to the patient during this contact enhances both patient and staff satisfaction.

Bedding and Linens↗
PubMed2000

Are you watching the clock? Let criteria define discharge readiness.

The primary function of the perianesthesia team is to assure that physically stable individuals are sent home with the necessary education and preparation for the transition to self-care. The use of discharge criteria provides a safe and efficient process for this transition.

Ambulatory Surgical Procedures↗
PubMed2000

Not a social event: the follow-up phone call.

The follow-up phone call provides an invaluable opportunity to evaluate patient education, identify trends that may require improvement in practice, determine compliance with discharge instructions, and assess overall impressions of performance. This process supports efforts to "close the loop" on patient contact.

Ambulatory Surgical Procedures↗
PubMed2000

Domestic violence: the shaken adult syndrome.

A case of domestic violence is reported. The patient presented with the triad of injuries associated with the shaking of infants: retinal haemorrhages, subdural haematoma, and patterned bruising; this has been described as the shaken adult syndrome. This case report reflects the difficulties in diagnosing domestic violence in the accident and emergency setting.

Adult↗
PubMed2000

Calcium channel activation facilitated by nitric oxide in retinal ganglion cells.

We investigated the modulation of voltage-gated Ca channels by nitric oxide (NO) in isolated salamander retinal ganglion cells with the goals of determining the type of Ca channel affected and the signaling pathway by which modulation might occur. The NO donors, S-nitroso-N-acetyl-penicillamine (SNAP, 1 mM) and S-nitroso-cysteine (1 mM) induced modest increases in the amplitude of Ca channel currents recorded with ruptured- and permeabilized-patch techniques by causing a subpopulation of the Ca channels to activate at more negative potentials. The Ca channel antagonists omega-conotoxin GVIA and nisoldipine each reduced the Ca channel current partially, but only omega-conotoxin GVIA blocked the enhancement by SNAP. The SNAP-induced increase was blocked by oxadiazolo-quinoxaline (50 microM), suggesting that the NO generated by SNAP acts via a soluble guanylyl cyclase to raise levels of cGMP. The membrane-permeant cGMP analog 8-(4-chlorophenylthio) guanosine cyclic monophosphate also enhanced Ca channel currents and 8-bromo guanosine cyclic monophosphate (1 mM) occluded enhancement by SNAP. Consistent with these results, isobutyl-methyl-xanthine (IBMX, 10 microM), which can raise cGMP levels by inhibiting phosphodiesterase activity, increased Ca channel current by the same amount as SNAP and occluded subsequent enhancement by SNAP. Neither IBMX, the cGMP analogs, nor SNAP itself, led to activation of cGMP-gated channels. N-[2-(methylamino)ethyl]-5-isoquinoline-sulfonamide (2 microM), a broad spectrum inhibitor of protein kinase activity, KT5823 (1 microM), a specific protein kinase G (PKG) inhibitor, and a peptide inhibitor of PKG (200 microM) blocked SNAP enhancement, as did 5'-adenylylimidophosphate (1.5 mM), a nonhydrolyzable ATP analog that prevents protein phosphorylation. A peptide inhibitor of protein kinase A (10 nM) did not block the facilitory effects of SNAP. Okadaic acid (1 microM), a phosphatase inhibitor, had no effect by itself but increased the enhancement of Ca channel current by SNAP. These results suggest that NO modulates retinal ganglion cell N-type Ca channels by facilitating their voltage-dependent activation via a mechanism involving guanylyl cyclase/PKG-dependent phosphorylation. This effect could fine-tune neural integration in ganglion cells or play a role in ganglion cell disease by modulating intracellular calcium signaling.

1-Methyl-3-isobutylxanthine↗
PubMed2000

Depolarization-induced calcium channel facilitation in rod photoreceptors is independent of G proteins and phosphorylation.

Depolarization-induced facilitation of L-type Ca channels in rod photoreceptors was investigated with nystatin-perforated and ruptured whole cell patch-clamp techniques in cells isolated from tiger salamander retina. Induction of facilitation was voltage dependent with a half-maximal effect seen at prepulse potentials near +31 mV. Reversal of facilitation was time dependent with fast (tau approximately 20 ms) and slow (tau approximately 1 s) components at -60 mV. Incubation of cells with pertussis toxin or intracellular administration of guanosine 5'-O-(3-thiotriphosphate) or guanosine 5'-O-(2-thiodiphosphate) had no effect on the degree to which facilitation could be evoked, implying the absence of a significant role for G proteins. Application of the phosphatase inhibitor okadaic acid or inclusion of ATP, to boost levels of phosphorylation, or inclusion of 5'adenylylimidophosphate or inhibitors of protein kinase in the pipette, to reduce levels of phosphorylation, had no effect on the development of facilitation, suggesting that phosphorylation has little or no role in this phenomenon. These results show that the L-type Ca channels in rod photoreceptors, which appear to be composed of alpha(1F)-like subunits, undergo voltage-dependent facilitation in a manner that differs from some other L-type Ca channels which undergo facilitation via phosphorylation or through G-protein-mediated inhibition.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed2000

Eosinophilic angiocentric fibrosis.

Eosinophilic angiocentric fibrosis (EAF) is a rare inflammatory fibrosing condition of unknown aetiology that involves the nose or larynx producing mucosal thickening and severe obstructive symptoms. We report the first case affecting a male. He presented with nasal obstruction requiring septoplasty. The clinical and histopathological features of the condition are discussed and a comparison is made with the seven previous reported cases.

Eosinophilia↗
PubMed1999

Chlorination and nitration of soy isoflavones.

Diets enriched in soy foods containing a high concentration of isoflavonoids are associated with a decrease in the incidence of several chronic inflammatory diseases. Studies with experimental models of diseases, such as atherosclerosis, suggest that these effects can be ascribed to the biological properties of the isoflavones. Since the isoflavones and tyrosine have structural similarities and modifications to tyrosine by inflammatory oxidants such as hypochlorous acid (HOCl) and peroxynitrite (ONOO(-)) have been recently recognized, we hypothesized that the isoflavones also react with HOCl and ONOO(-). Using an in vitro approach, we demonstrate in the present study that the isoflavones genistein, daidzein, and biochanin-A can be chlorinated and nitrated by these oxidants. These reactions were investigated using high-performance liquid chromatography, mass spectrometry, and nuclear magnetic resonance. In the reaction with HOCl, both mono- and dichlorinated derivatives of genistein and biochanin-A are formed, whereas with daidzein only a monochlorinated derivative was detected. The reaction between genistein or daidzein and ONOO(-) yielded a mononitrated product. However, no nitrated product was detected with biochanin-A. Furthermore, the reaction between genistein and sodium nitrite and HOCl yielded a chloronitrogenistein derivative, as well as a dichloronitrogenistein derivative. These results indicate that the ability of the isoflavones to react with these oxidant species depends on their structure and suggest that they could be formed under conditions where these reactive species are generated under pathological conditions.

Chromatography, High Pressure Liquid↗
PubMed1999

Nitration of unsaturated fatty acids by nitric oxide-derived reactive species.

Reactions of linoleate (and presumably other unsaturated fatty acids) with reactive nitrogen species that form in biological systems from secondary reactions of .NO yield two main nitration product groups, LNO2 (formed by ONOO-, .NO2, or NO2+ reaction with linoleate), and LONO2 (formed by HONO reaction with 13(S)-HPODE, or .NO termination with LOO.). Comparison of HPLC retention times and m/z for lipid nitration products indicate that the mechanisms of nitrated product formation converge at several points: (i) The initial product of HONO attack on LOOH will be LOONO, which is identical to the initial termination product of LOO. reaction with .NO. (ii) Dissociation of LOONO to give LO. and .NO2 via caged radicals, which recombine to give LONO2 (m/z 340) will occur, regardless of how LOONO is formed (Fig. 7). (iii) In some experiments, the reaction of O2- (where oxidation is initiated by xanthine oxidase-derived O2- production and metal-dependent decomposition of H2O2) with .NO will result in generation of ONOO-. Nitration of unsaturated lipid by this species will yield a species demonstrated herein to be LNO2. Lipid oxidation leads to formation of bioactive products, including hydroxides, hydroperoxides, and isoprostanes. In vivo, nitrated lipids (LNO2, LONO2) may also possess bioactivity, for example through eicosanoid receptor binding activity, or by acting as antagonists/competitive inhibitors of eicosanoid receptor-ligand interactions. In addition, nitrated lipids could mediate signal transduction via direct .NO donation, transnitrosation, or following reductive metabolism. Similar bioactive products are formed following ONOO- reaction with glucose, glycerol, and other biomolecules.

Animals↗
PubMed1999

Nitration of unsaturated fatty acids by nitric oxide-derived reactive nitrogen species peroxynitrite, nitrous acid, nitrogen dioxide, and nitronium ion.

Reactive nitrogen species derived from nitric oxide are potent oxidants formed during inflammation that can oxidize membrane and lipoprotein lipids in vivo. Herein, it is demonstrated that several of these species react with unsaturated fatty acid to yield nitrated oxidation products. Using HPLC coupled with both UV detection and electrospray ionization mass spectrometry, products of reaction of ONOO- with linoleic acid displayed mass/charge (m/z) characteristics of LNO2 (at least three products at m/z 324, negative ion mode). Further analysis by MS/MS gave a major fragment at m/z 46. Addition of a NO2 group was confirmed using [15N]ONOO- which gave a product at m/z 325, fragmenting to form a daughter ion at m/z 47. Formation of nitrated lipids was inhibited by bicarbonate, superoxide dismutase (SOD), and Fe3+-EDTA, while the yield of oxidation products was decreased by bicarbonate and SOD, but not by Fe3+-EDTA. Reaction of linoleic acid with both nitrogen dioxide (*NO2) or nitronium tetrafluoroborate (NO2BF4) also yielded nitrated lipid products (m/z 324), with HPLC retention times and MS/MS fragmentation patterns identical to the m/z 324 species formed by reaction of ONOO- with linoleic acid. Finally, reaction of HPODE, but not linoleate, with nitrous acid (HONO) or isobutyl nitrite (BuiONO) yielded a product at m/z 340, or 341 upon reacting with [15N]HONO. MS/MS analysis gave an NO2- fragment, and 15N NMR indicated that the product contained a nitro (RNO2) functional group, suggesting that the product was nitroepoxylinoleic acid [L(O)NO2]. This species could form via homolytic dissociation of LOONO to LO* and *NO2 and rearrangement of LO* to an epoxyallylic radical L(O)* followed by recombination of L(O)* with *NO2. Since unsaturated lipids of membranes and lipoproteins are critical targets of reactive oxygen and nitrogen species, these pathways lend insight into mechanisms for the formation of novel nitrogen-containing lipid products in vivo and provide synthetic strategies for further structural and functional studies.

Chromatography, High Pressure Liquid↗
PubMed1999

Manipulation of synaptic sign and strength with divalent cations in the vertebrate retina: pushing the limits of tonic, chemical neurotransmission.

At the first synaptic level of the vertebrate retina, photoreceptor light responses are transmitted to second order neurones through a chemical synapse based on a tonic release of neurotransmitter modulated by graded changes of presynaptic potential. The possibility that such synapses could work through a Ca2+-independent process had been proposed by previous authors, based on the persistence of transmission process in low Ca2+ media containing Co2+ or Ni2+ ions. Recently, we were able to explain these results within the framework of the classical calcium-hypothesis of synaptic transmission by taking into account the modifications of presynaptic surface potential brought about by changes of divalent cation concentrations. Here we report data showing how a surface-charge hypothesis could account for several apparently paradoxical effects of divalent cation manipulations such as: the enhancement of neurotransmitter release induced by low Ca2+ media; the transmission "unblocking" effect of Zn2+, Co2+ and Ni2+; and the reversal of transmission polarity induced by application of low Ca2+ media containing Cd2+ or Mg2+ ions.

Ambystoma↗
PubMed1999

Serum vitellogenin levels and reproductive impairment of male Japanese Medaka (Oryzias latipes) exposed to 4-tert-octylphenol.

The induction of synthesis of the "female" yolk precursor protein vitellogenin (VTG) in male fish by estrogenic chemicals in the environment has been demonstrated in many recent reports. However, little is known about the organismal and biological significance of this phenomenon. To examine the relationship between VTG production in male fish and reproductive impairment, adult male medaka were exposed to 4-tert-octylphenol (OP), a known environmental estrogen, in concentrations ranging from 20 to 230 ppb for 21 days, under flow-through conditions. Following exposure, male fish were mated, in the absence of OP, with unexposed females. Breeding groups composed of exposed males and control females produced about 50% fewer eggs than control groups. VTG levels in serum of male fish increased with increasing OP exposure concentration and decreased after OP exposure was discontinued. Nevertheless, significant correlations (p<0.01) were observed between VTG levels in exposed male fish and 1) OP exposure concentrations, 2) percent of fertilized eggs, and 3) survival of embryos. OP-induced VTG synthesis and reproductive impairment appear to be closely linked phenomena. Histological examination indicated spermatogenesis in OP-exposed fish was inhibited, and some exposed fish had oocytes in their testes. Finally, OP caused a significant increase in the number of abnormally developing embryos, suggesting that OP may be genotoxic as well as estrogenic.

Animals↗
PubMed1999

The impact of renal dysfunction on aprotinin pharmacokinetics during cardiopulmonary bypass.

UNLABELLED: Aprotinin is a serine protease inhibitor that undergoes metabolism in the kidney. Because elimination is almost entirely renal, the clearance of aprotinin may be reduced in patients with renal insufficiency. Unfortunately, there are no data regarding aprotinin pharmacokinetics in cardiac surgical patients with renal insufficiency or end-stage renal disease (ESRD) undergoing cardiopulmonary bypass (CPB). We, therefore, determined the clearance (ApCl) and elimination half-life (T1/2) of aprotinin in 26 cardiac surgical patients with normal and abnormal renal function (creatinine clearance [CrCl] 0-122 mL/min) undergoing CPB. Subjects were given a 2 million kallikrein inhibiting unit (KIU) initial dose of aprotinin, followed by a 0.25 million KIU/h infusion. No aprotinin was added to the pump prime. Plasma aprotinin concentrations were sampled at 30 min after completion of the loading dose, 30 and 60 min after the onset of CPB, at the end of CPB, and at 8, 24, and 32 h after completion of the loading dose. ApCl was directly related and the elimination T1/2 inversely related to CrCl (r = 0.75 and 0.42, respectively). In patients with a CrCl >50 mL/min, the T1/2 and ApCl were 7.8 h and 53 mL/min, respectively, compared with 19.9 h and 25 mL/min (P < 0.05, P < 0.002, respectively) for patients with ESRD. In conclusion, ApCl is reduced, and T1/2 is prolonged in patients with renal insufficiency or ESRD undergoing CPB. Dosing modifications may be necessary for patients with abnormal renal function undergoing cardiac surgery. IMPLICATIONS: Because aprotinin is metabolized and eliminated in the kidney, its clearance may be reduced in patients with renal insufficiency. Our data suggest that aprotinin clearance is reduced, and aprotinin half-lives are prolonged in patients with renal insufficiency undergoing CPB. Dosing modification may therefore be indicated when aprotinin is administered to these patients for cardiac surgery.

Aged↗