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Results for “efficacy determination”

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At least 73 records · Page 4Linked to original sources
PubMed1997

Efficacy of eprinomectin against mange mites in cattle.

OBJECTIVE: To determine whether eprinomectin was effective against mange caused by Chorioptes bovis and Sarcoptes bovis in cattle. ANIMALS: 80 cows naturally infested with C bovis and 30 cattle experimentally infested with S bovis. PROCEDURE: 6 trials were performed to determine efficacy against C bovis, and 2 trials were performed to determine efficacy against S bovis. In each trial, a group of untreated animals or of animals treated with vehicle alone was compared with a group of animals treated with a 0.5% formulation of eprinomectin applied topically (500 micrograms/kg). Number of mites in skin scrapings was determined prior to treatment and at weekly intervals for 8 weeks after treatment. Severity of skin lesions was evaluated when skin scrapings were obtained. In 5 trials, animals were weighed before and 56 days after treatment. RESULTS: Mite counts for treated cattle were significantly less than counts for control cattle from day 14 onwards in trials to determine efficacy against C bovis and from day 7 onwards in trials to determine efficacy against S bovis. Mites were not detected in scrapings collected from treated cattle on day 56. Mean weight gain of treated cattle was not significantly different from mean weight gain of control cattle in trials evaluating efficacy against C bovis but was significantly greater in trials evaluating efficacy against S bovis. CONCLUSION AND CLINICAL RELEVANCE: Eprinomectin was highly effective against C bovis and S bovis. Because eprinomectin can be administered to lactating cows, it may be useful for controlling mange in cattle.

Administration, Topical↗
PubMed2003

Factors determining the efficacy of alpha-helical antimicrobial peptides.

A database of alpha-helical antimicrobial peptides (AMP) was established and their minimum inhibitory concentrations (MIC) were compared with their physiochemical characteristics in an attempt to establish those features that determine efficacy. There is no significant difference in AMP sensitivity between Gram-positive and Gram-negative bacteria but fungi did require higher concentrations to achieve the same degree of growth inhibition. For antibacterial peptides there appears to be a positive correlation between MIC and hydrophobic arc size and a negative correlation between MIC and net charge.

Animals↗
PubMed2005

A single-blinded randomised controlled study to determine the efficacy of Omnilux Revive facial treatment in skin rejuvenation.

To determine the efficacy of Omnilux Revive facial treatment in skin rejuvenation, twenty-three volunteers received randomised 20 min treatments three times a week for three weeks to one half of their face, with the untreated side acting as control. Regular assessments were carried out, focusing on parameters of subject satisfaction, photographic assessments, skin elasticity (Cutometer) and skin hydration (Corneometer CM825). Ninety-one percent of the volunteers reported visible changes to their skin. Blinded photographic evaluation reported a clinical response in 59% of the subjects. Objective analysis failed to show statistically significant changes in skin hydration or elasticity. The Omnilux Revive LED lamp is a safe alternative non-ablative skin rejuvenation treatment.

Adult↗
PubMed1999

Treatment protocol determines the efficacy of clindamycin in acute murine toxoplasmosis.

To determine the contribution to the efficacy of clindamycin in acute murine toxoplasmosis of treatment protocol variables, groups of Swiss Webster mice inoculated intraperitoneally with 10(2) RH strain Toxoplasma gondii tachyzoites were treated with peroral clindamycin at 25, 50 and 400 mg/kgBM per day for 1, 2 and 3 weeks. While the lowest drug dose applied for a single week prolonged survival time as compared to untreated animals, not even the highest dose applied for 1 or 2 weeks completely prevented mortality. Conversely, 100% protection was achieved with 3-week treatment courses at both 50 and 400 mg/kg per day. While both survival rates and survival times increased in parallel with the drug dose and treatment duration, the latter was shown to be critical to the outcome, suggesting the use of clindamycin as an antitoxoplasmic agent should be as a prolonged course.

Acute Disease↗
PubMed2000

Prospective randomized two-Arm controlled study to determine the efficacy of a specific intervention to improve long-term adherence to highly active antiretroviral therapy.

BACKGROUND: Nearly perfect compliance seems to be indispensable to obtain the maximum benefit from highly active antiretroviral therapy (HAART). Interventions to ensure a high level of adherence during a relatively long-term period of therapy are necessary. METHODS: This is a prospective, randomized, two-arm controlled study including patients starting their first-or second-line HAART who were randomized to receive psychoeducative intervention to implement adherence (experimental group [EG]) or a usual medical follow-up (control group [CG]). We aimed to study the efficacy of a psychoeducative intervention to ensure long-term adherence to HAART, its relation with the virologic efficacy of treatment, and to determine the variables related to long-term adherence. Visits were made at weeks 0, 4, 24, and 48 for data collection. Self-reported adherence was registered at each visit and its veracity was tested by randomized blood analyses performed without previous warning to 40% of patients. Appropriate adherence was defined as the consumption of >/=95% of medication prescribed. Statistical analyses were performed both by the as treated (AT) and the intention to treat missing = failure (ITT) methods. RESULTS: In all, 116 patients were included. At week 48, 94% of patients in the EG versus 69% controls achieved adherence >/=95% (p =.008); 89% of patients in the EG versus 66% controls had HIV-1 RNA levels <400 copies/ml (p =.026). Overall, 85% of patients with adherence >/=95% but only 45% of those with adherence <95% had viral load (VL) <400 copies/ml (p =. 008). In multivariate analysis, variables significantly related to adherence were having received a psychoeducative intervention (odds ratio [OR], 6.58; p =.04), poor effort to take medication (OR, 5.38; p =.03), and high self-perceived capacity to follow the regimen (OR, 13.76; p =.04). Self-reported adherence and drug plasma levels coincided in 93% of cases. However, differences in adherence did not reach statistical significance in the ITT analysis although a clear tendency toward benefit was observed in EG. CONCLUSIONS: Specific and maintained psychoeducative interventions based on excellence on clinical practice are useful to keep high levels of adherence as well as high levels of viral suppression. There is a clear relation between high adherence levels and virologic success. Assessment of certain specific variables related to adherence may be helpful to monitor patient's compliance in the clinical setting.

Adult↗
PubMed2006

Oral vaccination of brushtail possums with BCG: Investigation into factors that may influence vaccine efficacy and determination of duration of protection.

AIMS: To determine factors that may influence the efficacy of an oral pelleted vaccine containing Mycobacterium bovis bacille Calmette-Guérin (BCG) to induce protection of brushtail possums against tuberculosis. To determine the duration of protective immunity following oral administration of BCG. METHODS: In Study 1, a group of possums (n=7) was immunised by feeding 10 pellets containing dead Pasteur BCG, followed 15 weeks later with a single pellet of live Pasteur BCG. At that time, four other groups of possums (n=7 per group) were given a single pellet of live Pasteur BCG orally, a single pellet of live Danish BCG orally, 10 pellets of live Pasteur BCG orally, or a subcutaneous injection of live Pasteur BCG. For the oral pelleted vaccines, BCG was formulated into a lipid matrix, and each pellet contained approximately 107 colony forming units (cfu) of BCG, while the vaccine injected subcutaneously contained 106 cfu of BCG. A sixth, non-vaccinated, group (n=7) served as a control. All possums were challenged by the aerosol route with a low dose of virulent M. bovis 7 weeks after vaccination, and killed 7-8 weeks after challenge. Protection against challenge with M. bovis was assessed from pathological and bacteriological findings. In Study 2, lipid-formulated live Danish BCG was administered orally to three groups of possums (10-11 per group), and these possums were challenged with virulent M. bovis 8, 29 or 54 weeks later. The possums were killed 7 weeks after challenge, to assess protection in comparison to a non-vaccinated group. RESULTS: The results from Study 1 showed that vaccine efficacy was not adversely affected by feeding dead BCG prior to live BCG. Feeding 10 vaccine pellets induced a level of protection similar to feeding a single pellet. Protection was similar when feeding possums a single pellet containing the Pasteur or Danish strains of BCG. All vaccinated groups had significantly reduced pathological changes or bacterial counts when compared to the non-vaccinated group. In Study 2, oral administration of Danish BCG induced protection against challenge with M. bovis, which persisted for at least 54 weeks after vaccination. Some protection was observed in possums challenged 54 weeks after vaccination, but this protection was significantly less than that observed in groups vaccinated 29 or 8 weeks prior to challenge. There was a strong relationship between the proportion of animals producing positive lymphocyte proliferation responses to M. bovis antigens and protection against challenge with M. bovis. CONCLUSIONS: Factors considered potentially capable of interfering with vaccination, including feeding dead BCG to possums prior to feeding live BCG, feeding multiple doses of BCG at one time, and changing strains of BCG, were shown not to interfere with the acquisition of protective immune responses in possums. Protection against tuberculosis was undiminished up to 29 weeks after vaccination with BCG administered orally. It is concluded that vaccination of possums by feeding pellets containing BCG is a robust and efficient approach to enhance the resistance of these animals to tuberculosis.

Administration, Oral↗
PubMed2004

Test models to determine cleaning efficacy with different types of bioburden and its clinical correlation.

The importance of cleaning as a first crucial step in reprocessing instruments and endoscopes is recognized worldwide. However, no standards to determine the efficacy of cleaning have been established. We have therefore investigated Bodedex forte, a new cleaner, in various test models derived from critical types of bioburden on flexible endoscopes. Removal of dried blood from metal carriers was determined in comparison with standard instrument disinfectants. Removal of biofilm endotoxin from silicone test pieces and removal of dried X-ray contrast medium from polyethylene pieces was measured in comparison with one other standard cleaner. Residual bacteria in a biopsy channel from duodenoscopes following use of Bodedex forte, compared with two other cleaners, were measured in an endoscopy unit. After 15 min exposure to Bodedex forte, 95% of the dried blood were removed. Removal was between 0 and 86% with the disinfectants. Bodedex forte reduced endotoxin by 1.91+0.19 log(10)-steps compared with 0.43+0.19 log(10)-steps Cidezyme (P < 0.001) two-sided t-test). Removal of dried X-ray contrast medium was 99% with Bodedex forte and 94% with a conventional cleaner. No bacterial contamination after reprocessing was found in 98% of duodenoscopes with Bodedex forte (78 duodenoscopes), in 72% with a conventional cleaner (129 duodenoscopes) and in 69% with an enzymatic cleaner (100 duodenoscopes). The difference between the three cleaners was significant (P < 0.001) chi-squared test). The superiority of the cleaning capacity of the new cleaner was demonstrated in various test models, which were designed according to the clinical relevance of different bioburdens. Implementation of accepted and reproducible standards for testing the cleaning efficacy will remain a goal for the next years.

Biofilms↗
PubMed2005

Intracervical application of the nitric oxide donor isosorbide dinitrate for induction of cervical ripening: a randomised controlled trial to determine clinical efficacy and safety prior to first trimester surgical evacuation of retained products of conception.

OBJECTIVE: To determine the therapeutic efficacy and safety of a nitric oxide (NO) isosorbide dinitrate donor to induce cervical ripening of women with missed abortions before surgical evacuation of the uterus. DESIGN: A prospective, randomised, double-blind controlled trial. SETTING: Tertiary referral maternity teaching hospital. Population Sixty women with missed abortions and no cervical dilation. METHODS: Women requesting surgical evacuation of the uterus were randomly selected to receive endocervical 80 mg/1.5 mL isosorbide dinitrate gel solution (n= 30) or 400 mug/1.5 mL misoprostol gel solution (n= 30) every 3 hours to a maximum of four doses or until reaching cervical ripening. Vital signs and symptoms were recorded at baseline and then every 3 hours until finishing therapy. Adverse events, such as headache, abdominal pain, pelvic pain, backache, nausea and vomiting, were evaluated. MAIN OUTCOME MEASURES: Probability of reaching cervical ripening >8 mm Hegar dilator; evaluated at 3, 6, 9 and 12 hours after application of isosorbide dinitrate or misoprostol. RESULTS: The probabilities of induction of cervical ripening by isosorbide dinitrate and misoprostol after four repeated doses at 3-hour intervals were significantly different (P<0.001). Efficacy of therapy after 12 hours was 97% for the isosorbide dinitrate group and 70% for the misoprostol group. Systolic and diastolic blood pressures were lower after administration of isosorbide dinitrate than prostaglandin analogues. The difference in the mean systolic and diastolic blood pressure between treatment groups was greatest at 3 hours, with a difference of 7.7 mmHg (P<0.001) and 5.9 mmHg (P<0.003), respectively. The most frequent side effect associated with isosorbide dinitrate administration was headache, which occurred in 18 out of 30 patients, compared with only 5 out of 30 women in the misoprostol group [relative risk (RR) 2.41, 95% confidence interval (CI) 1.45-4.03, P<0.001). Women treated with misoprostol reported mainly pelvic pain (RR 3.24, 95% CI 1.99-5.27, P<0.001). CONCLUSIONS: Intracervical administration of 80 mg isosorbide dinitrate in women with missed abortions appears to be effective for cervical ripening prior to surgical evacuation of the uterus. Differences in the incidence of non-serious adverse events are not likely to be clinically significant.

Abortion, Induced↗
PubMedDate not supplied

[Metabolic determinants of efficacy of infrared laser therapy in hypertensive patients with combined pathology].

By a distinct pathogenetic direction of a therapeutic action of laser therapy (LT) on different regulators of blood pressure (BP) and metabolism, 109 patients with essential hypertension (EH) and atherosclerosis and/or diabetes mellitus were studied for LT efficacy depending on metabolis disorders. LT demonstrated metabolic neutrality and unefficacy in patients with multiple marked disorders of fat metabolism and hyperglycemia. Metabolic factors determining LT efficacy comprise hypercholesterinemia, hypertriglyceridemia and hyperglycemia. The factorial analysis points to essential factor restructuring in metabolic disorders. The obtained equation of multiple regression allows prognostication of the degree of a fall of mean BP in response to LT depending on the degree of metabolic disorders.

Adult↗
PubMed1999

A randomized, double-blind, placebo-controlled field trial to determine the efficacy and safety of Malarone (atovaquone/proguanil) for the prophylaxis of malaria in Zambia.

Malaria poses a major health risk to people who are exposed to infection in malaria-endemic areas. A randomized, double-blind, placebo-controlled study was conducted to determine the efficacy and safety of Malarone (250 mg of atovaquone/100 mg of proguanil hydrochloride per tablet) for the chemoprophylaxis of Plasmodium falciparum malaria in Zambia. Adult volunteers received a three-day treatment course of Malarone to eliminate pre-existing parasitemia and were then immediately randomized to treatment with either one Malarone tablet daily (n = 136), or one placebo tablet daily (n = 138) for at least 10 weeks. Malaria blood smears were prepared on a weekly basis and a failure of chemoprophylaxis was defined as any subject who had a positive blood smear, or who withdrew from the study due to a treatment-related adverse event. The prophylaxis success rates in the Malarone and placebo groups were 98% and 63%, respectively (P < 0.001). The most commonly reported adverse events with at least a possible causal relationship to study medication were headache and abdominal pain, which occurred with a higher incidence in the placebo group. No subjects were withdrawn from the study due to a treatment-related adverse event. Thus, Malarone appears to have an excellent safety and efficacy profile for the chemoprophylaxis of P. falciparum infection.

Adolescent↗
PubMed2004

Determining the efficacy of resiliency training in the work site.

Resilience and resiliency training, an approach that encompasses the complementary and alternative medicine movement, seems to be an important concept and philosophy that can be embraced by allied health professionals. The purpose of this study was to determine the efficacy of a worksite resiliency training program (personal resilience and resilient relationships [PRRR]) by evaluating its impact on innate resilience/reintegration, selected resilient qualities (self-esteem, locus of control, purpose in life, and interpersonal relations), and job satisfaction. The experimental group received the PRRR training, and the control group did not receive any training. The PRRR training comprised five 8-hour training modules. The study was implemented at a large government organization's facility in Northern Utah. A total of 232 participants were assigned randomly by work unit into the PRRR training group (n = 123) and the control group (n = 109); 150 participants (73 in the experimental and 77 in the control group) were present at all three data collections and were eligible for analysis. Significant and positive change occurred in the experimental group, based on combined survey data, with regard to five of the six variables, with job satisfaction being the only variable not showing positive change in this group. The control group saw no positive effects. The results of the study support the efficacy of the PRRR training as implemented in the work site.

Adaptation, Psychological↗
PubMed2005

Host, viral, and vaccine factors that determine protective efficacy induced by rotavirus and virus-like particles (VLPs).

Critical factors that are important in protection from rotavirus infection have remained elusive. We demonstrate here that inbred mice (C57BL/6 and BALB/c) exhibit differences in: (1) susceptibility to and (2) VLP-induced protection from rotavirus infection. Comparing protection induced by 2/4/6/7-VLPs with inactivated and live rotavirus, intranasally induced protection was dependent on dsRNA or minor structural proteins and correlated with intestinal antibody, while orally induced protection required immunization with replicating virus. Combination oral/intranasal vaccination did not improve VLP protective efficacy. These studies indicate that host, viral, and vaccine factors determine the level of protective efficacy induced by VLPs.

Administration, Intranasal↗
PubMed2004

A multicentre study to determine the efficacy and patient acceptability of the Paxman Scalp Cooler to prevent hair loss in patients receiving chemotherapy.

Alopecia is a distressing and common side-effect of chemotherapy, especially anthracycline- and taxane-containing regimen. A series of studies and reviews have considered scalp cooling as a means of reducing this side-effect without a definitive result. The aim of the study was to determine the efficacy and patient acceptability of scalp cooling using the Paxman Scalp Cooler. This was an open, non-randomised, observational study conducted at eight sites involving 94 patients. Alopecia was assessed using the World Health Organisation (WHO) grading system. Patient acceptability was assessed by questionnaire. Results were compiled by Scalp Cooling Assessment Groups using data from eight centres in the UK collected between 1997 and 2000. Use of the Paxman Scalp Cooler was adjudged a success for 89% of all patients using the WHO grading system for alopecia and for 87% of patients being specifically administered the commonly used 5-fluorouracil, epirubicin and cyclophosphamide (FEC) regimen. When asked about degrees of comfort during the scalp-cooling process, 85% of patients described it as very comfortable, reasonably comfortable or comfortable, with only 15% of patients reporting a description of uncomfortable or very uncomfortable. Scalp cooling using the Paxman Scalp Cooler was found to be an effective technique with minimal side-effects for patients treated with commonly prescribed alopecia-inducing chemotherapy drugs.

Adult↗
PubMed2000

Determination of efficacy of linotroban by inducing a reduction of renal inulin/para-aminohippuric acid clearances with the thromboxane A2 mimetic U-46619 in the conscious female rat.

Linotroban (CAS 141443-73-4), a potent and selective thromboxane (TXA2) receptor antagonist, is known as a novel antithrombotic agent. It is suggested that pharmacological inhibition of TXA2 synthesis or action merits continued evaluation in the treatment of a variety of renal diseases. The aim of this study was the determination of efficacy of this new TXA2 receptor antagonist by assessing its effect on the reduction in inulin and para-aminohippuric acid (PAH) clearances induced by the TX/prostaglandin endoperoxide mimetic U-46619 in the conscious female rats. The following doses (3, 10, 30 mg/kg/24 h) of linotroban mixed with 720 micrograms TX-mimetic U-46619/kg/24 h were administered via osmotic pumps at a delivery rate of 10 microliters/h, implanted s.c. during 72 h. Rats of the U-46619 group were administered 720 micrograms U-46619/kg/24 h alone as described above, controls received 3.5% NaHCO3, respectively. Inulin/PAH clearances were determined at the end of the 4-h clearance period (68 h-72 h). Summarizing the data, glomerular filtration rate (GFR) and PAH clearances were reduced significantly by U-46619. When linotroban (3, 10 or 30 mg/kg/24 h) was added to U-46619 the GFR and PAH clearance were reversed to values that showed no significant differences to the controls.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗
PubMed1997

Does tumour uptake of Foscan determine PDT efficacy?

Preferential retention of photosensitizers in tumours has always been one of the major goals in the search for new photosensitizers and has determined the design of clinical trials with respect to the interval between drug administration and illumination. The purpose of this study was to investigate the importance of tumour and plasma concentrations of Foscan (mTHPC, meta-tetrahydroxyphenylchlorin) in relation to PDT effect. Both pharmacokinetic and tumour response studies were carried out in mice bearing s.c. RIF1 tumours. mTHPC was injected in 1 or 2 doses of 0.3 mg x kg-1. For distribution studies, 14C-labelled mTHPC was given 5 min to 48 hr before determination of plasma and tumour drug levels. Non-labelled sensitizer was used to determine the PDT efficacy for illumination at 5 min to 48 hr after drug administration. PDT efficacy was greatest for illumination at 1 to 3 hr, and for an interval of 48 hr there was no significant tumour-growth delay. In contrast, mTHPC tumour drug levels reached a maximum 6 hr after injection and remained high for 48 hr. A comparison of pharmacokinetics and response studies revealed no significant correlation between tumour mTHPC levels and tumour response. There was, however, a significant correlation between plasma drug levels and tumour response for time intervals of 1 to 48 hr. This association may imply that PDT protocols should use shorter drug-light intervals in combination with lower drug doses. This would increase safety and decrease the extent and duration of normal tissue photosensitization.

Animals↗
PubMed1994

A single amino acid of the human gamma-aminobutyric acid type A receptor gamma 2 subunit determines benzodiazepine efficacy.

Incorporation of the gamma 2 subunit into gamma-aminobutyric acid type A (GABAA) receptors is required for the expression of benzodiazepine pharmacology, but the regions of the subunit responsible for benzodiazepine actions have not been defined. Using mutagenesis, we identified a single amino acid of the gamma 2 subunit of the human GABAA receptor that profoundly alters the nature of this pharmacology. When threonine 142 was mutated to serine, the benzodiazepine receptor antagonist, flumazenil, and the weak inverse agonist, Ro 15-4513, both acted as potent partial agonists. Further, potentiation of GABA responses by diazepam, alprazolam, clonazepam, or flunitrazepam doubled in receptors containing the Ser-142 gamma 2 subunit. In contrast, responses to the Type I benzodiazepine receptor selective ligands, zolpidem, alpidem, and CL218,872, were roughly halved. This change in pharmacology appears to occur at a stage following ligand binding, i.e. the mutation affects benzodiazepine efficacy. There was no effect on GABA affinity or efficacy or pentobarbital, Ro 5-4864, or alphaxalone modulation of GABA responses. These findings demonstrate that very minor changes in receptor structure can profoundly affect the efficacy of receptor ligands. Thus, agonism is determined not only by the structure of the drug, but also by the structure of the receptor, or protein complex, with which it interacts.

Animals↗
PubMed2004

Structural determinants of efficacy at A3 adenosine receptors: modification of the ribose moiety.

We have found previously that structural features of adenosine derivatives, particularly at the N6- and 2-positions of adenine, determine the intrinsic efficacy as A3 adenosine receptor (AR) agonists. Here, we have probed this phenomenon with respect to the ribose moiety using a series of ribose-modified adenosine derivatives, examining binding affinity and activation of the human A3 AR expressed in CHO cells. Both 2'- and 3'-hydroxyl groups in the ribose moiety contribute to A3 AR binding and activation, with 2'-OH being more essential. Thus, the 2'-fluoro substitution eliminated both binding and activation, while a 3'-fluoro substitution led to only a partial reduction of potency and efficacy at the A3 AR. A 5'-uronamide group, known to restore full efficacy in other derivatives, failed to fully overcome the diminished efficacy of 3'-fluoro derivatives. The 4'-thio substitution, which generally enhanced A3 AR potency and selectivity, resulted in 5'-CH2OH analogues (10 and 12) which were partial agonists of the A3 AR. Interestingly, the shifting of the N6-(3-iodobenzyl)adenine moiety from the 1'- to 4'-position had a minor influence on A3 AR selectivity, but transformed 15 into a potent antagonist (16) (Ki = 4.3 nM). Compound 16 antagonized human A3 AR agonist-induced inhibition of cyclic AMP with a K(B) value of 3.0 nM. A novel apio analogue (20) of neplanocin A, was a full A3 AR agonist. The affinities of selected, novel analogues at rat ARs were examined, revealing species differences. In summary, critical structural determinants for human A3 AR activation have been identified, which should prove useful for further understanding the mechanism of receptor activation and development of more potent and selective full agonists, partial agonists and antagonists for A3 ARs.

Adenosine↗
PubMed1998

Hemodynamic changes determine the efficacy of thrombolysis: results from an in-vitro flow model.

BACKGROUND: The efficacy of thrombolytic therapy might be influenced by changes in the hemodynamic status. The aim of the study was to examine whether changes in perfusion pressure could affect the time to reflow in an in-vitro model. METHODS: The in-vitro flow system comprised flexible plastic tubes that enclosed a blood clot formed in one of the circuit arms. Streptokinase (125,000 U) or saline (control) was injected from a proximal side branch to induce thrombolysis. The protocol comprised four treatments: A, perfusion pressure 150/90 mmHg with streptokinase infusion; B, perfusion pressure 150/90 mmHg with saline; C, perfusion pressure 120/60 mmHg with streptokinase; D, perfusion pressure 120/60 mmHg with saline. Reflow was defined as flow restoration determined by the ultrasonic flowmeter. RESULTS: Successful recanalization was obtained in six of six samples subjected to treatment A (100%), two of seven samples subjected to treatment B (28%), three of five samples subjected to treatment C (60%) and none of six samples subjected to treatment D (0%). Time to reflow was 23 +/- 11 min with treatment A, 76 +/- 24 min with treatment B, 66 +/- 25 min with treatment C, and > 90 min with treatment D. CONCLUSIONS: Our data suggest that the hemodynamic status determines the efficacy of streptokinase-induced thrombolysis, and that spontaneous clot lysis is more likely to occur at greater perfusion pressures. It is conceivable that the hypotensive reaction induced by streptokinase in the clinical setting may adversely affect angiographic patency, compared with that observed with other lytic agents such as tissue-type plasminogen activator.

Blood Pressure↗