Exacerbation of psychosis associated with inhaled albuterol.
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Administration, Inhalation↗
Biomedical subjects
W Martin
Publications and source records attributed to W Martin.
The inhibitory effect of 3-amino-1,2,4-triazole on relaxation induced by hydroxylamine and sodium azide but not hydrogen peroxide or glyceryl trinitrate in rat aorta.
1. In this study we investigated the role of catalase in relaxation induced by hydroxylamine, sodium azide, glyceryl trinitrate and hydrogen peroxide in isolated rings of rat aorta. 2. Hydrogen peroxide (1 microM-1 mM)-induced concentration-dependent relaxation of phenylephrine (PE)-induced tone in endothelium-containing rings. In endothelium-denuded rings, however, higher concentrations (30 microM-1 mM) of hydrogen peroxide were required to produce relaxation. The endothelium-dependent component of hydrogen peroxide-induced relaxation was abolished following pretreatment with N(O)-nitro-L-arginine methyl ester (L-NAME, 30 microM). L-NAME (30 microM) had no effect, however, on hydrogen peroxide-induced relaxation in endothelium-denuded rings. 3. Pretreatment of endothelium-denuded rings with catalase (1000 u ml-1) blocked relaxation induced by hydrogen peroxide (10 microM-1 mM). The ability of catalase to inhibit hydrogen peroxide-induced relaxation was partially blocked following incubation with 3-amino-1,2, 4-triazole (AT, 50 mM) for 30 min and completely blocked at 90 min. 4. Pretreatment of endothelium-denuded rings with methylene blue (MeB, 30 microM) inhibited relaxation induced by hydrogen peroxide (10 microM-1 mM), sodium azide (1-300 nM), hydroxylamine (1-300 nM) and glyceryl trinitrate (1-100 nM) suggesting that each acted by stimulation of soluble guanylate cyclase. 5. Pretreatment of endothelium-denuded rings with AT (1-50 mM, 90 min) to inhibit endogenous catalase blocked relaxation induced by sodium azide (1-300 nM) and hydroxylamine (1-300 nM) but had no effect on relaxation induced by hydrogen peroxide (10 microM-1 mM) or glyceryl trinitrate (1-100 nM). 6. In a cell-free system, incubation of sodium azide (10 microM-3 mM) and hydroxylamine (10 microM-30 mM) but not glyceryl trinitrate (10 microM-1 mM) with catalase (1000 u ml-1) in the presence of hydrogen peroxide (1 mM) led to production of nitrite, a major breakdown product of nitric oxide. AT (1-100 mM) inhibited, in a concentration-dependent manner, the formation of nitrite from azide in the presence of hydrogen peroxide. 7. These data suggest that metabolism by catalase plays an important role in the relaxation induced by hydroxylamine and sodium azide in isolated rings of rat aorta. Relaxation appears to be due to formation of nitric oxide and activation of soluble guanylate cyclase. In contrast, metabolism by catalase does not appear to be involved in the relaxant actions of hydrogen peroxide or glyceryl trinitrate.
Amitrole↗
Differential sensitivity of basal and acetylcholine-stimulated activity of nitric oxide to destruction by superoxide anion in rat aorta.
1. In this study we compared the ability of superoxide anion to destroy the relaxant activity of basal and acetylcholine (ACh)-stimulated activity of NO in isolated rings of rat aorta. 2. Superoxide dismutase (SOD, 1-300 u ml-1) induced a concentration-dependent relaxation of phenylephrine (PE)-induced tone in endothelium-containing rings which was blocked by NG-nitro-L-arginine (L-NOARG, 30 microM), but had no effect on endothelium-denuded rings. It was likely therefore that the relaxant action of SOD resulted from protection of basally produced NO from destruction by superoxide anion, generated either within the tissue or in the oxygenated Krebs solution. 3. In contrast, a concentration of SOD (50 u ml-1) which produced almost maximal enhancement of basal NO activity, had no effect on ACh (10 nM-3 microM)-induced relaxation. 4. In the presence of catalase (3000 u ml-1) to prevent the actions of hydrogen peroxide, superoxide anion generation using hypoxanthine (HX, 0.1 mM)/xanthine oxidase (XO, 16 mu ml-1) produced an augmentation of PE-induced tone in endothelium-containing but not endothelium-denuded rings. This was likely to have resulted from removal of the tonic vasodilator action of basally-produced NO by superoxide anion, since it was blocked in tissues treated with SOD (250 u ml-1), NG-monomethyl-L-arginine (L-NMMA, 30 microM) or L-NOARG (30 microM). Pyrogallol (0.1 mM) had a similar action to HX/XO, but produced an additional augmentation of tone by an endothelium-independent mechanism. 5. In contrast to their ability to destroy almost completely the basal activity of NO, HX (0.1 mM)/XO(16 mu ml-1) and pyrogallol (0.1 mM) had no effect on ACh-induced relaxation at any concentration. An increase in the concentration of HX to 1 mM or pyrogallol to 0.3 mM did, however, lead to a profound decrease in the magnitude and time course of ACh-induced relaxation at all concentrations.6. Treatment with diethyldithiocarbamate (DETCA, 0.1 mM, 1 h) to inhibit endogenous Cu-Zn SOD,augmented PE-induced tone in endothelium-containing rings and abolished the ability of HX (0.1 mM)/XO (16 mu ml-1) and L-NMMA (30 microM) to augment tone. It was likely that DETCA had led to the destruction of basal NO activity by increasing superoxide anion levels since its actions were reversed by exogenous SOD (10-300 upsilon ml-1).7. In contrast to its ability to destroy basal activity of NO completely, DETCA (0.1 mM) produced only a slight blockade of ACh-induced relaxation. However, if these tissues were subsequently treated with concentrations of HX (0.1 mM)/XO (16 mu ml-1) or pyrogallol (0.1 mM), which had no effect by themselves on ACh-induced relaxation, a profound blockade was seen and this was reversed completely with SOD (250 u ml-1).8. The data suggest that basal activity of NO is more sensitive to inactivation by superoxide anion than ACh-stimulated activity and this probably results from differential protection by endogenous Cu-ZnSOD. It is possible therefore that endogenous SOD lowers superoxide anion levels to such an extent that only small amounts of NO, such as those produced under basal conditions, are destroyed. Following generation of superoxide anion with HX/XO or pyrogallol, or inhibition of Cu-Zn SOD with DETCA,levels of the free radical will increase such that greater amounts of NO, such as those produced following stimulation with ACh, will then be destroyed.
Acetylcholine↗
Do radionuclide and echocardiographic techniques give a universal cut off value for left ventricular ejection fraction that can be used to select patients for treatment with ACE inhibitors after myocardial infarction?
OBJECTIVE: To determine whether echocardiography and radionuclide angiography give comparable results when the left ventricular ejection fraction is measured early after myocardial infarction and thus whether, irrespective of the method used, a single value for the ejection fraction could be used as a guide for starting treatment with an angiotensin converting enzyme inhibitor. DESIGN: Prospective comparison of measurement of left ventricular ejection fraction by echocardiography and radionuclide angiography. SETTING: Coronary care units of two university teaching hospitals in Glasgow. PATIENTS: 99 patients studied within 36 hours of acute myocardial infarction. OUTCOME MEASURES: Left ventricular ejection fraction assessed by echocardiography and radionuclide angiography. RESULTS: 70 (77%) of the 99 patients had ejection fraction measured by both echocardiographic and radionuclide techniques, 30 in centre 1 and 40 in centre 2. In centre 1 the mean difference (SD) in ejection fraction (radionuclide angiography--echocardiography) was -8 (10%); 95% CI -12 to -4%. In centre 2 the mean difference was -14 (11%); 95% CI -17 to -11%. If patients had been treated with an ACE inhibitor on the basis of a radionuclide ejection fraction of < 40% then 93% in centre 1 (28 of 30) and 98% in centre 2 (39 of 40) would have been treated. This compares with 63% (19 of 30) and 50% (20 of 40), respectively if echocardiography had been used as a guide. CONCLUSION: Measurement of ejection fraction is highly dependent on the method used and it is therefore impossible to quote a universally applicable figure for left ventricular ejection fraction below which an ACE inhibitor should be used after myocardial infarction.
Angiotensin-Converting Enzyme Inhibitors↗
[TULIP (transurethral ultrasound-controlled laser-induced prostatectomy)--experiences with over 80 patients].
Of the many methods currently under investigation for the treatment of symptomatic and obstructive benign prostatic hyperplasia (BPH), laser treatment seems the most likely to yield results comparable to those achieved with transurethral resection of the prostate (TURP). Between May 1991 and December 1993 a total of 83 men were treated in our department with the TULIP (transurethral ultrasound-guided laser-induced prostatectomy) device. Within the first year of follow-up there was a marked improvement in both signs and symptoms. The average urinary peak flow increased from 6 to 16 ml/s, the residual urine volume decreased from 218 ml to 36 ml, and the symptom score (assessed against a modified Boyarsky score) decreased from 17 to 4 points. Our experience so far indicates that the advantages of TULIP are minimal blood loss, no post-transurethral resection syndrome, and a low rate of retrograde ejaculation postoperatively. In addition, the procedure can be performed with analgosedation. Disadvantages are the delayed onset of improvement, combined with irritative symptoms in the early weeks after the procedure. In addition, no tissue can be obtained for histological examination, which may be important in the long-term. Randomized prospective studies, including cost-benefit analyses, are needed to check for advantages of TULIP over TURP.
Aged↗
[Bottle feeding of an infant--didactic concept of the preparation and execution of bottle feeding for a newborn].
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Bottle Feeding↗
[Aneurysm of the hepatic artery as the cause of acute abdomen and liver infarct caused by vascular compression].
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Abdomen, Acute↗
Five identical intron positions in ancient duplicated genes of eubacterial origin.
In 1985 Cornish-Bowden wrote "although there is now much to suggest that introns are an ancient relic of primordial genes, convincing proof must await the discovery of clearly corresponding intron arrangements in genes that arose by duplication before the separation of prokaryotes and eukaryotes". Genes for chloroplast and cytosolic glyceraldehyde-3-phosphate dehydrogenases of eukaryotes are descendants of an ancient gene family that existed in the common ancestor of extant eubacteria. During eukaryotic evolution, both genes were transferred to the nucleus from the antecedents of present-day chloroplasts and mitochondria, respectively. Here we report the discovery of five spliceosomal introns at positions that are precisely conserved between nuclear genes for this chloroplast/cytosol enzyme pair. These data provide strong evidence in favour of the 'introns early' hypothesis, which proposes that introns were present in the earliest cells, consistent with the idea that introns facilitated the assembly of primordial genes by accelerating the rate of exon shuffling.
Amino Acid Sequence↗
Chloroplast and cytosolic triosephosphate isomerases from spinach: purification, microsequencing and cDNA cloning of the chloroplast enzyme.
Chloroplast and cytosolic triosephosphate isomerases from spinach were separated and purified to homogeneity. Both enzymes were partially sequenced by Edman degradation. Using degenerate primers designed against the amino acid sequences, a homologous probe for the chloroplast enzyme was amplified and used to isolate several full-size cDNA clones. Chloroplast triosephosphate isomerase is encoded by a single gene in spinach. Analysis of the chloroplast cDNA sequence in the context of its homologues from eukaryotes and eubacteria reveals that the gene arose through duplication of its preexisting nuclear counterpart for the cytosolic enzyme during plant evolution.
Amino Acid Sequence↗
Molecular characterization of a novel, nuclear-encoded, NAD(+)-dependent glyceraldehyde-3-phosphate dehydrogenase in plastids of the gymnosperm Pinus sylvestris L.
Angiosperms and algae possess two distinct glyceraldehyde-3-phosphate dehydrogenase (GAPDH) enzymes, an NAD(+)-dependent tetramer involved in cytosolic glycolysis and an NADP(+)-dependent enzyme of the Calvin cycle in chloroplasts. We have found that the gymnosperm Pinus sylvestris possesses, in addition to these, a nuclear-encoded, plastid-specific, NAD(+)-dependent GAPDH, designated GapCp, which has not previously been described from any plant. Several independent full-size cDNAs for this enzyme were isolated which encode a functional transit peptide and mature subunit very similar to that of cytosolic GAPDH of angiosperms and algae. A molecular phylogeny reveals that chloroplast GapCp and cytosolic GapC arose through gene duplication early in chlorophyte evolution. The GapCp gene is expressed as highly as that for GapC in light-grown pine seedlings. These findings suggest that aspects of compartmentalized sugar phosphate metabolism may differ in angiosperms and gymnosperms and furthermore underscore the contributions of endosymbiotic gene transfer and gene duplication to the nuclear complement of genes for enzymes of plant primary metabolism.
Amino Acid Sequence↗
The evolutionary origin of red algae as deduced from the nuclear genes encoding cytosolic and chloroplast glyceraldehyde-3-phosphate dehydrogenases from Chondrus crispus.
Algae are a heterogeneous group of photosynthetic eukaryotes traditionally separated into three major subdivisions: rhodophytes, chlorophytes, and chromophytes. The evolutionary origin of rhodophytes or red algae and their links to other photosynthetic and nonphotosynthetic eukaryotes have been a matter of much controversy and speculation. Here we present the first cDNAs of nuclear protein genes from red algae: Those encoding cytosolic and chloroplast glyceraldehyde-3-phosphate dehydrogenases (GAPDH) from Chondrus crispus. A phylogenetic analysis including GAPDH gene sequences from a number of eukaryotic taxa, cyanobacteria, and purple bacteria suggests that chloroplasts and rhodoplasts together form a monophyletic group of cyanobacterial descent and that rhodophytes separated from chlorophytes at about the same time as animals and fungi. The composite GAPDH tree further demonstrates that chloroplast and cytosolic GAPDH genes are closely related to their homologs in cyanobacteria and purple bacteria, respectively, the presumptive ancestors of chloroplasts and mitochondria, thereby firmly establishing the endosymbiotic origin of these nuclear genes and their fixation in eukaryotic cells before the rhodophyte/chlorophyte separation. The present data are in conflict with phylogenetic inferences based on plastid-encoded rbcL sequences supporting a polyphyletic origin of rhodoplasts and chloroplasts. Comparison of rbcL to GAPDH phylogenies suggests that rbcL trees may be misleading because they are composed of branches representing ancient duplicated (paralogous) genes.
Amino Acid Sequence↗
Nucleotide distribution in gymnosperm nuclear sequences suggests a model for GC-content change in land-plant nuclear genomes.
Nuclear protein coding sequences from gymnosperms are currently scarce. We have determined 4 kb of nuclear protein coding sequences from gynosperms and have collected and analyzed > 60 kb of nuclear sequences from gymnosperms and nonspermatophytes in order to better understand processes influencing genome evolution in plants. We show that conifers possess both biased and nonbiased genes with respect to GC content, as found in monocots, suggesting that the common ancestor of conifers and monocots may have possessed both biased and nonbiased genes. The lack of biased genes in dicots is suggested to be a derived character for this lineage. We present a simple but speculative model of land-plant genome evolution which considers changes in GC bias and CpG frequency, respectively, as independent processes and which can account for several puzzling aspects of observed nucleotide frequencies in plant genes.
Base Composition↗
NANC neurotransmission in the bovine retractor penis muscle is blocked by superoxide anion following inhibition of superoxide dismutase with diethyldithiocarbamate.
This study examined the effects of inhibiting Cu/Zn superoxide dismutase with diethyldithiocarbamate (DETCA) on the ability of superoxide generating agents such as pyrogallol, hypoxanthine/xanthine oxidase and LY 83583, to influence NANC relaxation of strips of bovine retractor penis (BRP) muscle. Although pyrogallol (100 microM) and hypoxanthine (0.3 mM)/xanthine oxidase (64 mU ml-1) had little effect on NANC relaxation in control strips, both induced almost complete inhibition following treatment with DETCA (3 mM) for 1 h. Inhibition was due to the actions of superoxide anion since it was blocked by the addition of exogenous superoxide dismutase (250 U ml-1). LY 83583 (0.1-30 microM) produced a concentration-dependent inhibition of NANC relaxation even in control strips and this too was blocked by exogenous superoxide dismutase, but sensitivity to inhibition was enhanced 10-fold following treatment with DETCA. The data suggest that under normal circumstances the NANC neurotransmitter is protected by high levels of tissue superoxide dismutase, and inhibition of this enzyme increases its susceptibility to destruction by superoxide anions. An important impediment to accepting free nitric oxide as the NANC neurotransmitter in the BRP on the basis that superoxide anion-generating agents inhibit the actions of authentic nitric oxide but not those of NANC nerve stimulation has thus been removed.
Aminoquinolines↗
Dehydration: a model for (low-temperature) argon laser tissue bonding.
Despite considerable investigation, the mechanism of laser assisted vascular anastomosis remains unknown. Indications suggest that bonding is the result of thermal action, particularly the thermal denaturation of tissue proteins. However, our own work has led us to conclude that dehydration is an important factor. Hence, we have proposed that laser anastomosis is the result of dehydration at the apposed tissue faces, induced by laser irradiation. This was investigated by comparing the properties of bonds created by dehydration with those created by laser. The bonds were created using parameters consistent with laser anastomoses created in vivo. Results revealed that anastomoses created by dehydration were equivalent to those created by laser, with little difference in strength, histology or response to rehydration. The only significant difference (p < 0.02) was mean bond strength created at temperatures above the denaturation temperature of the tissue (548 g cm(-2) by laser, 994 g cm(-2) by dehydration). Given the similarity of bonds created by the two methods, we conclude that the same mechanism (i.e. dehydration) is likely to be responsible for bonding in both cases and therefore that argon laser bonding is mediated by dehydration.
Anastomosis, Surgical↗
A comparison of adenosine and exercise stress 201T1 scintigraphy.
A detailed comparison of stress thallium images utilizing exercise (symptom-limited bicycle ergonometer) and adenosine (infused at 50 micrograms kg-1 min-1 increasing by 25 micrograms kg-1 min-1 every 2 min to a maximum tolerated dose) was performed in 20 patients with angiographically documented coronary disease. Ten patients were receiving beta-blockade at the time of both tests. Triple-, double- and single-vessel disease was present in eight, seven and five patients, respectively. Exercise produced a large increase in double product (8970 +/- 288 to 20,-984 +/- 690 mm Hg min-1) while adenosine produced no significant change (8440 +/- 280 to 9086 +/- 600 mm Hg min-1). Each of the three gated planar images (anterior 40 degrees and 70 degrees left anterior oblique) was divided into five equal segments. Exercise produced 44/90, 44/95 and 45/95 abnormal segments in the anterior, 40 degrees and 70 degrees views while adenosine produced 53/100, 44/100 and 52/100 abnormal segments for the same views. The total number of abnormal segments was similar in both groups (133/280 exercise and 149/300 adenosine). Each abnormal segment was analysed for degree of change between stresses using a five-point scoring system. Exercise produced eight segments which were larger by one point and 44 segments larger by two points while adenosine produced 17 and 44 segments larger by one and two points respectively. Left ventricular uptake (as % injected dose) was significantly greater in the adenosine group (1.12 +/- 0.06% versus 0.64 +/- 0.05%, P < 0.01) but right ventricular uptake was similar (0.15 +/- 0.1% versus 0.14 +/- 0.09%).(ABSTRACT TRUNCATED AT 250 WORDS)
Adenosine↗
Non-adrenergic, non-cholinergic relaxation of the bovine retractor penis muscle: role of S-nitrosothiols.
1. This study examined the possibility that an S-nitrosothiol, rather than nitric oxide, functions as the non-adrenergic, non-cholinergic (NANC) inhibitory neurotransmitter in the bovine retractor penis (BRP) muscle. 2. Treatment of BRP muscle with either of two sulphydryl inactivating agents, diamide (1 mM) and N-ethylmaleimide (0.3 mM), inhibited NANC relaxation and this was prevented by pretreating tissues with L-cysteine (3 mM), L-glutathione (3 mM) or dithiothreitol (3 mM). Inhibition was not specific, however, since the inactivating agents also inhibited the relaxant actions of authentic nitric oxide (0.3 microM), glyceryl trinitrate (0.001-1 microM) and isoprenaline (0.01-1 microM). 3. Reacting nitric oxide with L-cysteine in nominally oxygen-free solution at pH 3, followed by purging to remove free nitric oxide and neutralisation, produced greater and more prolonged relaxant activity when assayed on rabbit aortic rings than could be attributed to nitric oxide alone. H.p.l.c. analysis of the mixture identified a new peak distinct from either L-cysteine or nitric oxide which was responsible for the relaxant activity. The spectral absorption of this new compound had two bands with peaks at 218 and 335 nm. 4. Using a series of structural analogues of L-cysteine (all at 15 mM) it was found that removal of the carboxyl group (L-cysteamine), replacement of the carboxyl with an ester function (L-cysteine methyl ester) or substitution at the amino group (N-acetyl-L-cysteine) had no effect on the ability to generate relaxant activity upon reaction with nitric oxide (0.1 mM). In contrast, substitution at the sulphydryl group (S-methyl-L-cysteine, L-cysteinesulfinic acid and L-cysteic acid), or formation of disulphides(L-cystine and L-cystamine) led to a complete loss of ability to generate relaxant activity. L-Glutathione was also able to react with nitric oxide to produce relaxant activity, and this too was blocked upon substitution of the free sulphydryl group (S-methyl-L-glutathione). A free sulphydryl group was therefore required to generate relaxant activity following reaction with nitric oxide.5. Reacting L-cysteine (10 mM) with nitric oxide (~ 3 mM) under more stringent oxygen-free conditions followed by purging to remove free nitric oxide resulted in the generation of low relaxant activity and small absorption peaks at 218 and 335 nm and these were unaffected upon exposure to the air. In contrast, admitting air to the reaction chamber before purging enhanced both relaxant activity and the absorption peaks at 218 and 335 nm by some 40 fold and the solution turned pink due to the appearance of another absorption peak at 543 nm. This enhanced relaxant activity was not due to nitrogen dioxide being the reactive species, since at 0.1 mM this gas failed to react with L-cysteine to generate relaxant activity, and at 1 mM generated less activity than the equivalent concentration of nitricoxide.6. The relaxant activity generated by reacting nitric oxide with L-cysteine or L-glutathione was abolished following treatment with haemoglobin (3 MicroM), methylene blue (10 MicroM) or Nmethylhydroxylamine(100 MicroM), but was unaffected by N0-nitro-L-arginine (30 MicroM). Furthermore, two agents that generate superoxide anion, pyrogallol (0.1 mM) and hydroquinone (0.1 mM), also inhibited this relaxant activity as well as that induced by authentic nitric oxide (0.3 MicroM) but as previously reported, had no effect on relaxation induced by NANC nerve stimulation. Superoxide dismutase(100 u ml1) reversed the actions of pyrogallol and hydroquinone but had no effect on NANC relaxation.7. In conclusion, the reaction of nitric oxide with L-cysteine or L-glutathione generates relaxant activity which exceeds that of nitric oxide alone and probably results from formation of S-nitrosocysteine and S-nitrosoglutathione, respectively. The effects of pyrogallol and hydroquinone suggest that the NANCneurotransmitter is a superoxide anion-resistant, nitric oxide-releasing molecule and that neither S-nitrocysteine nor S-nitrosoglutathione is a suitable candidate for this.
Animals↗
Beneficial effects of buspirone therapy in Huntington's disease.
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Aggression↗
Effects of vertebral axial decompression on intradiscal pressure.
The object of this study was to examine the effect of vertebral axial decompression on pressure in the nucleus pulposus of lumbar discs. Intradiscal pressure measurement was performed by connecting a cannula inserted into the patient's L4-5 disc space to a pressure transducer. The patient was placed in a prone position on a VAX-D therapeutic table and the tensionometer on the table was attached via a pelvic harness. Changes in intradiscal pressure were recorded at resting state and while controlled tension was applied by the equipment to the pelvic harness. Intradiscal pressure demonstrated an inverse relationship to the tension applied. Tension in the upper range was observed to decompress the nucleus pulposus significantly, to below -100 mm Hg.
Adult↗