Bacteriologic cure of experimental Pseudomonas keratitis. (1/1937)

Two long-term therapy trials with high concentrations of antibiotic were carried out to determine the duration of therapy required to achieve bacteriologic cure of experimental Pseudomonas keratitis in guinea pigs. In the first study, corneas still contained Pseudomonas after 4 days of continual topical therapy with either tobramycin 400 mg/ml, amikacin 250 mg/ml, ticarcillin 400 mg/ml, or carbenicillin 400 mg/ml. In an 11-day trial of topical therapy with tobramycin 20 mg/ml, 34 of 36 corneas grew no Pseudomonas after 6 or more days of therapy. The bacteriologic response to therapy in this model occurred in two phases. About 99.9% or more of the organisms in the cornea were killed in the first 24 hr of therapy. The numbers of bacteria remaining in the cornea declined gradually over the next several days until the corneas were sterile. Optimal antibiotic therapy may include two stages: initial intensive therapy with high concentrations of antibiotic applied frequently to achieve a large rapid decrease in numbers of organisms in the cornea, followed by prolonged, less intensive therapy to eradicate organisms and prevent relapse.  (+info)

A tale of two (or more) cities: geographic transferability of pharmacoeconomic data. (2/1937)

The economic evaluation of a new medicine often must be based on data gathered in multiple countries. Because replication of trials is an expensive and inefficient undertaking, analysts need to determine the validity of transferring cost-effectiveness data from one country to another. Threats to transferring data involve differences among countries with regard to demography and epidemiology of disease, clinical practice and conventions, incentives to and regulation of healthcare providers, relative price levels, consumer preferences, and opportunity cost of resources. Because of these differences, a drug can be cost-effective in one country and not cost-effective in another. Adapting a cost-effectiveness study conducted in one country to another country requires careful scrutiny of the relevance of comparators, practice patterns, and relative price weights.  (+info)

Use of an intravenous contrast agent (Optison) to enhance echocardiography: efficacy and cost implications. Optison Multicenter Study Group. (3/1937)

OBJECTIVE: To compare the overall diagnostic costs associated with non-contrast and contrast echocardiography. STUDY DESIGN: Phase III clinical trial. PATIENTS AND METHODS: In a secondary analysis of data from a phase III clinical trial of the intravenous contrast agent Optison, we compared the costs associated with obtaining a diagnosis in 203 patients who underwent non-contrast and contrast echocardiography. Costs for the initial test and any follow-up tests were derived from adjusted Medicare charges and a transition-1 microcost accounting system. RESULTS: Diagnostic yield from echocardiograms was 87% with the use of Optison (3 mL) and 49% when no contrast agent was used (P < 0.001). Because technically inadequate echocardiograms were more common in the non-contrast group, follow-up testing was recommended for 42% of patients in this group compared with 12% of those who had undergone a contrast-enhanced echocardiogram (P < 0.001). Although use of Optison increased the initial diagnostic cost by $125, overall costs were 17% lower when Optison was used (P < 0.0001). Use of Optison also resulted in a 17% to 70% decrease in confirmatory transesophageal echocardiography, catheterization, and nuclear studies. Optison improved diagnostic accuracy by 2.7-fold in patients with an initial non-diagnostic echocardiogram, resulting in a substantial cost savings of $269 per patient.  (+info)

Clinical trial experience by simulation: a workshop report. (4/1937)

A new computer program for experimental design simulation was used in a three-day postgraduate workshop on clinical trials. Participants were given information on a fictitious new drug and asked to design a trial to evaluate it. On the first day they reviewed the data and designed a protocol, and results for these specifications were generated on the computer. The second day was spent analysing results, and on the last day the findings of the different studies were presented at a symposium. Flexibility of the program ensured a high degree of realism in all trials and emphasised the influence of design on results and conclusions.  (+info)

Research strategies for behavioral teratology studies. (5/1937)

Several compelling aruguments have been advanced in support of expanding the use of "behavioral teratology" evaluations as routine components of toxicologic screening procedures. As a basis for development of effective behavioral teratology screening approaches, a conceptual framework is presented which interrelates: (1) changes in relative functional brain capacity with age, (2) possible times and durations of exposures to environmental insults, and (3) various types of toxicity testing procedures carried out at appropriate time points in relation to different exposure period. Within the context, several research strategies for behavioral teratology studies are concisely posed and evaluated. These include: (1) clinical hypothesis testing, where particular effect(s) of a given agent are evaluated based on hypotheses derived from clinical or epidemiological observations; (2) comprehensive screening approaches, where multifaceted, long-term longitudinal neurobehavioral evaluations are employed to assess whether any of a large number of possible deletarious effects are exerted by an agent and at what threshold exposure levels; (3) alternative screening heuristics, by which adequate assessments of neurobehavioral toxicity of various agents may be accomplished without completion of more exhaustive, but also more expensive and time-consuming comprehensive screening protocols.  (+info)

Randomized double-blind placebo-controlled trial of homoeopathic 'proving' for Belladonna C30. (6/1937)

Homoeopathic drug pictures are developed by recording the symptomatic effects of homoeopathic remedies given to healthy volunteers (a 'proving'). In a double-blind randomized controlled trial we tested the hypothesis that individuals using an infinitesimal dilution of Belladonna (thirtieth potency, C30) would record more true symptoms, on a questionnaire that contained both true and false Belladonna proving symptoms, than those receiving placebo. 60 volunteers entered the study and 47 completed data collection. We were unable to distinguish between Belladonna C30 and placebo using our primary outcome measure. For the secondary outcome measure we analysed the number of individuals who proved to the remedy according to our predefined criteria: 4 out of 19 proved in the Belladonna C30 group and 1 out of 27 in the placebo group (difference not statistically significant). This pilot study does not demonstrate a clear proving reaction for Belladonna C30 versus placebo, but indicates how the question might be further investigated.  (+info)

Cutaneously applied 4-hydroxytamoxifen is not carcinogenic in female rats. (7/1937)

Tamoxifen is widely used to treat oestrogen-dependent carcinoma of the breast. Previous long-term studies have shown that oral administration of tamoxifen induces hepatoproliferative lesions and hepatocellular tumours in rats. 4-hydroxytamoxifen is an active metabolite of tamoxifen undergoing clinical evaluation for the treatment of various non-malignant breast diseases by topical application. In the present study, 4-hydroxytamoxifen was administered daily by cutaneous application for 101 weeks to groups of 50 female Sprague-Dawley rats at 20, 140 or 1000 microg/kg/day. The product was applied with no occlusive bandage and oral ingestion was avoided by application of an Elizabethan collar for 6 h after administration. Treatment with 4-hydroxytamoxifen was clinically well tolerated and induced changes such as decreased food consumption and body weight gain, uterine and ovarian atrophy, mucification of vaginal epithelium and reduced mammary development, all of which were attributed to its pharmacological action. Mortality was significantly lower in the treated animals. The number of animals with palpable masses was similarly reduced. The incidence of mammary tumours and hypophyseal tumours was markedly lower in 4-hydroxytamoxifen-treated animals. The incidence of chronic tubulo-interstitial nephropathies, a common cause of mortality, was also lowered. There was no evidence of a carcinogenic action of 4-hydroxytamoxifen on the liver, genital organs or skin. Plasma levels of 4-hydroxytamoxifen were stable over the duration of the study and were proportional to the administered dose, exceeding clinical plasma levels by 60-fold at the high dose-level. In conclusion, 4-hydroxytamoxifen is not carcinogenic in the rat and reduces the incidence of spontaneous mammary and hypophyseal tumours.  (+info)

Evaluation of the renal effects of an antisense phosphorothioate oligodeoxynucleotide in monkeys. (8/1937)

Antisense phosphorothioate oligodeoxynucleotides are therapeutic agents that provide target specificity resulting from Watson-Crick base pairing. However, there are nonspecific effects that in some instances result in toxicity. These compounds accumulate in the kidney and induce renal proximal tubular degeneration at high doses. The relationship between accumulation of phosphorothioate oligodeoxynucleotides in the kidney, indicators of renal toxicity, and histomorphology were investigated in rhesus monkeys. Monkeys received vehicle or an escalating dose regimen of 3, 10, 40, and 80 mg/kg of ISIS 2105 and were then evaluated for changes in clinical pathology indices, urinalysis parameters, and renal histopathology. Urinalysis revealed an increase in protein levels and a slight increase in blood content following the third 40 mg/kg dose and continuing through the 80 mg/kg doses, whereas other urinary markers of renal toxicity were unchanged. Creatinine clearance was slightly decreased in monkeys during the 80 mg/kg dose cycle. Granulation in the cytoplasm of proximal tubular epithelial cells was evident by microscopic examination of kidney and was present at all doses examined and increased with dose. Immunohistochemical staining localized the oligodeoxynucleotide within these granules. Histopathologic changes consisting of minimal to moderate tubular degeneration were present only at the higher doses of 40 and 80 mg/kg and at high tissue concentrations, and these changes occurred concurrent with functional alterations, whereas lower doses (< or = 10 mg/kg) did not affect a pathologic or functional change.  (+info)

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