Glial aromatization decreases neural injury in the zebra finch (Taeniopygia guttata): influence on apoptosis.

Emerging evidence suggests a neuroprotective role for oestrogens following damage to the vertebrate brain. Aromatase (oestrogen synthase) is rapidly transcribed and translated in glial cells around areas of neural damage in several vertebrates. However, the potential neuroprotection afforded by locally up-regulated glial aromatase immediately surrounding the injury remains to be tested. Towards this end, individual birds sustained penetrating mechanical injuries via a needle that contained either vehicle or the aromatase inhibitor fadrozole into contralateral hemispheres. Seventy-two hours later, the size of neural injury (as assessed by the extent of necrotic tissue) and the number of apoptotic cells around the injuries were evaluated. The size of injury in the hemisphere injected with fadrozole was significantly larger than the injury caused by vehicle injection. Furthermore, a greater number of apoptotic nuclei were found around the fadrozole-associated lesion relative to vehicle. Finally, constitutively expressed, neuronal aromatase close to the injury site did not differ between hemispheres. We conclude that local inhibition of glial aromatase immediately around the site of injury plays a neuroprotective role in the songbird brain and this protection involves apoptotic pathways. Local up-regulation of glial aromatase may play a pivotal role in the limitation of secondary damage and/or the acceleration of restorative processes following injury to the vertebrate brain.

Effects of concurrent administration of flosequinan and digoxin on the pharmacokinetics of each drug.

The pharmacokinetic and pharmacodynamic effects of co-administration of flosequinan (BTS 49465, CAS 76568-02-0) and digoxin (CAS 20830-75-5) were investigated in 12 healthy volunteers. A 4-day, open, lead-in phase established the pharmacokinetics of flosequinan (100 mg on the first day and 50 mg for the next 3 days) and was followed by a 24-day open interaction phase. Digoxin was administered alone (0.75 mg for the first 3 days and 0.5 mg for the next 4 days) to establish steady-state pharmacokinetics and in combination with flosequinan (100 mg on the 8th day and 50 mg for the next 14 days with 0.5 mg digoxin daily), and finally digoxin alone (0.5 mg for the remaining 3 days). No statistically significant differences were observed for any of the pharmacokinetic parameters for flosequinan, its major metabolite BTS 53554, or digoxin when flosequinan and digoxin were administered alone or concomitantly, but the confidence intervals for differences were relatively wide. Overall diastolic blood pressure was significantly lowered by 10% with concomitant treatment compared with flosequinan monotherapy. There were no significant effects on overall heart rate or systolic blood pressure, although pre-dose heart rate was increased by 6% during concomitant administration compared with digoxin alone, and remained high and digoxin alone. Adverse events (headache, nausea and vomiting) were reported by 2 volunteers on digoxin and 5 on concomitant therapy. One volunteer was withdrawn during concomitant therapy because of severe headache and vomiting. The results from this study indicate that no pharmacokinetic interaction occurred during concomitant administration of flosequinan and digoxin in healthy volunteers.

A non-invasive evaluation of flosequinan on haemodynamics and exercise capacity in chronic congestive heart failure.

The efficacy of flosequinan 100 mg once daily was evaluated in 15 patients with severe congestive heart failure (New York Heart Association [NYHA] class II-IV) who had not responded adequately to digoxin and diuretics. Efficacy assessments using non-invasive techniques included exercise capacity, haemodynamics and left ventricular function. Determinations were made after 3 and 21 days' treatment, and compared with baseline. Flosequinan significantly increased exercise capacity by 27% after 3 days (+79 seconds, p = 0.015) and by 43% after 21 days (+123 seconds, p = 0.0007) and was accompanied by an increase in heart rate (+7.2 beats/min, p = 0.03; +9.1 beats/min, p = 0.03, respectively). Cardiac index and cardiac output were also significantly increased but only after 21 days' treatment (+0.3 l/min/m2, +16% and +0.5 l/min, +14%, respectively; both p = 0.008). Flosequinan was well tolerated, with headache being the most frequently reported adverse event and only 1 patient being withdrawn. One patient died but this was not unexpected in a group of patients with severe heart failure. Using non-invasive techniques this study demonstrated that in patients with severe chronic congestive heart failure, flosequinan increased exercise capacity and cardiac output, the latter being achieved mainly by an increase in heart rate.

A comparison of the effects of captopril and flosequinan in patients with severe heart failure.

Angiotensin converting enzyme inhibitors have greatly improved the treatment of patients with chronic heart failure but they are not effective in all patients, and their use may be limited by side effects. There is, therefore, a need to investigate new drugs and to compare their efficacy with angiotensin converting enzyme inhibitors. Flosequinan is a new direct-acting vasodilator that has been shown to be effective in placebo-controlled studies. Patients with chronic heart failure in NYHA classes II or III who remained symptomatic despite at least 80 mg of frusemide daily were recruited from two centers. Following a single-blind placebo run-in period, the patients were randomized double blind to either the addition of captopril or flosequinan for 6 weeks. Following a further 2-week placebo washout period, they were then given the alternative treatment. Symptom-limited treadmill exercise times, scores of perceived exertion, and corridor walk tests were measured at two weekly intervals during the study. Twenty-five patients entered the study, 16 of whom completed without a change in diuretic dose. Five patients were withdrawn while taking captopril and two while taking flosequinan; two were withdrawn during the placebo washout period. For those patients who completed the study, flosequinan increased treadmill exercise tolerance from a mean (SEM) placebo time of 11.5 (1.0) minutes by 2.4 (0.6) (p = 0.0002) and captopril from 12.0 (0.8) minutes by 1.2 (0.6) minutes (p = 0.08). Comparison of the other measures of efficacy revealed no difference between the groups. In this short-term study flosequinan appeared to be equal in efficacy to captopril.

Renal excretory actions of furosemide, of hydrochlorothiazide and of the vasodilator flosequinan in healthy subjects.

The responses of urine and urinary solute outputs and flows to single doses of 80 mg furosemide, 25 mg hydrochlorothiazide, and 100 or 200 mg flosequinan were investigated in healthy subjects using a double-blind, randomized, crossover design. Treatment days were separated by 7 days. Volumes of urine passed between 0 and 3, 3 and 6, 6 and 9, 9 and 12, and 12 and 24 h after drug administration were determined and urinary concentrations of chloride, sodium, potassium, calcium, magnesium, phosphate, zinc, urate, urea and creatinine were measured. Venous blood was taken before and 6 and 24 h after dosing and the serum was analysed for the same solutes as urine. Excretions of urine and urinary solutes accumulated at the end of each collection period after each formulation were fitted by the UY function, whose derivative provided corresponding flows as functions of time. Instantaneous renal clearances of solutes 6 and 24 h after dosing were evaluated from the flows. This approach showed that 80 mg furosemide and 25 mg hydrochlorothiazide were equipotent 24-h natriuretics. Rapid urinary responses which then rebounded compared with the control responses were produced by 80 mg furosemide, whereas changes after 25 mg hydrochlorothiazide were smooth. Neither 100 or 200 mg flosequinan showed any important effect on urinary excretion.

Effect on radiolabelled-monoamine uptake in vitro of plasma taken from healthy volunteers administered the antidepressant sibutramine HCl.

Sibutramine HCl, a monoamine reuptake inhibitor type of antidepressant, was administered to healthy male volunteers as either a single dose (12.5 or 50 mg) or repeated treatment (5-20 mg once daily or 15 mg twice daily). Plasma, obtained at regular intervals during and after sibutramine HCl or placebo treatment, was assayed in vitro for its ability to inhibit the uptake of [3H]-noradrenaline (NA) by rat cortical synaptosomes, [3H]-5-hydroxytryptamine (5HT) by human platelets and [14C]-dopamine (DA) by rat striatal synaptosomes. After both single and repeated sibutramine HCl administration, the rank order of uptake inhibition was [3H]-NA greater than [3H]-5HT greater than [14C]-DA. The level of monoamine uptake inhibition increased on daily administration to a plateau 4-6 days after initiation of treatment, for example, approximately 60% and 40% inhibition of [3H]-NA and [3H]-5HT, respectively, following 15 mg sibutramine HCl twice daily. The pattern of monoamine uptake inhibition following sibutramine HCl administration to man is similar to that observed in sibutramine HCl-treated rats, and probably at least partly reflects inhibition of uptake by drug metabolites in both species. The inhibition of monoamine uptake following sibutramine HCl administration to man is consistent with an antidepressant effect.

Comparison of the effects of captopril and enoximone in patients with severe heart failure: a placebo controlled double-blind study.

The effects of enoximone, a new cyclic adenosine monophosphate phosphodiesterase inhibitor, were compared with those of captopril in a double-blind study in a group of 10 patients with severe heart failure. Four weeks treatment with enoximone improved symptom-limited exercise tolerance from a mean value of 11.33 to 13.36 minutes (P less than 0.05) and 4 weeks of captopril treatment from 11.01 to 13.92 minutes (P less than 0.05). Four of the patients had a greater exercise tolerance taking enoximone, the remaining 6 while taking captopril. Both drugs reduced perceived exertion during submaximal exercise. Minute ventilation measured at rest and during submaximal exercise was also reduced by both drugs. Resting and post exercise calf blood flow was increased to a similar extent with captopril (P less than 0.03) and enoximone (P less than 0.005). There was no difference in calf blood flow and calf vascular resistance between the drugs suggesting that the peripheral haemodynamic effects of enoximone are due to peripheral vasodilatation. Enoximone is a useful drug for the treatment of patients with severe heart failure.

The effect of flosequinan in patients with acute-onset heart failure complicating acute myocardial infarction.

We studied the hemodynamic effect of a single dose of the new direct-acting vasodilator, flosequinan, in 25 patients with severe acute-onset heart failure complicating acute myocardial infarction, which was resistant to high doses of diuretics, nitrates and dobutamine given intravenously. Flosequinan was added to conventional therapy within 3.7 +/- 0.8 days of the infarction in the form of a single oral dose of 100 mg. Hemodynamic monitoring was performed every hour for 4 hours after the administration, without any other drug being added. Flosequinan produced hemodynamic improvement in all patients. The effect peaked at 1 to 2 hours and remained at this level at 4 hours. Pulmonary capillary wedge pressure decreased from 28.4 +/- 4.5 to 17.8 +/- 5.7 mmHg and cardiac output increased from 3.5 +/- 0.3 to 4.0 +/- 0.4 L/min (p less than 0.05 for both). Pulmonary arterial and pulmonary vascular resistances were also significantly reduced. Heart rate was not significantly altered. Mean systemic arterial pressure was slightly but not significantly reduced. Administration of flosequinan was not associated with symptomatic hypotension, cardiac arrhythmias or other adverse events and the hemodynamic effect was not related to the pre-treatment serum sodium concentration. We conclude that flosequinan is effective in producing acute hemodynamic improvement in patients with heart failure complicating acute myocardial infarction which is resistant to conventional therapy. Flosequinan is well tolerated in this group of patients and therefore further studies to determine the duration of action of the drug in this condition are appropriate.

Effect of flosequinan in patients with acute-onset heart failure complicating acute myocardial infarction.

We studied the hemodynamic effect of a single dose of the new direct-acting vasodilator, flosequinan, in ten patients with severe acute-onset heart failure complicating acute myocardial infarction (MI) resistant to high iv doses of diuretics, nitrates, and dobutamine. Flosequinan was added to conventional therapy at 3.8 +/- 0.5 days after infarction in the form of a single 100-mg oral dose. Hemodynamic measurements were performed every hour for 4 h after administration, without any other drug being added. The nitrate infusion rate was kept constant. Flosequinan produced hemodynamic improvement in this group. The effect peaked at 1 to 2 h and remained at this level at 4 h. Pulmonary capillary wedge pressure decreased from 27.2 +/- 5.4 to 16.4 +/- 3.0 mm Hg, and cardiac output increased from 3.5 +/- 0.3 to 4.1 +/- 0.4 L/min (p less than .001 for both). Cardiac index, stroke index, and left ventricular stroke work index were significantly increased. Pulmonary arterial and right atrial pressures, and systemic and pulmonary vascular resistances were also significantly reduced. Heart rate was not significantly altered. Mean systemic arterial pressure was slightly reduced. Flosequinan administration was not associated with symptomatic hypotension, cardiac arrhythmias, or other adverse events, and the hemodynamic effect was not related to the pretreatment serum sodium concentration. We conclude that flosequinan is effective in producing acute hemodynamic improvement in patients with heart failure complicating acute MI resistant to conventional therapy.

The effect of flosequinan in patients with heart failure of acute onset complicating acute myocardial infarction.

We studied the hemodynamic effect of a single dose of the new direct-acting vasodilator, flosequinan, in 18 patients with severe heart failure of acute onset complicating acute myocardial infarction, which was resistant to high doses of diuretics, nitrates and dobutamine given intravenously. Flosequinan was added to conventional therapy at 3.5 +/- 0.8 days from the infarction, in the form of a single oral dose of 100 mg. Hemodynamic measurements were performed every hour for 4 hours after the administration, without any other drug being added. The infusion rate of nitrates was kept constant. Flosequinan produced hemodynamic improvement in this group. The effect peaked at 2 hours and remained at this level at 4 hours. Pulmonary capillary wedge pressure decreased from 27.6 +/- 4.3 to 16.8 +/- 2.8 mm Hg and cardiac output increased from 3.5 +/- 0.3 to 4.1 +/- 0.4 l/min (P less than 0.001). Pulmonary arterial and right atrial pressures and systemic and pulmonary vascular resistances were also significantly reduced. Heart rate and mean systemic arterial pressure were not significantly altered. Administration of flosequinan was not associated with symptomatic hypotension, cardiac arrhythmias or other adverse events. We conclude that flosequinan is effective in producing acute hemodynamic improvement in patients with heart failure, complicating acute myocardial infarction, which is resistant to conventional therapy. Flosequinan is safe and well tolerated. Studies for longer time periods are indicated.

Efficacy and safety of flosequinan, given over 3 days, evaluated by continuous hemodynamic monitoring.

The hemodynamic effects of flosequinan, a new balanced vasodilator, were evaluated in 12 patients with chronic congestive heart failure. The drug was added to diuretics and digitalis and given as an oral dose of 100 mg, once daily in the morning, over 3 days, and hemodynamic monitoring was performed before the first dose and for 72 h thereafter. Hemodynamic improvement, peaking between 1 and 2 h after oral administration, was observed on all 3 days. On day 1 pulmonary capillary wedge pressure (PCWP) was reduced from 27.8 +/- 8.6 to 13.0 +/- 3.1 mm Hg and cardiac output (CO) increased from 3.3 +/- 0.6 to 4.5 +/- 0.9 liters/min (p less than 0.05). After 12-16 h the effect was slightly attenuated but remained significant at 24 h. A similar response was observed after the doses given on days 2 and 3. At 72 h PCWP was 15.5 +/- 4.1 mm Hg and CO 3.8 +/- 1.1 liters/min (p less than 0.05 for the difference from baseline). Heart rate was slightly increased only at 2 h after the dose. Pulmonary arterial and right atrial pressure and systemic and pulmonary vascular resistances were significantly reduced (except for systemic resistance at 72 h). In conclusion, flosequinan produces hemodynamic improvement in patients with chronic congestive heart failure. The response to subsequent doses is similar to the response to the first dose.

Flosequinan induces hemodynamic improvement in heart failure complicating acute myocardial infarction.

The hemodynamic effects of a single dose of flosequinan, a new balanced vasodilator, were studied in twelve patients with severe acute onset heart failure complicating acute myocardial infarction. Flosequinan was added to conventional therapy within 3.8 +/- 0.5 days of the infarction, in the form of a single oral dose of 100 mg in ten of the patients. In the remaining two, reinfarction developed on the sixth day and they received flosequinan immediately thereafter. Hemodynamic monitoring was performed for four hours after the administration, without any other drug being given. Flosequinan produced hemodynamic improvement in all patients. The effect peaked at one to two hours and remained at this level at four hours. Pulmonary capillary wedge pressure decreased from 27.4 +/- 5.0 to 16.5 +/- 2.9 mm Hg and cardiac output increased from 3.5 +/- 0.3 to 4.1 +/- 0.4 l/min (p less than 0.001 for both). Pulmonary arterial and right atrial pressures and systemic and pulmonary vascular resistances were also significantly reduced. Heart rate was not significantly altered (from 84.0 +/- 4.5 to 87.4 +/- 4.6). Mean systemic arterial pressure was slightly reduced. Administration of flosequinan was not associated with any adverse effects and the hemodynamic effect was not related to the pre-treatment serum sodium concentration. We concluded that flosequinan can produce acute hemodynamic improvement in patients with heart failure, complicating acute myocardial infarction. The drug is well tolerated.

Flosequinan in heart failure: acute haemodynamic and longer term symptomatic effects.

There is no single, simple test with which to evaluate new treatments for heart failure. Various methods need to be used, and a study of both the acute haemodynamic and longer term symptomatic effects of flosequinan, a new direct acting arteriolar and venous vasodilator, was therefore carried out in patients with heart failure. In one group of patients flosequinan increased cardiac output and caused a fall in pulmonary capillary wedge pressure, both effects lasting for 24 hours. In a double blind, placebo controlled study in another group flosequinan improved mean exercise tolerance from 9.9 to 12.7 minutes after four weeks of treatment. The drug also reduced perceived exertion during submaximal exercise and increased calf and therefore skeletal muscle blood flow. It reduced plasma renin activity and noradrenaline concentrations. Flosequinan possesses all the important properties of a drug likely to be of value in the treatment of heart failure.

Flosequinan as a third agent for the treatment of hypertension: a placebo controlled, double-blind study.

The acute and short term antihypertensive effect of flosequinan was determined in 16 hypertensive patients whose blood pressure was inadequately controlled despite treatment with a beta-adrenoceptor blocking agent and a diuretic. Erect and supine systolic and diastolic blood pressure was significantly reduced by flosequinan over the treatment period as compared to placebo. Heart rate was unchanged by flosequinan. Adverse effects were limited to mild headache in 3 patients and taste disturbance in 1 patient, possibly due to salivary excretion of the drug. Flosequinan is a potentially useful vasodilator for the treatment of hypertension.

Symptomatic assessment of patients with heart failure: double-blind comparison of increasing doses of diuretics and captopril in moderate heart failure.

Ten patients with moderate heart failure who still had symptoms despite 40 mg frusemide daily were treated with increased doses of frusemide and the addition of captopril in randomised order. Four different methods were used to assess the patients' response to treatment. Both treatments improved symptom-limited exercise tolerance, higher-dose frusemide having a more favourable effect. Perceived exertion during submaximal exercise was reduced by similar amounts by both treatments. The time taken to walk 100 m at a self-selected slow speed was reduced by both treatments; again higher-dose frusemide had a more beneficial effect. The higher dose of frusemide also had a more favourable effect on visual analogue scores for dyspnoea, fatigue, and general well-being.

A placebo controlled comparison of the effects of pirenzepine and amitriptyline on the tyramine pressor test in healthy volunteers.

The possibility of an interaction between pirenzepine, an antimuscarinic drug structurally similar to the tricyclic antidepressants, and sympathomimetic agents was investigated in a group of healthy volunteers. The effect of pirenzepine on response to intravenous tyramine was compared with that of placebo and amitriptyline. The mean dose of tyramine required to elevate systolic blood pressure by 30 mm Hg was 5.0 mg (+/- s.d. 0.8) after placebo, 5.1 mg (+/- 1.0) after pirenzepine and 11.3 mg (+/- 1.8) after amitriptyline. These results suggest that pirenzepine will not potentiate the effects of concurrently administered sympathomimetic drugs.

The pharmacokinetics and haemodynamics of BTS 49 465 and its major metabolite in healthy volunteers.

The pharmacokinetic and haemodynamic effects of a 200 mg oral dose of BTS 49 465 (7-fluoro-1-methyl-3-methylsulphinyl-4-quinolone) were investigated in a double-blind placebo controlled study. BTS 49 465 was rapidly absorbed and cleared from the systemic circulation with a half-life of 1.6 h by oxidation to the sulphone metabolite. The metabolite was cleared with a half-life of 37.6 h. Saliva concentrations of both BTS 49 465 and its metabolite correlated well with the plasma concentrations. Compared to placebo, BTS 49 465 produced statistically significant reductions in blood pressure and increases in heart rate both supine and after a 60 degrees head up tilt. The time course of the haemodynamic changes suggested that the sulphone metabolite contributed to the overall hypotensive response. Plasma Renin Activity was only marginally elevated and there was no evidence of acute fluid retention. BTS 49 465 was well tolerated in terms of haematological and biochemical parameters and subjective side-effects.

The effects of BTS 49465 on blood pressure and peripheral arteriolar and venous tone in normal volunteers.

The pharmacokinetics and cardiovascular effects of a new vasodilator, BTS 49465 (7-fluoro-1-methyl-3-methylsulphinyl-4-quinolone) were evaluated in a double-blind placebo-controlled manner in a group of normal male volunteers. Forearm vascular resistance and forearm venous tone were measured by venous occlusion plethysmography using mercury-in-rubber strain gauges, supine, and in response to lower body negative pressure. Systemic arterial pressure was also measured. Dose-dependent reductions in blood pressure were observed both supine and in response to lower body negative pressure. Measurements of forearm vascular resistance and forearm venous tone suggested the drug caused both arteriolar and venous vasodilatation. Plasma level measurements indicated that the active metabolite of BTS 49465 had a prolonged half-life. BTS 49465 is a mixed arteriolar and venous vasodilator which may be suitable for once-daily administration. Measurement of limb vascular tone is a useful means of evaluating the effects of vasodilators.

Electrolyte secretion by the isolated cat pancreas during replacement of extracellular bicarbonate by organic anions and chloride by inorganic anions.

1. The effect of replacing extracellular bicarbonate and chloride by other anions on the volume and composition of secretin-stimulated pancreatic juice has been analysed in the isolated, perfused cat pancreas. 2. The anions of some aliphatic carboxylic acids were able partially to substitute for bicarbonate in sustaining pancreatic secretion. The order of effectiveness was: acetate greater than proprionate greater than butyrate greater than formate. 3. The rate of secretion in the presence of 25 mM-acetate was 42% of that achieved with 25 mM-bicarbonate. The concentration of acetate in the secretion varied with flow rate, reaching a maximum of 120 mM at high flow rates and declining at lower flow rates, with reciprocal changes in chloride concentration. Bicarbonate was always present in the secretion at a concentration of 5--7 mM. 4. Inorganic anions were able totally or partially to substitute for chloride in sustaining secretion. In relation to chloride, their degree of effectiveness was: chloride = bromide = or greater than nitrate greater than iodide greater than sulphate greater than methyl sulphate greater than isethionate. Those anions which had no effect on secretion rate (i.e. bromide and nitrate) also had no effect on the bicarbonate concentration of the secretion and themselves appeared in the secretion in place of chloride. Those anions which inhibited secretion increased the bicarbonate concentration in the secretion in proportion to the degree of inhibition they caused (i.e. the increase was greatest with isethionate). 5. When perfusate chloride was only partially replaced by bromide or iodide the ratios of chloride: bromide and chloride: iodide in the secretion were approximately equal to those in the perfusate. 6. The carbonic anhydrase inhibitor acetazolamide reduced secretory rate and bicarbonate concentration when added to normal perfusion fluid or chloride-substituted fluids, but had no effect following replacement of perfusate bicarbonate by acetate. 7. These observations illustrate that an extracellular source of permeant anions is required for optimal pancreatic bicarbonate secretion to occur. This may indicate the participation of an anion exchange carrier in the transport events responsible for this secretory process.