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Metabolism and pharmacokinetics of 1-(2'-trimethylacetoxyethyl]-2-ethyl-3-hydroxypyridin-4-one (CP117) were studied in the rat. Urinary recovery studies were conducted in normal (oral and intravenous) and iron-overloaded rats (500 mg Fe/kg body weight; oral only). In normal rats, the majority of the dose recovered in the urine was as the hydrophilic metabolite, CP102, accounting for 69.7 +/- 9.4% (oral) and 80.7 +/- 7.9% (intravenous) of the administered dose. There was, however, a dramatic decrease in the amount of CP102 recovered (47.7 +/- 5.9%) (p < or = 0.05) in the iron-loaded group of animals. The amount of CP102 glucuronide conjugate recovered in the normal and iron-overloaded rats after oral administration of CP117 did not differ significantly with values of 6.5 +/- 2.5% and 7.1 +/- 2.5%, respectively. There was, however, a significant increase in CP102 glucuronide conjugate (13.7 +/- 3.0%) (p < or = 0.05) after intravenous administration of CP117. Urinary iron content was determined in the iron-overloaded and normal (oral) animals. Negligible levels of the CP117 iron complex and only 0.6 +/- 0.2% was present as the corresponding CP102 complex in the urine of normal animals. Less than 0.1% of the administered dose was recovered as CP117-iron complex and only 1.3 +/- 0.2% as CP102-iron complex in the iron-overloaded animals. Total recovery of the administered dose was significantly different between normal (po) and iron-overloaded groups of animals, decreasing from 76.4 +/- 11.7% to 57.2 +/- 9.6%, respectively (p < or = 0.05). There was no significant difference between the two routes of administration in normal animals, with total recovery of the administered dose of CP117 being 96.1 +/- 9.1% by the intravenous route. Intravenous and oral pharmacokinetics of CP117 was studied in the rat at a fixed dose of 450 mumol/kg. The AUC of the drug was 43.2 +/- 9.1 mumol/liter . hr and 4.1 +/- 1.8 mumol/liter.hr via the intravenous and oral routes, respectively, thus indicating that the systemic bioavailability of the drug is < 10%. Pharmacokinetic parameters of the drug determined by the intravenous route indicate that CP117 has a plasma clearance of 10.9 +/- 3.0 mumol/liter.hr, a mean residence time of 0.14 +/- 0.05 hr, and volume of distribution at steady-state of 1.54 +/- 0.52 liters.kg-1. The Cmax and tmax of CP117 were 12.1 +/- 2.5 mumol/liter and 7.0 +/- 2.7 min, respectively. The AUC of the main metabolite, CP102, decreased from 425.3 +/- 8.5 mumol/liter.hr to 282 +/- 31 mumol/liter.hr via the intravenous and oral routes, which is presumed to reflect differences in hepatic extraction and routes of elimination of the drug. Parallel absorption studies conducted using the in situ isolated rat gut loop model indicate that the majority of the administered dose was absorbed intact as the parent drug with mesenteric vein AUC values of 3.1 +/- 1.7 mmol/liter.hr and 0.3 +/- 0.04 mmol/liter.hr for CP117 and CP102, respectively.

1. The mechanism of action of sumatriptan on coronary flow was examined before and after two different forms of endothelial ablation in guinea-pig isolated hearts. The mechanism was assessed in terms of the influence of the integrity of the coronary endothelium, the role of release of nitric oxide (NO) from the endothelium, and the receptor subtypes mediating the effects. 2. Continuous perfusion with sumatriptan reduced coronary flow, but the concentration-response curve was v-shaped. Sumatriptan (0.001-0.1 microM) caused a concentration-dependent decrease in coronary flow with the maximum effect achieved at 0.23 +/- 0.04 microM. The pEC50 was 8.49 +/- 0.07. At higher concentrations (0.1-10 microM) there was a concentration-dependent diminution of the vasoconstrictor effect. Endothelial ablation by saponin removed the diminution in the vasoconstrictor effect. In contrast pretreatment with NG-nitro L-arginine methyl ester (L-NAME) (100 microM. 45 min perfusion) did not affect it. This was despite both saponin and L-NAME being effective in reducing basal release of NO into the coronary effluent (measured by chemiluminescence) to the same extent (71 +/- 3 and 73 +/- 2%, respectively). 3. GR127935, a selective 5-hydroxytryptamine1D (5-HT1D) receptor antagonist (3 and 10 nM), which by itself had no effect on coronary flow or NO release, antagonized the vasoconstrictor response to sumatriptan and unmasked a sumatriptan-induced concentration-dependent increase in coronary flow and NO release. These increases in coronary flow and NO release were abolished by pretreatment with either saponin or L-NAME. 4. Mesulergine, a 5-HT2 receptor antagonist which had no effect by itself on basal coronary flow or NO release, inhibited the vasodilator response to sumatriptan that occurred in the presence of GR127935, and actually enhanced the vasoconstrictor response, increasing the max mum fall in coronary flow from -3.9 +/- 0.4 to -5.2 +/- 0.4 ml min-1 g-1 (P < 0.05). The diminution of vasoconstrictor effect of sumatriptan was abolished by mesulergine and by pretreatment with saponin, but not by L-NAME. 5. In conclusion, guinea-pig coronary arteries constrict to low concentrations of sumatriptan, causing a reduction in coronary flow. This effect appears to be caused by 5-HT1D agonism with the receptors located on the coronary vascular smooth muscle. With higher concentrations of sumatriptan this is partially offset by a weaker vasodilator effect, which is caused by low affinity 5-HT2 agonism. Although this effect is endothelium-dependent. It is not caused by the release of NO. Interestingly, when the vasoconstrictor effect of sumatriptan was inhibited by the 5-HT1D antagonist GR127935, a high affinity vasodilator effect of sumatriptan was unmasked. This is 5-HT2 receptor mediated and is caused by release of NO from the coronary endothelium. 6. In man, sumatriptan, and 5-HT may both be capable of causing pathogenic coronary vasoconstriction. The implications of the present data are that the scope for this may depend greatly on (i) the extent of underlying endothelial dysfunction, (ii) the extent of endothelial 5-HT2 receptor-mediated release of vasodilator autacoids (which include NO) and (iii) the extent of smooth muscle 5-HT1D receptor-mediated vasoconstriction.

As part of the 1990/1991 Pakistan Demographic and Health Survey, data were collected on the outcome of 26,408 births to 6,611 women, with mortality rates investigated at specific age intervals during the first 5 years of life. Bivariate and multivariate logistic regression analyses were employed to examine the comparative roles of consanguineous marriage and a number of demographic and socioeconomic factors, including the sex of the child, maternal age, maternal education, birth interval and birth order, as determinants of early death. The results indicate that, even after controlling for these non-genetic variables, inbreeding at the level of first cousin exerted a significant adverse effect on survival in four of the five age intervals examined, neonatal, post-neonatal, infant and under 5 years.

We have previously reported that 1-(2-trifluoromethylphenyl) imidazole (TRIM) is a potent inhibitor of mouse cerebellar neuronal NOS (nNOS) in vitro with very much reduced activity against bovine aortic endothelial NOS (eNOS). Using purified rat brain nNOS as enzyme source we have now probed the mechanism of action of TRIM. nNOS activity was linear over the first 5 min incubation. Optimal enzyme activity occurred in the presence of NADPH (0.5 mM), calcium chloride (75 microM), tetrahydrobiopterin (12 microM) and calmodulin (10 microg/ml) as cofactors. TRIM was a poor inhibitor of nNOS (IC50, 462.0 microM) compared with L-N(G) nitro arginine (L-NOARG, IC50, 0.32 microM). Removal of tetrahydrobiopterin (but not calmodulin) from the incubation medium greatly enhanced the nNOS inhibitory activity of TRIM (IC50, 32.0 microM) but not L-NOARG (IC50, 0.34 microM). In the absence of added tetrahydrobiopterin, TRIM competed with L-arginine for the substrate binding site on the nNOS enzyme with a Ki value of 47.3 microM. The present experiments suggest that TRIM interferes with the binding of both L-arginine and tetrahydrobiopterin to their respective sites on the nNOS enzyme.

Idiopathic Parkinson's disease (PD) involves a documentable decline in the activity of mitochondrial complex I in substantia nigra (1-3). We have EPR spectroscopy to investigate complex I in human substantia nigra and globus pallidus. EPR signals characteristic of the iron-sulfur centers of complexes I and II were observed with globus pallidus, with no significant difference between control and PD. These complex 1 signals could not be clearly observed in substantia nigra. Instead, nitric oxide (NO.) radicals in PD nigra were detected at g approximately 2.08, 1.98 due to [haem-NO] formation. Although an EPR signal indicative of haem-NO was observed with control nigra, it lacked the distinctive g approximately 1.98 trough observed with PD nigra. As PD is associated with a reactive gliosis, the difference in the haem-NO EPR signal, between control and PD nigra, may result from cytotoxic NO. generated by microglia in PD substantia nigra.

Ascorbic acid has a multiplicity of antioxidant properties, but it can exert pro-oxidant effects in vitro, usually by interaction with transition metal ions. It is as yet uncertain that these pro-oxidant effects have any biological relevance: some of the available data are summarized.

Nitric oxide (NO) protects the heart against some forms of reperfusion-associated dysfunction (e.g. arrhythmias). Its role in protecting against other types of dysfunction is controversial. NO ameliorates polymorphonuclear cell-induced exacerbation of stunning. Here, whether endogenous NO protects against contractile dysfunction in a polymorphonuclear cell-free model has been tested. Isolated rat hearts (n = 6 per group) were perfused with Krebs solution for 15 min. They were then perfused with test solution: Krebs, or Krebs containing 100 microM NG-nitro-L-arginine methyl ester (L-NAME) (a concentration shown previously to significantly reduce NO content in coronary effluent), 100 microM L-NAME plus 10 mM L-arginine (the latter shown previously to be sufficient to surmount the effect of L-NAME), or 10 mM L-arginine alone. After 10 min of this, the hearts were subjected to 60-min normothermic global ischemia followed by reperfusion with the same test solution as before. A time-matched (sham) group was perfused continuously with Krebs. L-NAME hastened the onset of ischemic contracture (P < 0.05) and increased its peak value from 67.8 +/- 4.6 mmHg to 93.0 +/- 4.9 mmHg (P < 0.05). Both effects were prevented by co-perfusion with 10 mM L-arginine. Initially, reperfusion exacerbated diastolic contracture, but diastolic pressure at a constant ventricular volume fell from 112 +/- 27 mmHg to 73 +/- 19 mmHg between the 5th and 60th min of reperfusion in drug-free hearts, indicative of recovery from diastolic stunning. This recovery was not exacerbated or lessened by perfusion with L-NAME or L-arginine. Left ventricular developed pressure increased from 42 +/- 2 mmHg to 106 +/- 18 mmHg in controls between 5 and 30 min after the start of reperfusion, the latter value being indistinguishable from that in the sham group. At this time, the value in the L-NAME group was similar (78 +/- 18 mmHg). This indicated complete recovery from systolic stunning in both groups 30 min after the start of reperfusion. However, earlier after the start of reperfusion, there had been zero pressure development in the L-NAME group (P < 0.05 v the control group). This was associated with severe impairment of recovery of coronary flow, e.g. of only 18% of the mean coronary flow in controls 5 min after the start of reperfusion (P < 0.05). At 30 min after the start of reperfusion (when systolic function had recovered in the L-NAME group), flow recovery had increased in this group to 96% of the mean control values. The impairment in rates of recovery of systolic function and coronary flow in the L-NAME group were each prevented by coperfusion with L-arginine (P < 0.05). In conclusion, endogenous NO may delay the onset and reduce the magnitude of ischemic contracture but despite this, appears not to facilitate early recovery from systolic and diastolic stunning as a result of any direct action in the myocardium. The beneficial effect it does possess in this polymorphonuclear cell-free preparation is transient and results from mediation of rapid recovery of coronary flow during reperfusion.

A range of substituted isothiourea compounds including S-isopropylisothiourea (IPTU), S-methylisothiourea (SMT), S-ethylisothiourea (ETU), N-pentylisothiourea (PTU), S-(2 aminoethyl)isothiourea (AETU), and S-acetamidoisothiourea (AATU) inhibit mouse spinal cord/cerebellar neuronal nitric oxide synthase (nNOS) and bovine aortic endothelial cell eNOS in vitro. IP administration of isothioureas increased mean arterial blood pressure of the urethane-anaesthetised mouse (rank order of effect: IPTU > ETU > SMT > AETU). PTU and AATU were without vasopressor activity. IPTU (50 mg/kg, IP) inhibited late phase formalin-induced hindpaw licking behaviour in the mouse while SMT (50 mg/kg, IP) was without effect. Neither compound influenced the formalin-induced increase in hindpaw weight reflecting a lack of significant peripheral antioedema effect in this model. IPTU (50 mg/kg, IP) but not SMT (50 mg/kg, IP) inhibited mouse spinal cord and cerebellar NOS activity measured ex vivo in animals killed 45 min after injection. The present study confirms the potent NOS inhibitory effect of selected substituted isothioureas in vitro. Little or no isoform selectivity (i.e., nNOS vs. eNOS) was apparent. The potent vasopressor effect of isothioureas indicates that these compounds may be of limited use as tools to study the role of nitric oxide in pain perception.

The [2Fe-2S] ferredoxin from Clostridium pasteurianum contains five cysteine residues in positions 11, 14, 24, 56, and 60. This pattern is unique, and a combination of site-directed mutagenesis and spectroscopy is therefore being implemented to identify the ligands of the [2Fe-2S] cluster. The possible involvement of ligands other than cysteine in some molecular variants of this ferredoxin has been considered, histidines being likely candidates. Therefore, the three histidine residues in positions 6, 7, and 90 of the amino acid sequence have been individually and collectively replaced by alanine or valine. The mutated ferredoxins have been purified and were all found to contain [2Fe-2S] clusters of which the UV-visible absorption spectra were identical to that of the wild-type protein. The H6A/H7A/ H90A triply mutated ferredoxin was further characterized by EPR and by ESEEM spectroscopy and was found to differ only marginally from the wild-type protein. The ESEEM spectra of wild-type ferredoxin displayed weak 14N hyperfine interactions at the three principal g-factors of the [2Fe-2S] center. The estimated 14N coupling constants (Aiso = 0.6 MHz; e2qQ approximately 3.3 MHz) indicate that the ESEEM effect is most likely due to 14N from the polypeptide backbone. 2H2O ESEEM spectra showed that the [2Fe-2S] cluster is accessible for exchange with solvent deuterons. ESEEM spectra of the previously characterized C24A and C14A/C24A variants have been recorded and were also found to be very similar to those of the wild-type protein. There was no evidence for coordination of the [2Fe-2S] cluster by [14N]histidine or other 14N nuclei, in either wild-type or mutant forms of the ferredoxin. By these criteria, the environment of the [2Fe-2S] center is not distinguishable from those in plant-type ferredoxins. Non-cysteinyl coordination most probably occurs only in the C14A/C24A variant, which contains no more than three cysteine residues. The data shown here indicate that the fourth ligand of the [2Fe-2S] cluster is neither a histidine residue nor another nitrogenous ligand. The possibility of oxygenic coordination for this molecular variant is discussed.

Nitric oxide (NO) is an endogenous protectant against reperfusion-induced ventricular fibrillation (VF) in the rat isolated heart. Here, the following were investigated: (1) the tissue source of cardioprotective NO using a novel inhibitor (7-nitro indazole; 7-NI) of the neuronal form of NO synthase (NOS) and direct detection of coronary effluent NO by chemiluminescence; and (2) the species dependence by comparing rat and rabbit hearts. Perfusion with modified Krebs solution was followed by 60 min left regional ischemia and 10 min reperfusion. 7-NI (1 microM) increased the incidence of VF from 0% to 60% in rat hearts (n = 10; P < 0.05). Co-perfusion with L-arginine (1 mM) reduced VF incidence to 20% (P:N.S. v controls). The inactive analog of 7-NI (6-amino indazole: 6-AI) had no pro-fibrillatory activity. Neither 7-NI nor 6-AI affected coronary flow or recovery of flow during reperfusion. 7-NI reduced basal coronary effluent NO levels to below the limit of detection (< 1 pmol), but a massive increase in NO levels occurred when L-arginine was co-perfused with 7-NI. Although 7-NI had no effect on basal coronary flow and, by implication, resting NO release, it was found, in separate studies, to antagonise substance P-induced vasodilatation and NO release, suggesting that its neuronal selectivity is lost in the presence of an exogenously administered activator of endothelial NOS in rat hearts. In rabbit hearts, in contrast, 7-NI had no effect on VF or NO levels. However, in rabbit hearts the isozyme non-selective NO synthase blocker, NG-nitro-L-arginine methyl ester (L-NAME; 100 microM), increased VF incidence from 0 to 50% (P < 0.05) and, during the first minute of reperfusion, reduced NO levels from 4929 +/- 893 to 2505 +/- 483 pmol/min/g (P < 0.05) and recovery of coronary flow by 22% (P < 0.05). Each of these effects were prevented by L-arginine co-perfusion. These data indicate a role for basally released NO as an endogenous antifibrillatory cardioprotectant in rat and rabbit isolated heart and indicate that the tissue source (neuronal in rat but not in rabbit heart) is species-dependent.

1. We assessed whether a submaximal concentration (1 microM) of 5-hydroxytryptamine (5-HT) releases nitric oxide (NO) from the coronary endothelium in guinea-pig perfused heart (n = 5 or 6/group) by direct detection of NO in coronary effluent, and determined whether this accounts for the associated coronary dilation. We also tested whether saponin is a selective and specific tool for examining the role of this mechanism in mediating agonist-induced coronary dilatation. 2. Continuous 5 min perfusion with 5-HT, or acetylcholine (ACh; 1 microM), substance P (1 nM) or sodium nitroprusside (SNP; 1 microM) increased coronary flow from baseline by 3.6 +/- 0.2, 3.4 +/- 0.2, 1.8 +/- 0.1 and 4.1 +/- 0.2 ml min-1 g-1, respectively (all P < 0.05). Coronary effluent NO content, detected by chemiluminescence, was correspondingly increased from baseline by 715 +/- 85, 920 +/- 136, 1019 +/- 58 and 2333 +/- 114 pmol min-1 g-1, respectively (all P < 0.05). 3. Continuous perfusion for 30 min with NG-nitro-L-arginine methyl ester (L-NAME) 100 microM reduced basal coronary effluent NO content by 370 +/- 32 pmol min-1 g-1 and coronary flow by 7.5 +/- 0.5 ml min-1 g-1 (both P < 0.05). Saponin (three cycles of 2 min of 30 micrograms ml-1 saponin perfusion interrupted by 2 min control perfusion) reduced basal coronary NO content by a similar amount (307 +/- 22 pmol min-1 g-1) but reduced basal coronary flow by only 0.6 +/- 0.2 ml min-1 g-1 (P < 0.05 versus the effect of L-NAME). 4. The increases in coronary flow in response to (5-HT), ACh and substance P were reduced (all P < 0.05) by 100 microM L-NAME to 1.2 +/- 0.3, 1.2 +/- 0.4 and 0.3 +/- 0.3 ml min-1 g-1, respectively. However, the flow increase in response to SNP was not reduced; it was in fact increased slightly to 4.8 +/- 0.4 ml min-1 g-1 (P < 0.05). 5. Similarly, after treatment with saponin, the increases in coronary flow in response to 5-HT, ACh and substance P were reduced to 2.1 +/- 0.3, 1.3 +/- 0.3 and 0.4 +/- 0.2 ml min-1 g-1, respectively (all P < 0.05). Again, the response to SNP was increased slightly to 4.6 +/- 0.5 ml min-1 g-1 (P < 0.05). 6. L-NAME and saponin also inhibited 5-HT, ACh and substance P-induced NO release (P < 0.05), without affecting equivalent responses to SNP. 7. For substance P, the change in coronary flow (delta CF) correlated with log10 delta NO in the presence and absence of saponin and L-NAME; delta CF = 1.2(log delta NO) 1.9; r = 0.92; P < 0.05. For 5-HT the relationship was delta CF = 2.2(log delta NO-2.7; r = 0.79; P < 0.05, indicating that 5-HT causes a disproportionately greater increase in coronary flow per release of NO. This was taken to indicate that 5-HT relaxes coronary vasculature in part by releasing NO, but in part by additional mechanisms. ACh resembled 5-HT in this respect. 8. Saponin had no effect on cardiac systolic or diastolic contractile function assessed by the construction of Starling curves with an isochoric intraventricular balloon. 9. In conclusion, despite its minimal effect on basal coronary flow, saponin is an effective tool for revealing endothelium-dependent actions of coronary vasodilator substances and has selectivity in that it does not impair endothelium-independent vasodilatation or cardiac contractile function. 5-HT dilates guinea-pig coronary arteries largely by the release of NO from the coronary endothelium.

1. The ability of a range of substituted imidazole compounds to inhibit mouse cerebellar neuronal nitric oxide synthase (nNOS), bovine aortic endothelial NOS (eNOS) and inducible NOS (iNOS) from lungs of endotoxin-pretreated rats was investigated. In each case the substrate (L-arginine) concentration employed was 120 nM. 2. 1-(2-Trifluoromethylphenyl) imidazole (TRIM) was a relatively potent inhibitor of nNOS and iNOS (IC50S of 28.2 microM and 27.0 microM respectively) but was a relatively weak inhibitor of eNOS (IC50, 1057.5 microM). The parent compound, imidazole, was a weak inhibitor of all three NOS isoforms (IC50S: nNOS, 290.6 microM; eNOS, 101.3 microM; iNOS, 616.0 microM). Substitution of imidazole with a phenyl group to yield I-phenylimidazole (PI) resulted in an isoform non-selective increase in inhibitory potency (IC50S: nNOS, 72.1 microM; eNOS, 86.9 microM; iNOS, 53.9 microM). Further substitution of the attached phenyl group resulted in an increase in nNOS and a decrease in eNOS inhibitory potency as in TRIM, 1-chlorophenylimidazole (CPI; IC50S: nNOS, 43.4 microM; eNOS, 392.3 microM; iNOS, 786.5 microM) and 1-(2,3,5,6-tetrafluorophenyl) imidazole (TETRA-FPI; IC50S; nNOS, 56.3 microM; eNOS, 559.6 microM; iNOS, 202.4 microM). 3. The ability of TRIM to inhibit mouse cerebellar nNOS activity in vitro was influenced by the concentration of L-arginine (0.12-10.0 microM) in the incubation medium. When mouse cerebellar nNOS was used as enzyme source a double reciprocal (Lineweaver-Burk) plot in the presence/absence of TRIM (50 microM) revealed a competitive inhibitory profile. The K(m) for L-arginine and the Ki for TRIM calculated from these data were 2.4 microM and 21.7 microM, respectively. The ability of TRIM to inhibit mouse cerebellar nNOS activity in vitro was unaffected by varying the time of exposure of the enzyme to TRIM from 0-60 min at 0 degree C. 4. TRIM exhibits potent antinociceptive activity in the mouse as evidenced by inhibition of acetic acid induced abdominal constrictions. The ED50 for TRIM following i.p. administration was 20 mg kg-1 (94.5 mumol kg-1). The antinociceptive effect of TRIM was reversed by pretreatment of animals with L-arginine (50 mg kg-1, i.p.) and was not accompanied by sedation, motor ataxia or behavioural changes (rearing, crossing, circling, dipping) as assessed by use of a box maze procedure. 5. L-NG nitro arginine methyl ester (L-NAME, 20 mg kg-1, i.v.) but not TRIM (0.5-20 mg kg-1, i.v.) increased mean arterial blood pressure (MAP) in the urethane-anaesthetized rat. 6. L-NAME (100 microM) potentiated the contractile response of the rabbit isolated aorta to phenylephrine (ED50; 0.084 +/- 0.01 microM in the presence and 0.25 +/- 0.05 microM in the absence of L-NAME; maximum response, 7.7 +/- 0.4 g in the presence and 5.6 +/- 0.5 g in the absence of L-NAME, n = 6, (P < 0.05) whilst TRIM (1-100 microM) was without effect. L-NAME (100 microM) but not TRIM (1-100 microM) also reduced carbachol-induced relaxation of the phenylephrine-precontracted rabbit aorta preparation. 7. L-NAME (50 microM) potentiated the vasoconstrictor effect of bolus-injected noradrenaline (10-1000 nmol) and reduced the vasodilator effect of carbachol (10 microM) added to the Krebs reservoir in the rat perfused mesentery preparation. L-NAME (50 microM) also reduced nitric oxide (NO) release (measured by chemiluminescence of nitrite in the Krebs perfusate) in response to noradrenaline (100 nmol; 53.8 +/- 4.0 pmol ml-1 in the presence and 84.8 +/- 8.0 pmol ml-1 in the absence of L-NAME, n = 15, P < 0.05) and carbachol (10 microM; 63.9 +/- 5.0 pmol ml-1 in the presence and 154.0 +/- 9.0 pmol ml-1 in the absence of L-NAME, n = 15, P < 0.05). TRIM (50 microM) did not affect either the vasoconstrictor response to noradrenaline or the vasodilator response to carbachol or the accompanying release of NO from the perfused rat mesentery.

Factor VII coagulant activity (FVIIc) is associated with an increased risk of fatal ischaemic heart disease (IHD). Several reports have suggested that dietary fat intake or hypertriglyceridaemia are associated with elevated levels of FVII. This study demonstrates that an intake of long-chain fatty acids sufficient to induce postprandial lipaemia in healthy subjects leads to a substantial elevation in both FVIIc and the concentration of FVII circulating in the activated form. Such an increase in FVIIc could not be induced by medium-chain triglycerides. These results suggest that the consumption of a sufficient amount of long-chain triglycerides to induce postprandial lipaemia induces the activation of FVII.

The purpose of this study was to examine the use of ancillary personnel to augment nursing staff, a recurring theme in the history of nursing. The focus was the use of untrained nursing personnel in Great Britain during the years 1914-1918. The findings demonstrate both the nature and extent of dilution within nursing and its effects in terms of social relationships and occupational structure.

RISK FACTORS IN THE HEALING OF VENOUS ULCERS THE ACTIVATION AND EFFECTS OF NEUTROPHILS AND MONOCYTES COMPRESSION STOCKINGS AND LEG ULCER RECURRENCE PRESSURE SORE PREVENTION AND TREATMENT.

This paper explores differences and similarities between participants who had selected nursing as an occupational choice from childhood and those for whom nursing was not a childhood occupational choice. The implications of the findings are discussed.

Objective: To determine whether or not aspirin further potentiates the greater post-prandial thermogenesis induced by ephedrine with caffeine., Design: Determination of the acute metabolic rate response to the following treatments: 1050 kJ liquid meal (M); meal plus ephedrine (30 mg) and caffeine (100 mg) (MEC) or meal plus ephedrine, caffeine and aspirin (300 mg) (MECA)., Subjects: Lean, pre-disposed obese and obese women (n = 10 each group)., Measurements: Pre- and post-treatment metabolic rate determinations via indirect calorimetry. Post-treatment measurements made at 20 min intervals for a total of 160 min., Results: In all groups, metabolic rate increased significantly more following the MEC or MECA, compared to the meal only (p < 0.05). The obese group had a significantly greater absolute increase in metabolic rate following the MECA and MEC compared to both the lean and pre-disposed obese groups (p < 0.05). Metabolic rate remained elevated at the end of the 160 min following all treatments., Conclusion: Aspirin does not further potentiate the acute thermic effect of ephedrine and caffeine with a meal. However, the full thermogenic response was not measured and longer duration studies are necessary to confirm these results.

Free radicals and antioxidants are widely discussed in the clinical and nutritional literature. Antioxidants are needed to prevent the formation and oppose the actions of reactive oxygen and nitrogen species, which are generated in vivo and cause damage to DNA, lipids, proteins, and other biomolecules. Endogenous antioxidant defenses (superoxide dismutases, H2O2-removing enzymes, metal binding proteins) are inadequate to prevent damage completely, so diet-derived antioxidants are important in maintaining health. Many dietary compounds have been suggested to be important antioxidants: The evidence for a key role of vitamins E and C is strong, but that for carotenoids and related plant pigments is weaker. Interest is also growing in the role of plant phenolics, especially flavonoids. Some antioxidants can exert prooxidant effects in vitro, but their physiological relevance is uncertain. Experimental approaches to the optimization of antioxidant nutrient intake are proposed.

The thymus is a very complex organ that regulates T-cell production Thymocytes (immature T-cells) constitute by far the largest cellular population in the organ (several billions of thymocytes in a child's thymus), but small numbers of other hematopoietic cells are found in the intrathymic microenvironment, such as thymic monocytes, macrophages, interdigitating dendritic cells, and B-cells Stromal cells of nonhematopoietic origm comprise thymic epithelial cells (TEC) organized in a network throughout the organ, thymic fibioblasts of the capsule and interlobular septae, and endothelial cells of the thymic vasculature The proportion of these thymic cellular components varies with age (1). Fat infiltration becomes significant at puberty and increases throughout adulthood. Intrathymic T-cell maturation is supported in part by TEC, which express cell-surface molecules interacting with counterreceptors on the maturing thymocytes (2-4) Importantly, TEC induce positive selection and major histocompatibility complex restriction of T-cells (5) In vitro studies have shown that TEC produce numerous cytokines (4, 6, 7), which may directly and/or indirectly contribute to T-cell maturation. Reciprocally, TEC functions are affected by interactions with T-cells (t4, 8). Monolayer cultures of TEC provide in vitro systems to study the biology of TEC (2-7) However, investigators should be aware that monolayer cultures may not be representative of a three-dimensionally structured TEC network, and the function of isolated cells may differ from that of cells in the midst of a complex environment One method to obtain highly purified monolayer cultures of human TEC is described here Nontransformed human TEC can be propagated and passaged up to six times before cells become senescent. Careful "budgeting" of the cell stocks by freezing early passages can provide a long-lasting supply of purified TEC strains with determined purity.

One- and two-dimensional (1D and 2D) electron spin-echo envelope modulation (ESEEM) spectroscopy has been used to investigate the ligand environment of the [2Fe-2S] cluster from the terminal dioxygenase (ISPBED) of the Pseudomonas putida benzene dioxygenase complex. The modulation frequencies observed in the 0.5-8.5 MHz region of the Fourier transforms of 1D and 2D ESEEM spectra measured across the electron paramagnetic resonance (EPR) absorbance envelope (from gz through to gx) are consistent with their assignment to two 14N nuclei. Using hyperfine sublevel correlation spectroscopy (HYSCORE), two sets of correlated double quantum transitions sharing the same hyperfine coupling were observed and were identified as being due to the same two 14N nuclei. On the basis of the isotropic hyperfine and quadrupolar couplings estimated for these 14N nuclei [N(1), Aiso = 3.6 MHz and e2qQ = 2.2-2.8 MHz; N(2), Aiso = 4.8 MHz and e2qQ = 2.2-2.4 MHz], the ESEEM pattern of ISPBED is assigned to two histidine nitrogens which are directly coordinated to the reduced iron-sulfur cluster. Bonding parameters of the two [14N]histidine ligands were calculated from these hyperfine couplings. The primary covalent contributions to the hyperfine interaction arise from 14N-to-Fe2+ sigma bonds. For N(1), our analysis of the percentage of unpaired 2s and 2p electrons gave f2s approximately 1.3% and f2p approximately 0.2%, while values of f2s approximately 1.7% and f2p approximately 1.4% were estimated for N(2). Comparison of these values with those determined from electron nuclear double resonance (ENDOR) data of the Rieske-type [2Fe-2S] center of Pseudomonas cepacia phthalate dioxygenase [Gurbiel, R. J., Batie, C. J., Sivaraja, M., True, A. E., Fee, J. A., Hoffman, B. M., & Ballou, D. P. (1989) Biochemistry 28, 4861-4871] indicates an apparent reduction in unpaired electron spin density residing on the two 14N ligands of ISPBED. Analysis of slices of the HYSCORE spectrum has provided evidence for another 14N nucleus (A approximately 1.1 MHz, e2qQ = 3.3 MHz), which we have attributed to a weakly coupled peptide nitrogen, similar to those observed for ferredoxin-type [2Fe-2S] clusters. This type of weak interaction has not been previously described by the detailed ENDOR and ESEEM studies of Rieske-type centers. The resolution of the spectra demonstrates the effectiveness of 2D ESEEM for the disentanglement of multiple hyperfine interactions to metalloprotein centers.

The effect of a novel leuktriene B4 receptor antagonist N-[5[[8-(1-hydroxy-2- phenyl)ethyl]dibenzofuran-2yl]5-hydroxypentanoyl]pyrrolidine (PF 10042) has been evaluated in comparison with 2-[3(1-hydroxyhexyl)phenoxymethyl]quinoline hydrochloride (PF 5901), a specific inhibitor of the 5-lipoxygenase pathway of arachidonic acid metabolism, against platelet activating factor (PAF) and allergen induced bronchial hyperresponsiveness and pulmonary eosinophil infiltration in the guinea pig. PF 10042 significantly displaced radiolabelled [3H]leukotriene B4 from binding sites on human neutrophils with an EC50 of 3 muM. PF 10042 (100 mg/kg, i.p.) significantly inhibited PAF and allergen induced bronchial hyperresponsiveness without reducing the concomitant eosinophil infiltration, whereas PF 5901 (100 mg/kg, p.o.) significantly inhibited both PAF and allergen induced bronchial hyperresponsiveness and eosinophil infiltration. We suggest from these results that PAF and allergen induced bronchial hyperresponsiveness may be secondary to the release of leukotriene B4, but this lipoxygenase metabolite does not contribute significantly to the observed eosinophil infiltration.

1. After a period of myocardial ischaemia, reperfusion of the myocardium can elicit cardiac arrhythmias. Susceptibility to these arrhythmias declines with time, such that a preceding period of more than approximately 40 min ischaemia is associated with few reperfusion-induced arrhythmias. We have tested the hypothesis that this decline in susceptibility occurs, in part, because of protection by endogenous guanosine 3':5'-cyclic monophosphate (cyclic GMP). 2. Rat isolated hearts were subjected to 60 min left regional ischaemia followed by reperfusion (n = 10 per group). Methylene blue (20 microM), a soluble guanylate cyclase inhibitor, raised the incidence of reperfusion-induced ventricular fibrillation (VF) from 10% in control hearts to 80% (P < 0.05). This effect of methylene blue was abolished by co-perfusion with zaprinast (100 microM), a phosphodiesterase inhibitor which, in the rat heart, is cyclic GMP-specific (specific for the type-V phosphodiesterase isozyme). 3. Methylene blue reduced cyclic GMP levels in the ischaemic, non-ischaemic and reperfused myocardium (P < 0.05) to 50 +/- 10, 52 +/- 12 and 70 +/- 7 fmol mg-1 tissue wet weight, respectively from control values of 143 +/- 38, 147 +/- 43 and 156 +/- 15 fmol mg-1. Co-perfusion with zaprinast prevented this effect, and cyclic GMP levels were actually elevated (P < 0.05) to 366 +/- 102, 396 +/- 130 and 293 +/- 22 fmol mg-1 in ischaemic, non-ischaemic and reperfused myocardium, respectively. Zaprinast by itself also elevated cyclic GMP content. Cyclic AMP levels were not affected by zaprinast or methylene blue. 4. In conclusion, when endogenous cardiac cyclic GMP synthesis is reduced, susceptibility to reperfusion-induced VF after sustained ischaemia is substantially increased. The effect is prevented by inhibiting cyclic GMP degradation. Therefore cyclic GMP appears to be an endogenous intracellular cardioprotectant, and its actions may account for the low susceptibility to VF normally encountered in hearts reperfused after sustained ischaemia.

Reliability of the Waterlow Score Classic Research: MOIST WOUND HEALING.

1-(2-trifluoromethylphenyl)imidazole (TRIM) is a potent inhibitor of neuronal (mouse cerebellar) and inducible (lung from endotoxin-pretreated rats) isoforms of nitric oxide synthase (NOS) with IC50 values of 28.2 microM and 27.0 microM, respectively. In contrast, TRIM is a poor inhibitor of bovine aortic endothelial NOS with an IC50 of 1057.5 microM. TRIM (10-50 mg kg-1) administered i.p. exhibits dose-related antinociceptive activity in the mouse (assessed as inhibition of late phase formalin-induced hindpaw licking behaviour) with an ED50 of 85.8 mumol kg-1. In contrast, TRIM (50 mg kg-1, i.p.) failed to influence mean arterial blood pressure in the urethane-anaesthetized mouse. Thus, TRIM may be of use as an experimental tool with which to investigate the biological roles of nitric oxide (NO) within the central nervous system.

Objectives: Evidence suggests that histamine may function as one of many endogenous biochemical mediators of ischaemia- and reperfusion-induced ventricular fibrillation (VF). The H2 receptor subtype has been hypothesised to mediate this action. Our objective was to test this hypothesis., Methods: The hypothesis predicts that H2 antagonists should prevent VF. We tested this by evoking ischaemia- and reperfusion-induced VF using the isolated perfused rat heart (Langendorff preparation) and performing concentration-response studies with two H2 antagonists, cimetidine and ranitidine., Results: Continuous perfusion with cimetidine at the highest concentration (10 microM) reduced the incidence of ischaemia-induced VF from 57% in controls to 8% (P < 0.05) and the incidence of reperfusion-induced VF from 78 to 38% (P < 0.05). Surprisingly, the incidences of ischaemia- and reperfusion-induced arrhythmias were not reduced by ranitidine over an equivalent concentration range (0.1-10 microM). Electrocardiographic (ECG) variables (PR and QT interval) were not altered by cimetidine or ranitidine at any concentration, suggesting that neither drug produced direct electrophysiological actions on fast inward sodium, L-type calcium or potassium currents (blockade of which would have led to ECG changes)., Conclusion: Ranitidine does not possess antiarrhythmic activity during ischaemia or reperfusion in the isolated rat heart, indicating that specific H2 antagonism is unlikely to be an effective mechanism of VF suppression. Thus, if histamine functions as an arrhythmogenic factor, it is not likely to do so by activating H2 receptors. Furthermore, since ranitidine is marginally the more potent of the two drugs as an H2 antagonist, it would appear that cimetidine, which was found to protect against VF, possesses antiarrhythmic activity mediated by non-specific effects (i.e., not attributable to blockade of H2 receptors).

It has been proposed that NO may function as an endogenous cardioprotectant. We have investigated whether modulation of NO levels (detected in coronary effluent by chemiluminescence) by a blocker of its synthesis, by supplementation of its precursor, and by administration of an NO donor can influence reperfusion arrhythmias in the isolated rat heart. Rat hearts were perfused with modified Krebs' solution and subjected to 5, 35, or 60 minutes of left regional ischemia followed by 10 minutes of reperfusion. NG-Nitro-L-arginine methyl ester (L-NAME), which blocks NO synthase, increased the incidence of reperfusion-induced ventricular fibrillation (VF) from 5% in the control condition to 35% after 60 minutes of ischemia (n = 20, P < .05). The profibrillatory effect of L-NAME was prevented in hearts coperfused with 1 or 10 mmol/L L-arginine (an NO precursor) but persisted in hearts coperfused with D-arginine (1 mmol/L). L-NAME did not increase VF susceptibility in hearts reperfused after 5 or 35 minutes of ischemia. L-NAME caused sinus bradycardia (264 +/- 10 versus 309 +/- 5 bpm in control groups, P < .05) and reduced coronary flow before ischemia (6.2 +/- 0.6 versus 9.2 +/- 0.6 mL.min-1.g-1 tissue in controls, P < .05). L-NAME reduced coronary effluent NO levels after 60 minutes of ischemia; during the first minute of reperfusion, values were reduced from 1457 +/- 422 to 812 +/- 228 pmol.min-1.g-1 (P < .05). This effect was prevented by coperfusion with L-arginine (10,344 +/- 1730 pmol.min-1.g-1, P < .05).(ABSTRACT TRUNCATED AT 250 WORDS)

A bioactivity-directed fractionation of the root-and stem-barks of Enantia chlorantha resulted in the isolation of palmatine chloride 1 and jatrorrhizine chloride 2 as the major antimicrobial constituents. MIC determinations indicated that these compounds were superior to those of well established broad spectrum antibiotics against some of the organisms used.

Theophylline and related xanthines have been used in the treatment of airways diseases such as bronchial asthma for over 50 years. The therapeutic effectiveness of this class of drugs was traditionally thought to be derived from their ability to elicit bronchodilation, however evidence is accumulating to suggest that theophylline in particular possesses immunomodulatory and anti-inflammatory activity. The molecular mechanisms of action of theophylline have not yet been clarified, although several putative mechanisms of action have been proposed. One of these suggests that theophylline via non-selective inhibition of the phosphodiesterase (cAMP) and cyclic guanosine monophosphate (cGMP) levels resulting in relaxation of airway smooth muscle and inhibition of inflammatory cell activation. To date seven different families of the PDE enzyme have been defined according to a variety of criteria including substrate specificity, sensitivity to selective inhibitors and the effect of allosteric modulators. The type IV isoenzyme is the predominant isoenzyme in most inflammatory cells. This article reviews some of the in vitro, in vivo and clinical studies which have demonstrated that theophylline and selective PDE inhibitors possess anti-inflammatory and immunomodulatory activity.

We tested the hypothesis that blockade of the ATP-sensitive K+ channel (IK(ATP)) is an antiarrhythmic mechanism in acute myocardial ischaemia, using an opener of the channel (10 microM RP 49356, RP) and a blocker of the channel (10 microM glibenclamide, GL) and a combination of the two drugs (GL+RP, 10 microM each) in a randomised blinded study. Isolated rat hearts (n = 8 per group) were subjected to 30-min left regional ischaemia. GL and GL+RP widened QT interval after 10-min ischaemia (197 +/- 39 and 203 +/- 20 ms, respectively vs. 154 +/- 12 ms in controls), whereas RP significantly shortened QT interval (123 +/- 6 ms). GL and GL+RP decreased coronary flow (p < 0.05). RP caused slight increase in flow during ischaemia. These effects are all consistent with modulation of vascular and cardiac IK(ATP). RP alone had no effect on ischaemia-induced arrhythmias. Neither did GL have any effect on the incidence of ventricular fibrillation (VF: 88 vs. 100% in controls). However, GL reduced the incidence of sustained VF (VF lasting continuously for > 2 min) to 14% vs. 88% in controls (p < 0.05). Therefore, GL had defibrillatory activity. Surprisingly, in view of these findings, the GL+RP combination significantly reduced the incidence of VF to 25% (from 100% in control hearts, p < 0.05) i.e., had an antifibrillatory effect. So, two agents that produce pharmacological effects attributable to block and opening of IK(ATP) when administered singly had no effects on the incidence of ischaemia-induced VF.(ABSTRACT TRUNCATED AT 250 WORDS)

Theophylline has been in clinical use for the treatment of bronchial asthma and other respiratory diseases for well over 50 yrs. Over this time, a considerable body of evidence has accumulated to show that this drug has a wide range of pharmacological actions, in addition to the well-recognized action on airway smooth muscle function. Current evidence suggests that part of the therapeutic value of theophylline in the treatment of asthma is by virtue of an anti-inflammatory or immunomodulatory effect, although the actual mechanism of action remains unclear. It has been proposed that the observed anti-inflammatory effects of theophylline could be attributed to phosphodiesterase (PDE) inhibition, and recently the type III and IV isoenzymes have been characterized in a number of inflammatory cells. This article reviews the evidence that theophylline and the newer more selective type IV PDE isoenzyme inhibitors can inhibit the activation of inflammatory cell types, such as T-lymphocytes, eosinophils, mast cells and macrophages, in vitro. The evidence supporting the ability of theophylline and selective PDE IV isoenzyme inhibitors to modify allergic inflammation both in animal models and clinical asthma is also discussed. We conclude that theophylline possesses important anti-inflammatory and immunomodulatory activity and that, in light of this evidence, it is timely to reconsider the place of theophylline in the treatment of asthma.

We have investigated the in vitro hamster hepatic microsomal metabolism of the amino-azaheterocycle, 2-amino-1-benzylbenzimidazole (ABB). Three major metabolites were isolated and structurally characterized, using a combination of off-line HPLC, in conjunction with both electron ionization and fast atom bombardment ionization tandem mass spectrometry. ABB was shown to be debenzylated to afford 2-aminobenzimidazole (AB), as well as N- and C-oxidized to give 1-benzyl-N2-hydroxyaminobenzimidazole (BHB) and 2-amino-1-benzyl-hydroxybenzimidazole, respectively. The possible reasons for formation of the exocyclic hydroxylamine BHB are discussed. Furthermore, ABB is proposed as a suitable model compound for investigating parameters that control formation of toxic hydroxylamines derived from amino-azaheterocycles.

EPR spectroscopy was used to investigate the cytochrome P-450-dependent steroid hydroxylase ecdysone 20-mono-oxygenase of the cotton leafworm (Spodoptera littoralis) and the redox centres associated with membranes from the fat-body mitochondrial fraction. Intense features at g = 2.42, 2.25 and 1.92 from oxidized mitochondrial membranes have been assigned to the low-spin haem form of ferricytochrome P-450, probably of ecdysone 20-mono-oxygenase. High-spin cytochrome P-450 (substrate-bound) was tentatively assigned to a signal at g = 8.0, which was detectable from membranes as prepared. An EPR signal characteristic of a [2Fe-2S] cluster detected from the soluble mitochondrial matrix fraction has been shown to be distinct from the signals associated with mitochondrial NADH dehydrogenase and succinate dehydrogenase, and has therefore been attributed to a ferredoxin. We conclude that the S. littoralis fat-body mitochondrial electron-transport system involved in steroid 20-hydroxylation comprises both ferredoxin and cytochrome P-450 components, and thus resembles the enzyme systems of adrenocortical mitochondria. EPR signals characteristic of the respiratory chain were also observed from fat-body mitochondria and assigned to the iron-sulphur clusters associated with Complex I (Centres N1, N2), Complex II (Centres S1, S3), Complex III (the Rieske centre), and the copper centre of Complex IV, demonstrating similarities to mammalian mitochondria. The reduced membrane fraction also yielded a major resonance at g = 2.09 and 1.88 characteristic of the [4Fe-4S] cluster of electron-transferring flavoprotein: ubiquinone oxidoreductase. As the fat-body is the major metabolic organ of insects, this protein is presumably required for the beta-oxidation of fatty acids in mitochondria. High-spin haem signals in the low-field region of spectra also demonstrated that the mitochondrial fraction contains relatively high concentrations of catalase.

Nurses will often be at the forefront in a health care team which decides that it is ethically acceptable to allow a particular patient to die but the possibility of actually killing another patient who requests his own death is met with heartfelt resistance. This paper explores the distinction between killing and letting die and the connection these arguments have with justifications for euthanasia. Two practical examples of killing and letting die are analysed. Various issues are examined including the active-passive distinction, the difference between causing and preventing a death and the probability of outcome. Justifications for euthanasia are then revisited and some concluding remarks made.

The aim of this study was to explore the validity of the nursing quality assessment instruments, Monitor, Senior Monitor and Qualpacs. This follows recommendations in the literature for the need for more comprehensive validation of instruments than has been the case hitherto. A multiple triangulation research design was used which included observation of and interviews with nurses and patients as well as administration of the instruments with the same patients and a questionnaire completed by the nurses in charge on ward organisation and their approach to nursing care. Results reported here focus on our experiences of using the instruments, their inter-rater reliability and comparisons of instrument scores within medical, surgical and elderly care wards. Difficulties were encountered in using the instruments but most of these can be overcome given sufficient time for preliminary discussions. Inter-rater reliability of all three instruments taken as a whole reached acceptable levels, although some of the section score correlation coefficients were low, especially for Qualpacs. Convergent validity was achieved for the Senior Monitor-Qualpacs comparisons in four elderly care wards. The results were less clear for the Monitor-Qualpacs comparisons in seven medical and surgical wards. Explanations for the equivocal results are suggested and subsequent hypotheses were tested which supported these explanations.

We examined the effects of the heparin ion-pair complex ITF 1300 on ventricular fibrillation (VF) and other arrhythmias elicited by regional ischemia and by reperfusion in isolated rat hearts (n = 12 per group). During 30-min ischemia, 1, 3, and 10 mg/L ITF 1300 reduced the incidence of VF concentration dependently, with complete abolition of VF at the highest concentration (p < 0.05). Similar but weaker effects were observed for other arrhythmias [ventricular tachycardia (VT) and salvos]. Reperfusion-induced arrhythmias (elicited after 10- or 30-min regional ischemia) were affected similarly, with complete abolition of VF at the highest drug concentration (p < 0.05). Coronary blood flow (CBF), recovery of CBF during reperfusion, and occluded zone sizes were little affected (p = NS). ITF 1300 caused concentration-dependent bradycardia, PR interval widening, and QT widening. In further studies, we examined the roles of these changes in mediating the antiarrhythmic effects. Left atrial pacing at a rate close to control rate (300 beats/min) abolished the antiarrhythmic effects of ITF 1300 and the QT widening, indicating that bradycardia and QT widening were important in mediating the antiarrhythmic effects. Doubling the calcium concentration in the perfusion solution prevented ITF 1300-induced PR widening, indicating that calcium antagonist activity probably mediated the drug's effects on this variable. However, the antiarrhythmic effect of ITF 1300 was not affected by high calcium perfusion. ITF 1300 is an effective antiarrhythmic agent in a model of ischemic heart disease. Its effects are mediated primarily by heart rate-dependent QT widening and were not related to possible calcium antagonist activity.

Aerosolized unfractionated heparin GM1060 significantly inhibited allergen-induced eosinophil infiltration into the airways of guinea-pigs (as assessed both histologically and by bronchoalveolar lavage, or BAL) at doses of 160 and 1600 U/ml. Similarly aerosolized unfractionated heparin, Multiparin was effective at reducing eosinophil levels in the BAL fluid at 1000, 2000 and 5000 U/ml, but this reduction was statistically significant only at the highest dose used. Additionally, Fragmin (a low molecular weight heparin) significantly inhibited allergen-induced eosinophil infiltration into BAL fluid at a dose of 500 U/ml, an effect that was lost at the higher doses of 1000 and 2000 U/ml. Allergen-induced eosinophil infiltration was unaffected by dermatan sulphate. However, the glycosaminoglycans chondroitin sulphate A, chondroitin sulphate C and heparan sulphate were able to influence the extent of allergen-induced eosinophil infiltration into BAL fluid. These results suggest that heparin and some related glycosaminoglycans can inhibit allergen-induced eosinophil infiltration when administered directly to the airways.

Three orally active iron chelating agents from the 3-hydroxypyridin-4-one series of compounds were administered by gavage to both normal and iron-overloaded (500 mg Fe/kg) rats at a dose of 450 mumol/kg to investigate the effect of iron loading on metabolism and urinary recovery. Compounds selected for investigation were either poorly metabolized [1-(2'-hydroxyethyl) derivative, CP102] or predominantly biotransformed by either phase I [1,2-diethyl derivative, CP94] or phase II (1,2-dimethyl derivative, CP20) metabolic pathways. Unchanged drug and metabolite(s) recovered in urine were determined by HPLC and iron levels by atomic absorption spectrometry. Significant differences in recovery of unchanged drug were seen for both CP20 (L1) and CP94 between normal and iron-overloaded animals. In contrast, no such difference was seen for the poorly metabolized compound, CP102. For CP20 (L1), the proportion of unchanged drug excreted in the urine increased from 36.2 +/- 9.9% in normal animals to 78.7 +/- 8.1% (p < or = 0.02) in iron-loaded animals and 20.1 +/- 4.5% to 39.9 +/- 8.6% for CP94 (p < or = 0.05). A significant decrease in metabolite recovery of CP20 (L1) was seen with the 3-O-glucuronide conjugate decreasing from 38.2 +/- 8.8% in normal animals to 2.5 +/- 2.0% in the iron-overloaded group. The decrease of the 2-(1'-hydroxyethyl) metabolite of CP94 from 41.4 +/- 6.6% to 29.4 +/- 4.6% in the iron-loaded animals was, however, not statistically significant. Total dose recovered in the urine between normal and iron-overloaded animals was only significant for CP94 (p < or = 0.05).

Our aim was to determine whether daily exposure to 4 ppm nitrogen dioxide (NO2) from birth until 3 months of age influenced the development of airways hyperresponsiveness and atopic sensitivity in immunized rabbits. Littermate New Zealand white (NZW) rabbits were immunized within 24 h of birth by i.p. injection of house dust mite antigen in AI(OH)3 gel, and exposed to either ambient air or 4 ppm NO2 for 2 h.day-1, 5 days.week-1. At 3 months, bronchoalveolar lavage (BAL) and serum samples were obtained. Airways responsiveness was measured as the provocative concentrations (mg.ml-1) of histamine or methacholine required to elicit a 50% increase in airway resistance (RLPC50) and a 35% decrease in dynamic compliance (CdynPC35). There were no differences in total cell or differential cell counts recovered in BAL fluid between control and NO2 exposed animals. Airways responsiveness did not differ between groups of animals (histamine RLPC50 values: air (n = 15) versus NO2 (n = 13), respectively, 9.98 +/- 1.32 versus 16.43 +/- 1.45 mg.ml-1; CdynPC35 values: 16.60 +/- 1.44 versus 14.95 +/- 1.43 mg.ml-1; methacholine RLPC50 values: air (n = 14) versus NO2 (n = 12), respectively, 2.18 +/- 1.51 versus 2.21 +/- 1.32 mg.ml-1; CdynPC35 values: 2.64 +/- 1.41 versus 2.85 +/- 1.31 mg.ml-1). There was no difference in sensitization between groups of animals exposed to air or NO2, evaluated either by cutaneous responsiveness to intradermal antigen, or serum immunoglobulin E (IgE) levels assessed by the passive cutaneous anaphylaxis (PCA) reaction.(ABSTRACT TRUNCATED AT 250 WORDS)

Critical incident analysis has been espoused as a valuable method of promoting reflective nursing practice and as a tool for developing curriculum content. Despite an obvious application to mental health nursing, however, there has been little detailed examination of the practicalities and educational value of critical incident analysis within a mental health nursing curriculum. This paper is based on the use of critical incident analysis within the mental health branch of a Project 2000 diploma course. It presents the content of material brought by students, teaching methods used to facilitate learning, and the progressive development of students' reflective processes over the course of a complete branch programme. Using Benner's (1984) From Novice to Expert, the authors explore questions regarding the nature and effects of the critical incident technique in attaining competence in mental health nursing skills. The authors conclude with a theory-based evaluation and analysis of this student-centered experiential approach to learning as a method for developing reflective practice, and suggest areas for educational research.

This study investigated the effects of mycoprotein, a food produced by the continuous fermentation of Fusarium graminearum (Schwabe), on acute glycemia and insulinemia in normal healthy individuals. Subjects participated in two single-meal study periods in a crossover design. After an overnight fast, subjects were given milkshakes containing mycoprotein or a control substance, which were isoenergetic and nutrient balanced. Each milkshake contained 75 g carbohydrate, equivalent to a standard World Health Organization oral-glucose-tolerance test. Blood samples were taken fasting and at 30, 60, 90, and 120 min postprandially for the measurement of serum glucose and insulin. Glycemia was reduced postmeal after mycoprotein compared with the control and was statistically significant at 60 min (13% reduction). Insulinemia was reduced postmeal after mycoprotein compared with the control and was statistically significant at 30 min (19% reduction) and 60 min (36% reduction) postmeal. These results may be significant in the dietary treatment of diabetes.

A number of iron-chelating agents are currently being considered as orally active alternatives to desferrioxamine (DFO), the therapeutic agent for the treatment of body iron overload that is available at present. These include bidentate hydroxypyridinones (HPO), tridentate desferrithiocin (DFT) analogues and hexadentate aminocarboxylate (HBED) chelators. All chelating agents have the potential to induce toxic effects when iron homoeostasis is affected within the body. This can arise when the absorption, distribution and utilization of iron is affected. Alternatively, chelating agents can induce toxicity by directly interfering with iron-dependent metalloenzymes located within the body. These effects are, however, mainly localized to non-haem enzymes such as ribonucleotide reductase and lipoxygenase. The resultant iron complexes also have the ability to induce toxicity. Depending on the coordination geometry and donor atoms associated with the metal centre, redox cycling of the iron centre with the corresponding generation of free radicals can result.

The effect of 7-nitro indazole (7-NI) and a range of substituted indazole derivatives on nitric oxide synthase (NOS) enzyme activity in homogenates of rat cerebellum, bovine endothelial cells and lung from endotoxin-pretreated rats was investigated. 3-bromo 7-nitro indazole was either equipotent (IC50, 0.86 +/- 0.05 microM c.f. 0.78 +/- 0.2 microM, n = 6, P > 0.05) or approximately 4x (IC50, 0.17 +/- 0.01 microM c.f. 0.71 +/- 0.01 microM, n = 6, P < 0.05) or 20x (IC50, 0.29 +/- 0.01 microM c.f. 5.8 +/- 0.4 microM, n = 6, P < 0.05) more potent than 7-NI as an inhibitor of bovine endothelial, rat cerebellar and rat lung NOS enzyme activity respectively. 2,7-dinitro indazole also inhibited NOS in all three tissue sources with a potency similar to that of 7-NI. These results suggest that 3-bromo 7-NI and 2,7-dinitro indazole may prove to be useful additional tools with which to examine the biological properties of nitric oxide (NO).

Co-administration of the nitric oxide synthase inhibitor, 7-nitro indazole (1 mg/kg i.p.), with the cyclooxygenase inhibitor, flurbiprofen (5-75 mg/kg i.p.), resulted in significantly enhanced antinociceptive activity in mice (formalin-induced hindpaw licking assay) without affecting hindpaw inflammation. No antinociception was observed in animals pretreated with 7-nitro indazole (1 mg/kg i.p.) and flurbiprofen (100 micrograms subplantar). Flurbiprofen (50 mg/kg i.p.) pretreatment did not influence the inhibition of cerebellar or spinal cord nitric oxide synthase activity observed after 7-nitro indazole (1 or 25 mg/kg i.p.) administration and did not alter blood pressure in anaesthetised animals. Thus, flurbiprofen acts by a mechanism unrelated to a local anti-inflammatory effect in the hindpaw. Since nitric oxide synthase inhibitors are antinociceptive by an effect in the spinal cord (dorsal horn) this would appear to be a likely location for the nitric oxide synthase and cyclooxygenase enzymes targetted by 7-nitro indazole and flurbiprofen respectively.

This paper reviews evaluative studies on the role of clinical nurse specialists and aims to describe and categorise research according to the methods used. By using the structure, process and outcome framework a clear pattern of research development and evidence emerges. It appears that significant benefits accrue for patients from the contribution of nurse specialists, but more experimental studies with combined methods should now be applied to this area.

The UKCC Code of Professional Conduct for nurses, midwives and health visitors stresses the need to have an understanding of the social and cultural determinants of health and illness. There is as yet little evidence of what might constitute good practice in this area and it is difficult to ascertain why this basic philosophy is not translated into action. Indeed, the nursing and midwifery professions' ability to deliver adequate and appropriate health care more generally to Britain's multiracial, multicultural population has been questioned. This literature review presents evidence which strongly suggests that although we are living in a multicultural society patients from minority ethnic groups are additionally disadvantaged because the initiatives by nurses, and others working in the National Health Service, to meet their health care needs are inadequate and often inappropriate.

Tamoxifen, 4-hydroxytamoxifen, nafoxidine, 17 beta-oestradiol and ICI 164,384 were all found to protect rat liver nuclei against Fe(III)-ascorbate dependent lipid peroxidation. The order of effectiveness of these compounds was 4-hydroxytamoxifen > 17 beta-oestradiol > nafoxidine > tamoxifen > ICI 164,384. This protection by tamoxifen against the formation of the genotoxic reactive-intermediates and products of lipid peroxidation in the nuclear membrane could be important in the prevention of nuclear DNA damage and thus carcinogenesis. This possible anticarcinogenic benefit of tamoxifen treatment could be important in long-term therapy with tamoxifen (and future derivatives) and in its proposed use in the prevention of breast cancer.