Distinct mechanism for antidepressant activity by blockade of central substance P receptors.

The localization of substance P in brain regions that coordinate stress responses and receive convergent monoaminergic innervation suggested that substance P antagonists might have psychotherapeutic properties. Like clinically used antidepressant and anxiolytic drugs, substance P antagonists suppressed isolation-induced vocalizations in guinea pigs. In a placebo-controlled trial in patients with moderate to severe major depression, robust antidepressant effects of the substance P antagonist MK-869 were consistently observed. In preclinical studies, substance P antagonists did not interact with monoamine systems in the manner seen with established antidepressant drugs. These findings suggest that substance P may play an important role in psychiatric disorders.

Blood pressure effects of the angiotensin II receptor blocker, losartan.

BACKGROUND: Losartan potassium, the first nonpeptide selective blocker of angiotensin II at the AT1 receptor, has been shown to exhibit clinical antihypertensive effects. The aim of the present study was to characterize the efficacy and duration of action of losartan by ambulatory blood pressure monitoring. METHODS: The study was performed in nonblack hypertensive patients whose baseline untreated clinical diastolic blood pressures were 95 mm Hg or higher and whose average 24-hour ambulatory diastolic blood pressures were 85 mm Hg or higher. Patients were randomized, double-blind, into four treatment groups: placebo (n = 32) or losartan, 50 mg once daily (n = 29), 100 mg once daily (n = 30), or 50 mg twice daily (n = 31). Clinical and 24-hour ambulatory blood pressures were measured at baseline (off treatment for at least 4 weeks) and after 4 weeks of treatment. RESULTS: By clinical sphygmomanometer measurements at the end of the 24-hour or 12-hour dosing intervals (trough), all three losartan dosages were significantly more effective than placebo at decreasing systolic and diastolic blood pressures. By average 24-hour ambulatory systolic/diastolic blood pressure measurements, the decreases produced were 0.0/0.2 mm Hg for placebo and 9.2/6.9, 9.9/6.4, and 13.2/8.5 mm Hg, respectively, for losartan, 50 mg once daily, 100 mg once daily, and 50 mg twice daily. All drug effects were different from placebo (P < .01). The effects of losartan, 50 mg twice daily, were not significantly different from those of losartan, 100 mg once daily, but, as expected, the effects were greater than those of losartan, 50 mg once daily (P < .05). Addition of hydrochlorothiazide, 12.5 mg/d, during an additional 2-week treatment period in patients whose clinical diastolic blood pressure remained at 85 mm Hg or higher while receiving monotherapy produced additional and clinically meaningful blood pressure decrements that were similar in all four treatment groups. There was no clinically important difference in the incidence of adverse events among the losartan-treated and placebo groups [corrected]. CONCLUSION: Ambulatory blood pressure monitoring, which virtually eliminated antihypertensive placebo responses, demonstrated clear 24-hour efficacy for losartan, 50 mg once daily, as well as for higher doses of 100 mg once daily and 50 mg twice daily. This AT1 receptor blocker had antihypertensive effects that appeared additive when combined with low-dose diuretic therapy. Losartan was generally well tolerated.

A randomized, placebo-controlled, double-blind, parallel study of various doses of losartan potassium compared with enalapril maleate in patients with essential hypertension.

The efficacy and safety of various doses of losartan potassium, a specific and selective angiotensin II receptor antagonist, were compared with those of placebo and enalapril maleate 20 mg in patients with mild to moderate essential hypertension in a randomized, double-blind, parallel study. We randomly allocated 576 patients at the end of a 4-week placebo baseline period to 8 weeks of once-daily double-blind treatment with losartan potassium 10, 25, 50, 100, or 150 mg, enalapril maleate 20 mg, or placebo. After 8 weeks of treatment, mean reductions from baseline in supine systolic/diastolic pressure 24 hours after dosing (trough) for losartan potassium 10, 25, 50, 100, and 150 mg, enalapril maleate 20 mg, and placebo were 7.6/7.9, 7.8/6.8, 13.0/10.1, 8.9/9.9, 10.5/9.7, 14.7/11.2, and 3.8/5.6 mm Hg, respectively. Compared with mean changes in supine diastolic pressure in the placebo group, losartan potassium 50 to 150 mg and enalapril maleate 20 mg produced clinically important and statistically significant reductions (P < or = .01) in blood pressure. At 24 hours after dosing, the blood pressure changes obtained with losartan potassium 50 mg were essentially identical to those obtained with enalapril maleate 20 mg. While there was a dose-related effect with losartan potassium from 10 to 50 mg at peak (6 hours after dosing), doses of 10 and 25 mg were not consistently different from placebo 24 hours after dosing. To assess the once-daily effect of losartan potassium, trough-to-peak ratios of the mean changes in supine diastolic pressure after 8 weeks of treatment were calculated.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of modulators of the renin-angiotensin-aldosterone system on cough. Losartan Cough Study Group.

OBJECTIVE: To compare the incidence of cough in patients with a history of angiotensin converting enzyme (ACE) inhibitor-related cough who received losartan [a type 1 angiotensin II (Ang II) receptor antagonist], lisinopril (an ACE inhibitor) or hydrochlorothiazide (a diuretic). DESIGN: An international, multicentre, randomized double-blind, parallel-group controlled trial. SETTING: Outpatient clinics at 20 tertiary care medical centres in 11 countries. PATIENTS: One hundred and thirty-five patients with uncomplicated primary hypertension with a history of ACE inhibitor-related cough were randomly assigned to the double-blind treatment phase and completed the study. INTERVENTION: After confirming that the cough was ACE inhibitor-related by a single-blind rechallenge, followed by a placebo washout period, patients were randomly assigned to receive 50mg losartan, 20mg lisinopril or 25mg hydrochlorothiazide once a day for 8 weeks. MAIN OUTCOME MEASURES: Cough incidence, severity and frequency were assessed by a self-administered questionnaire and a visual analogue scale. RESULTS: The percentage of patients who complained of cough was significantly higher with lisinopril than with losartan or hydrochlorothiazide. The mean visual analogue scale scores for patients treated with lisinopril demonstrated that these patients coughed more frequently than those who received losartan or hydrochlorothiazide. CONCLUSION: The incidence of cough related to the type 1 Ang II receptor antagonist losartan is significantly lower than that observed with lisinopril, and similar to that observed with hydrochlorothiazide in patients with a rechallenged ACE inhibitor cough. Type 1 Ang II receptor antagonists represent a potential new treatment for hypertensive patients in whom ACE inhibitors are indicated, but who develop a cough with these agents.

Efficacy and safety of losartan/hydrochlorothiazide in patients with severe hypertension.

This 12-week, open-label, multicenter study assessed the efficacy and safety of losartan/hydrochlorothiazide (HCTZ), alone or in combination with other antihypertensive agents, in the treatment of patients with severe systemic hypertension. Treatment began with once-daily losartan/HCTZ 50/12.5 mg. The dose was increased to 100/25 mg, if required, to achieve blood pressure (BP) control (sitting diastolic BP <95 mm Hg); felodipine (extended release) and/or atenolol could be added if target sitting diastolic BP was not achieved with losartan/HCTZ alone. Mean sitting systolic BP of the 131 patients enrolled was 165.3 mm Hg at baseline and 139.8 mm Hg at final visit (reduction -25.4 mm Hg; p < or =0.01). Mean sitting diastolic BP was 111.9 mm Hg at baseline and 93.6 mm Hg at final visit (reduction -18.4 mm Hg; p < or =0.01). After 2 weeks of treatment, 63.8% of patients (83 of 130) were taking losartan/HCTZ 50/12.5 mg alone. By the final visit, one third of patients (35.1%; 46/131) were still only taking losartan/HCTZ. Most patients (48.1%; 63 of 131) were taking losartan/HCTZ 100/25 mg plus felodipine (extended release) at the final visit. Losartan/HCTZ was well tolerated. Drug-related adverse experiences occurred in 30 patients (22.9%). Only 2 patients (1.5%) had a serious adverse experience; 6 patients (4.6%) discontinued the drug because of an adverse experience. In conclusion, losartan/ HCTZ, alone or as part of a regimen with other standard antihypertensive agents, is effective and well tolerated in the treatment of patients with severe hypertension.

Use of losartan in the treatment of hypertensive patients with a history of cough induced by angiotensin-converting enzyme inhibitors.

The objective of this study was to determine the incidence of dry cough in hypertensive patients with a history of angiotensin-converting enzyme (ACE) inhibitor-induced cough after treatment with losartan (an angiotensin II-receptor antagonist), lisinopril (an ACE inhibitor), or placebo. One hundred patients from 16 outpatient treatment centers in the United States were included in this double-masked, randomized, parallel-group, active- and placebo-controlled study, with stratification according to sex. After a challenge phase with lisinopril and a placebo washout phase, patients were randomly allocated to receive losartan 50 mg once daily, lisinopril 20 mg once daily, or placebo for a maximum of 8 weeks. The primary efficacy end point of the study was the presence or absence of dry cough during the double-masked period, as rated by the patient at each visit using a validated symptom assessment questionnaire. A secondary end point was the frequency of dry cough, as measured at each visit using a visual analogue scale (VAS). The incidence of dry cough was significantly higher in the lisinopril group than in the losartan and placebo groups (87.5% vs 36.7% and 31.4%, respectively) at the end of the double-masked treatment period; there was no statistically significant difference between the losartan and placebo groups. Mean VAS scores showed that patients treated with lisinopril rated themselves as having a significantly higher frequency of cough than did patients treated with losartan or placebo (4.0 vs 1.2 and 1.5, respectively). Again, the difference between the losartan and placebo groups was not statistically significant. All treatments were otherwise well tolerated, and no serious clinical or laboratory adverse events were reported during the double-masked phase of the study. These results demonstrate that the incidence, severity, and frequency of dry cough in patients with a history of ACE inhibitor-induced dry cough are significantly lower in those treated with losartan than in those treated with lisinopril and are similar to the incidence, severity, and frequency of dry cough in those receiving placebo.

Randomised, double-blind, parallel study of the anti-hypertensive efficacy and safety of losartan potassium compared with felodipine ER in elderly patients with mild to moderate hypertension.

This study investigated the anti-hypertensive efficacy and tolerability of once-daily losartan potassium (50 mg titrated to 100 mg), an angiotensin II receptor antagonist, compared with once daily felodipine extended release (ER) (5 mg titrated to 10 mg), a calcium channel blocker, after 12 weeks of therapy in elderly hypertensive patients. Following a 4-week, single-blind, placebo baseline period, qualifying patients were randomly allocated to 12 weeks of double-blind treatment with losartan potassium or felodipine ER. After 6 weeks, patients with a 24 h post-dose sitting diastolic blood pressure > or = 90 mm Hg had their dose doubled for the remaining 6 weeks. At 6 weeks, there was a greater BP response for felodipine ER than losartan potassium in elderly patients with mild to moderate hypertension. However, after 12 weeks of therapy, losartan potassium reduced BP as effectively as felodipine ER with no differences in mean BP reduction or anti-hypertensive response category between treatment groups. In this study, both treatments were well tolerated; felodipine ER was associated with a numerically higher incidence of headache and oedema while the incidence of asthenia was numerically higher in losartan-treated patients.

The losartan renal protection study--rationale, study design and baseline characteristics of RENAAL (Reduction of Endpoints in NIDDM with the Angiotensin II Antagonist Losartan).

The RENAAL Study is a double-blind, placebo-controlled trial to evaluate the renal protective effects of losartan in Type 2 diabetic patients with nephropathy. The study has enrolled 1513 patients and is expected to continue for 3.5 years after the last patient has been entered. Eligible patients must have a urinary albumin:creatinine ratio of at least 300 mg/g and serum creatinine between 1.3 to 3.0 mg/dL. Eligible hypertensive or normotensive patients are randomised to receive either losartan or placebo, in addition to their existing antihypertensive therapy. Medications that block angiotensin production or action, are excluded. The primary endpoint is a composite of the time to first event of doubling of serum creatinine, end-stage renal disease, or death; secondary endpoints include cardiovascular events, progression of renal disease, and changes in proteinuria; tertiary endpoints include quality of life, healthcare resource utilisation, and amputations. Patients include Caucasians (48.6%), Blacks (15.2%), Asians (16.7%), and Hispanics (18.2%). Baseline urinary albumin:creatinine ratio and serum creatinine levels average 1867 mg/g and 1.9 mg/dL, respectively. Mean systolic and diastolic blood pressures are 153 and 82 mmHg, respectively. RENAAL will document whether blockade of the AII receptor with losartan produces clinical benefits in patients with Type 2 diabetes and nephropathy.

Ureteral fibropapilloma in a dog.

A fibropapilloma was found to involve the left ureter in a 7-year-old castrated male Doberman Pinscher dog. Severe unilateral hydronephrosis and hydroureter were associated with the ureteral mass. Treatment consisted of unilateral nephrectomy and ureterectomy. This case represents an additional type of primary ureteral neoplasm found in the dog.

Review of the American College of Radiology--National Electrical Manufacturers' Association standards activity.

The American College of Radiology and the National Electrical Manufacturers' Association published the ACR-NEMA Digital Imaging and Communications Standard in 1985. Implementations are just now becoming available. During this time, working groups of the committee responsible for the standard have been very active. An expanded version of the standard was published in 1988 and a third version, to be known as Digital Imaging and Communications in Medicine (DICOM), is being prepared for publication in 1992. This paper briefly reviews the history of the standard, describes recent activities, outlines the extensions planned for the DICOM standard, and describes the participation of the committee in international radiological imaging standards activities.

Association between cough and angiotensin converting enzyme inhibitors versus angiotensin II antagonists: the design of a prospective, controlled study.

BACKGROUND: A common adverse experience in hypertensive patients treated with angiotensin converting enzyme (ACE) inhibitors is a tickling dry cough. OBJECTIVES: The aim of the present study was to review clinical observations and mechanisms of cough associated with ACE inhibitors. In addition, since the AT1-type angiotensin II antagonists (represented by losartan, MK954, DuP753) are not expected to influence other systems (kinins, prostaglandins) affected by ACE inhibitors, we explored the hypothesis that antihypertensive therapy with these agents will not be associated with cough at a similar frequency or quality to that seen with ACE inhibitors. DESIGN AND METHODS: Patients with a history of an ACE inhibitor-associated dry cough confirmed by a second challenge with lisinopril were enrolled into an international, multicenter, randomly allocated, double-blind, parallel-group, controlled trial, to be treated with losartan, lisinopril or hydrochlorothiazide. The presence and severity of cough were assessed by a self-administered questionnaire and a visual analog scale, respectively. CONCLUSIONS: It is expected that the new class of antihypertensive agents, angiotensin II antagonists, will not be associated with the high incidence of dry cough associated with the use of ACE inhibitors. It appears that this cough is not related to alterations in the renin-angiotensin system but to kininase II effects.

Development and persistence of antibody in a high risk institutionalized population given plasma-derived hepatitis B vaccine.

Three hundred and twenty-two (322) persons with severe mental handicaps were given plasma-derived hepatitis B vaccine (20 micrograms dose at 0, 1 and 6 months). Following the third injection, 95% of the vaccinees were positive for anti-HBs, while 92% achieved a protective level of antibody (greater than or equal to 10 mIU ml-1) with a geometric mean titre of 2568 mIU ml-1. Females responded better than males. Antibody responses declined with increasing age in both sexes, but they were not significantly influenced by body weight. Persistence of antibody in responders was followed over 4 years. The proportion of responders maintaining greater than or equal to 10 mIU ml-1 was a function of initial antibody titre but was not significantly affected by sex, age or body weight. Overall, 76% of the responders are estimated to have greater than or equal to 10 mIU ml-1 of anti-HBs 4 years after the first injection of vaccine.

Field test reliability of a new lens opacity rating system utilizing slit-lamp examination.

A field test of a lens opacity rating system was run. Findings were graded in 7 categories: Cortex: (1) Waterclefts, Vacuoles, & Flakes (WVF, 4 grades), (2) Wedges & Spokes graded by number of Quadrants affected (WS-Q), and (3) Inward extent of Wedges & Spokes (WS-I, 3 grades); Nucleus: (4) Opacification (NUC-O) and (5) Coloration (NUC-C), each using 4 grades; and Subcapsular areas: (6) Anterior (SUB-A) and (7) Posterior (SUB-P) opacification, each using 5 grades. An instruction booklet with corresponding guidelines, sketches, and photographs was developed. Reproducibility of grading was tested in 3 clinics using 16 ophthalmologist-examiners. At each clinic, examiners were randomly paired. They independently performed slit-lamp exams of assigned patients (9 on average) on the same day (inter-examiner) and 1-2 weeks later (intra-examiner). To test intra-examiner reliability, examiners were divided into two groups (one from each pair), with gradings analyzed by group. For each group, 53 to 58 patients had evaluable examinations. Intra-examiner concordance for each lens category (defined as at most one grade difference in one lens) was as follows (for examiner groups 1 and 2, resp.): WVF: 98% & 97%; WS-Q: 96% & 100%; WS-I: 100% & 100%; NUC-O: 98% & 100%; NUC-C: 100% & 98%; SUB-A: 90% & 100%; and, SUB-P: 92% & 100%. Inter-examiner concordances were slightly lower than those found for intra-examiner. Grading lens findings in the manner described above appears to have potential utility in large scale studies.

An update on American College of Radiology-National Electrical Manufacturers Association standards activity.

The American College of Radiology-National Electrical Manufacturer's Association (ACR-NEMA) Standard was published 5 years ago. Implementations are just now becoming available in a form other than a prototype. Though this seems like a long interval between the initial work and results, the organization responsible for the standard, the ACR-NEMA Digital Imaging and Communications Standards Committee, has not been idle. Much of the progress which has been made is the result of cooperative work involving industry, the Committee and its Working Groups (WG), and the medical imaging user community. This paper will briefly review the history of the development of what is now a family of ACR-NEMA standards, describe the current activity of the WGs, and indicate in what directions the WGs are headed for both new and updated standards.

The cost-effectiveness of losartan versus captopril in patients with symptomatic heart failure.

The Losartan Heart Failure ELITE Study recently found that in patients with symptomatic heart failure and a left ventricular ejection fraction of /=65 years with symptomatic heart failure. Data on health care resource utilization were collected as part of the trial. We conducted a cost-effectiveness analysis to estimate the lifetime benefits of treatment and the associated costs. We observed no differences between treatments in the number of hospitalizations, hospital days, and emergency room visits per patient over the trial period. We estimated the total cost of losartan to be USD 54 (95% CI: USD -1,717, USD 1,755) less per patient than captopril over this time frame. We also estimated that over the projected remaining lifetime of the study population, losartan compared to captopril would increase survival by 0.20 years (undiscounted) at an average cost of USD 769 (discounted) more per patient. This cost increase translated into a cost-effectiveness ratio of USD 4,047 per year of life gained for losartan relative to captopril. In patients with symptomatic heart failure, losartan compared to captopril increased survival with better tolerability at a cost well within the range accepted as cost-effective.

Randomised trial of losartan versus captopril in patients over 65 with heart failure (Evaluation of Losartan in the Elderly Study, ELITE)

BACKGROUND: To determine whether specific angiotensin II receptor blockade with losartan offers safety and efficacy advantages in the treatment of heart failure over angiotensin-converting-enzyme (ACE) inhibition with captopril, the ELITE study compared losartan with captopril in older heart-failure patients. METHODS: We randomly assigned 722 ACE inhibitor naive patients (aged 65 years or more) with New York Heart Association (NYHA) class II-IV heart failure and ejection fractions of 40% or less to double-blind losartan (n = 352) titrated to 50 mg once daily or captopril (n = 370) titrated to 50 mg three times daily, for 48 weeks. The primary endpoint was the tolerability measure of a persisting increase in serum creatinine of 26.5 mumol/L or more (> or = 0.3 mg/dL) on therapy; the secondary endpoint was the composite of death and/or hospital admission for heart failure; and other efficacy measures were total mortality, admission for heart failure, NYHA class, and admission for myocardial infarction or unstable angina. FINDINGS: The frequency of persisting increases in serum creatinine was the same in both groups (10.5%). Fewer losartan patients discontinued therapy for adverse experiences (12.2% vs 20.8% for captopril, p = 0.002). No losartan-treated patients discontinued due to cough compared with 14 in the captopril group. Death and/or hospital admission for heart failure was recorded in 9.4% of the losartan and 13.2% of the captopril patients (risk reduction 32% [95% CI -4% to + 55%], p = 0.075). This risk reduction was primarily due to a decrease in all-cause mortality (4.8% vs 8.7%; risk reduction 46% [95% CI 5-69%], p = 0.035). Admissions with heart failure were the same in both groups (5.7%), as was improvement in NYHA functional class from baseline. Admission to hospital for any reason was less frequent with losartan than with captopril treatment (22.2% vs 29.7%). INTERPRETATION: In this study of elderly heart-failure patients, treatment with losartan was associated with an unexpected lower mortality than that found with captopril. Although there was no difference in renal dysfunction, losartan was generally better tolerated than captopril and fewer patients discontinued losartan therapy. A further trial, evaluating the effects of losartan and captopril on mortality and morbidity in a larger number of patients with heart failure, is in progress.