Activity of biogenic silver nanoparticles against isolates of Prototheca species from bovine mastitis.

Prototheca spp. cause numerous infections in a wide variety of species, including treatment-unresponsive mastitis. Thus, the search for an effective therapy is essential. Silver nanoparticles are compounds with high therapeutic potential. This study aimed to evaluate the susceptibility profile and morphological changes in Prototheca spp. treated with biogenic silver nanoparticles (Bio-AgNP). The algaecide activity was evaluated in microplates by microdilution method, resulting in a MIC50 of 30 µg ml-1 and a MIC90 of 60 µg ml-1 . Scanning electron microscopy demonstrated changes in the surface of Prototheca bovis cells following treatment. The algaecide activity of Bio-AgNP suggests a therapeutic potential as a novel approach for the control of Prototheca spp. in bovine mastitis.

Effect of thermally deposited siloxane-methacrylate coating on bonding to glass fibre posts.

AIM: To evaluate the alterations promoted by a thermally deposited siloxane-methacrylate coating on the surface of glass fibre posts and their effect on the bond strength of resin-core materials to the posts. METHODOLOGY: Fibre post surfaces were treated with experimental thermally deposited siloxane-methacrylate coatings or clinically available treatments (i.e. hydrogen peroxide and methylene chloride); nontreated posts were used as controls. The contact angles formed between the post surface and the water/adhesive were measured with a tensiometer. Scanning electron microscopy and electron dispersive spectroscopy were used to examine the topographies and chemical changes in the post surfaces following treatment. Surface roughness was evaluated with laser interferometry. Core resin was bonded to the fibre posts, and microtensile bond strength testing was subsequently performed. The data were individually submitted to anova and Tukey's tests (α = 0.05). RESULTS: The water contact angle was reduced significantly (P < 0.05) by the thermally deposited siloxane-methacrylate coating. All treatments significantly increased the adhesive contact angle (P ≤ 0.016) compared to the control as well as the surface roughness (P ≤ 0.006) and the amount of Si on post surfaces. Greater percentages of Si were observed for the thermally deposited coating. The bond strength to the posts was significantly improved by the thermally deposited coating (P < 0.05), whereas the other treatments did not differ from the control. CONCLUSION: Treating the surface of glass fibre posts with a thermally deposited siloxane-methacrylate coating improved the bond strength to resin-based materials. The coating could be performed by manufacturers of glass fibre posts in order to reduce the number of clinical steps required for luting posts into root canals.

Using thermography as a diagnostic tool for omphalitis on newborn calves.

The objective was to verify if thermography is able to detect inflammatory signs on the skin surface by comparing the umbilical region of healthy calves and calves presenting omphalitis. Twenty healthy calves (control group) had their lateral umbilical region and abdominal region examined with a thermal imaging camera in order to obtain a regional thermograph. The thermographic examination was then performed on 27 calves (Omphalitis group) presenting omphalitis diagnosed by physical examination. The maximum temperature of the lateral umbilical region in calves (aged < 30 days) was 35.7°C ± 1.8 for the control group and 37.0°C ± 1.1 for the omphalitis group and was significantly different (p = 0.002). No difference was found on the temperature of the abdominal umbilical region. In the abdominal and lateral region the highest temperature site was differently positioned between the groups. In conclusion, thermography is able to detect inflammatory signs on the skin of newborn calves and has advantages as a non-invasive, fast and safe method of supporting veterinary diagnosis.

Implications of mitotic and meiotic irregularities in common beans (Phaseolus vulgaris L.).

The common bean has great social and economic importance in Brazil and is the subject of a high number of publications, especially in the fields of genetics and breeding. Breeding programs aim to increase grain yield; however, mitosis and meiosis represent under explored research areas that have a direct impact on grain yield. Therefore, the study of cell division could be another tool available to bean geneticists and breeders. The aim of this study was to investigate irregularities occurring during the cell cycle and meiosis in common bean. The common bean cultivar used was BRSMG Talismã, which owing to its high yield and grain quality is recommended for cultivation in Brazil. We classified the interphase nuclei, estimated the mitotic and meiotic index, grain pollen viability, and percentage of abnormalities in both processes. The mitotic index was 4.1%, the interphase nucleus was non-reticulated, and 19% of dividing somatic cells showed abnormal behavior. Meiosis also presented irregularities resulting in a meiotic index of 44.6%. Viability of pollen grains was 94.3%. These results indicate that the common bean cultivar BRSMG Talismã possesses repair mechanisms that compensate for changes by producing a large number of pollen grains. Another important strategy adopted by bean plants to ensure stability is the elimination of abnormal cells by apoptosis. As the common bean cultivar BRSMG Talismã is recommended for cultivation because of its good agronomic performance, it can be concluded that mitotic and meiotic irregularities have no negative influence on its grain quality and yield.

Analysis of the prevalence of polymorphisms in the glutathione S transferase gene (GST) in cataract patients from Goiânia.

The aim of this study was to determine the prevalence of polymorphisms in the glutathione S-transferase genes GSTM1 and GSTT1 in patients with lens opacity (cataract). Peripheral blood samples were obtained from male and female patients (N = 23) with cataract. The GSTM1 and GSTT1 polymorphic regions were amplified by polymerase chain reaction, and the amplification products were electrophoresed on a 2% agarose gel. The obtained bands were by staining with ethidium bromide. The results were compared by a chi-square test using the BioEstat software (v.5.0). The frequencies of the GSTM1- and GSTT1-null genotypes were higher than those of the GSTM1- and GSTT1-present genotypes. The frequency of GSTT1-null genotypes was approximately 1.7 times higher than that of GSTM1, which was a statistically significant difference (P = 0.0019). Although a consensus remains to be reached on the correlation between genetic polymorphisms in GSTs and cataract susceptibility, the observations from most scientific studies are similar to those reported in this study. Thus, we conclude that the absence of these genes, particularly GSTT1, is correlated with the development of lens opacity.

Analysis of the GSTM1-null polymorphism in patients with pterygium from Goiânia, Goiás Brazil.

The first reports about pterygium date back to Hippocrates, and this disease still threatens vision health around the world. Pterygium is a formation of fibrous tissue consisting of highly vascularized epithelial and subepithelial tissue that grows excessively and with an abnormal shape on the cornea. Many physical and biological factors are associated with the pathogenesis of pterygium, including heat, dust, and other particles in the atmosphere, and immunological mechanisms, mechanisms involving extracellular matrix reorganization, growth factors, cytokines, apoptosis, and angiogenesis. The aim of this study was to further investigate the association between polymorphisms in GSTM1 and the formation of pterygium. We collected peripheral blood samples from 90 patients diagnosed with pterygium and from 23 subjects with-out the disease in order to perform molecular analysis of the GSTM1 gene. Subjects with one or two copies of the GSTM1 allele had a normal genotype while those without any copies of the allele had a null geno-type. The chi-square test or the Fisher exact test was performed in order to investigate possible associations between the molecular analysis and the risk of pterygium. A significant difference between the frequency of the GSTM1-null genotype in patient and control groups was identified. However, sub-group analysis found that the GSTM1-null genotype was statistically significant in men, but not in women, and in Caucasians, but not in Brown or Black groups. Furthermore, the GSTM1-null geno-type was not related to any of the risk factors analyzed: cases in family, occupational exposure, smoking, hypertension, and diabetes.

Pterygium in patients from Goiânia, Goiás, Brazil.

Pterygium is an inflammatory and degenerative ocular surface disease in which the conjunctiva on the cornea grows to form a fibrous tissue in the shape of a triangle. The disorder may be characterized by cell proliferation, inflammatory processes, fibrosis, angiogenesis, and destruction of the extracellular matrix. The anomaly is considered a degenerative eye disease and is erroneously confused with cataract. It displays similar features to those of tumors, such as local invasion, metaplasia of epithelial cells, presence of oncogenic viruses (human papilloma virus), inactivation of tumor suppressor genes (e.g., p53), and loss of heterozygosity. The treatment of pterygium is based on factors such as the evolution and progression of the disease, risk factors, symptoms, and patient age. Considerations about the best technique for the surgical removal of pterygium remain controversial, and complications and recurrence are very common. The development of new surgical techniques and adjuvant drugs is thus necessary. This study aims to analyze and compare the frequency of the GSTT1 genotypes in relation to pterygium through statistical analyzes in order to build a genotypic profile for the Replicon patients. The genotypic profile of the GSTT1-null polymorphism in Goiânia showed no significant difference when the frequency of the null genotype was compared between the control and experimental groups. The null genotype was more frequent in the population studied. Furthermore, the GSTT1 genotype was not related to the analyzed risk factors for pterygium, namely gender, ethnicity, family history, occupational exposure, smoking, hypertension, and diabetes.

[Digital transformation in urology-opportunity, risk or necessity?] / Digitale Transformation in der Urologie ­ Chance, Risiko oder Notwendigkeit?

Ultimately, new (digital) techniques and artificial intelligence (AI) applications are changing the working environment in urology. This can be an opportunity for further development, but also a change which is not desired. Adjustments to work processes may be necessary. So-called disruptive processes lead to fundamental changes. In the context of the digital transformation, our way of working is changing. Classic hierarchies, working hours, and working environments are dissolving in favor of creative and flexible working models and corporate structures. Clinics and practices in urology must prepare themselves for changing requirements and be able to provide answers.

Antigen-presenting cells from nonresponder strain 2 guinea pigs are fully competent to present bovine insulin B chain to responder strain 13 T cells. Evidence against a determinant selection model and in favor of a clonal deletion model of immune response gene function.

To test directly the determinant selection hypothesis of immune response gene function, we primed strain 13 T lymphocytes in vitro with allogeneic bovine insulin pulsed strain 2 macrophages. Strain 2 macrophages were found to be fully competent to present bovine insulin B chain to strain 13 T cells despite the fact that strain 2 guinea pigs are normally totally unresponsive to this antigen. These results are incompatible with a strict interpretation of the determinant selection hypothesis, which would have predicted that strain 2 macrophages would have been restricted to the presentation of A chain loop determinants. In addition, a comparison of the reactivity profiles of self-Ia- and allo-Ia-restricted strain 13 T cells to a series of synthetic B chain peptide fragments revealed that the allo-Ia-restricted populations could be activated by autologous guinea pig insulin. Taken together, these observations strongly suggest that the clonal deletion of self-reactive cells is likely to be I region restricted and that nonresponsiveness to any protein antigen may result from a restriction in the T cell repertoire that is generated during ontogeny by a clonal deletion mechanism of tolerance to self.

Evaluation of the ethanol intake on the Calomys callosus seminal vesicle structure.

The effects of chronic alcohol ingestion on the structure of the glandular epithelium of the seminal vesicle of the rodent Calomys callosus were analyzed in 24 adult animals aged 3 months divided into three experimental groups. The control group received a solid diet and tap water, the alcoholic group received the same solid diet and ethanol P.A. diluted 20% in water (v/v) for 4 months. The abstinent group received the same liquid diet of the alcoholic one for the same period and after that the alcoholic diet was changed by water for a period of 3 months. After treatment, all animals were anesthetized, weighed and sacrificed. At the end of treatment, mean body weight did not differ between animal groups. The glandular epithelial cells of the alcoholic and abstinent groups showed atrophy and ultrastructural alterations such as the presence of altered nuclei, intense dilatation of the cisterns of the granular endoplasmic reticulum, intense digestive vacuoles and lipid droplets. Ethanol ingestion provokes marked lesions on the epithelium of the seminal vesicle probably interfering on the glandular secretion.

Identification and assessment of COPD exacerbations.

Chronic Obstructive Pulmonary Disease (COPD) exacerbations play a central role in the disease natural history of the disease, affecting its overall severity, decreasing pulmonary function, worsening underlying co-morbidities, impairing quality of life (QoL) and leading to severe morbidity and mortality. Therefore, identification and correct assessment of COPD exacerbations is paramount, given it will strongly influence therapy success. For the identification of exacerbations, several questionnaires exist, with varying degrees of complexity. However, most questionnaires remain of limited clinical utility, and symptom scales seem to be more useful in clinical practice. In the assessment of exacerbations, the type and degree of severity should be ascertained in order to define the management setting and optimize treatment options. Still, a consensual and universal classification system to assess the severity and type of an exacerbation is lacking, and there are no established criteria for less severely ill patients not requiring hospital assessment. This might lead to under-reporting of minor to moderate exacerbations, which has an impact on patients' health status. There is a clear unmet need to develop clinically useful questionnaires and a comprehensive system to evaluate the severity of exacerbations that can be used in all settings, from primary health care to general hospitals.

Baclofen, an agonist at peripheral GABAB receptors, induces antinociception via activation of TEA-sensitive potassium channels.

BACKGROUND AND PURPOSE: Central anti-nociceptive actions of baclofen involve activation of K+ channels. Here we assessed what types of K+ channel might participate in the peripheral anti-nociception induced by baclofen. EXPERIMENTAL APPROACH: Nociceptive thresholds to mechanical stimulation in rat paws treated with intraplantar prostaglandin E2.(PGE2) to induce hyperalgesia were measured 3 h after PGE2 injection. Other agents were also given by intraplantar injection. KEY RESULTS: Baclofen elicited a dose-dependent (15 - 240 microg per paw) anti-nociceptive effect. An intermediate dose of baclofen (60 microg) did not produce antinociception in the contralateral paw, showing its peripheral site of action. The GABAB receptor antagonist saclofen (12.5 - 100 microg per paw) antagonized, in a dose-dependent manner, peripheral antinociception induced by baclofen (60 microg), suggesting a specific effect. This antinociceptive action of baclofen was unaffected by bicuculline, GABAA receptor antagonist (80 microg per paw), or by (1,2,5,6 tetrahydropyridin-4-yl) methylphosphinic acid, GABAC receptor antagonist (20 microg per paw). The peripheral antinociception induced by baclofen (60 microg) was reversed, in a dose-dependent manner, by the voltage-dependent K+ channel blockers tetraethylammonium (7.5 - 30 microg per paw) and 4-aminopyridine (2.5 - 10 microg per paw). The blockers of other K+ channels, glibenclamide (160 microg), tolbutamide (320 microg), charybdotoxin (2 microg), dequalinium (50 microg) and caesium (500 microg) had no effect. CONCLUSIONS AND IMPLICATIONS: This study provides evidence that the peripheral antinociceptive effect of the GABAB receptor agonist baclofen results from the activation of tetraethylammonium-sensitive K+ channels. Other K+ channels appear not to be involved.

Morphological alterations on the prostate of Calomys callosus submitted to chronic ethanol ingestion.

The objective of the present study was to assess the possible toxic effects of chronic alcohol ingestion on the ultrastructure of the glandular epithelium of the prostate of the rodent Calomys callosus, in order to contribute to the understanding of the consequences of alcohol abuse for the morphology of the male reproductive apparatus. Sixteen adult animals aged three months were divided into two experimental groups. The control group received a solid diet and tap water, and the alcoholic group received the same solid diet and ethanol P.A. diluted 20% in water (v/v). After 120 days of treatment, all animals were anesthetized, weighed and sacrificed. At the end of treatment, mean body weight did not differ between control and alcoholic animals. The prostate epithelial cells of the alcoholic group showed intense atrophy and ultrastructural alterations such as the presence of lipid droplets, altered nuclei, ruptured mitochondrial cristae, and intense dilatation of the cisterns of the granular endoplasmic reticulum. It was concluded that 20% ethanol provokes marked lesions on the epithelium of the prostate probably interfering on the glandular secretion.

Optimal treatment sequence in COPD: Can a consensus be found?

There is currently no consensus on the treatment sequence in chronic obstructive pulmonary disease (COPD), although it is recognized that early diagnosis is of paramount importance to start treatment in the early stages of the disease. Although it is fairly consensual that initial treatment should be with an inhaled short-acting beta agonist, a short-acting muscarinic antagonist, a long-acting beta-agonist or a long-acting muscarinic antagonist. As the disease progresses, several therapeutic options are available, and which to choose at each disease stage remains controversial. When and in which patients to use dual bronchodilation? When to use inhaled corticosteroids? And triple therapy? Are the existing non-inhaled therapies, such as mucolytic agents, antibiotics, phosphodiesterase-4 inhibitors, methylxanthines and immunostimulating agents, useful? If so, which patients would benefit? Should co-morbidities be taken into account when choosing COPD therapy for a patient? This paper reviews current guidelines and available evidence and proposes a therapeutic scheme for COPD patients. We also propose a treatment algorithm in the hope that it will help physicians to decide the best approach for their patients. The authors conclude that, at present, a full consensus on optimal treatment sequence in COPD cannot be found, mainly due to disease heterogeneity and lack of biomarkers to guide treatment. For the time being, and although some therapeutic approaches are consensual, treatment of COPD should be patient-oriented.

Risk factors related to the appearance of umbilical disorders in dairy calves / [Fatores de risco relacionados ao surgimento de afecções umbilicais em bezerros leiteiros]

The objective of this study was to determine the types of calve housing used in dairy farms, the prevalence of umbilical disorders and related risk factors. The 16 farms studied were visited to characterize the types of installation and possible risk factors, as well as information obtained from a questionnaire applied to the farmers. 806 Holstein calves were physically examined, in addition to collecting blood samples for the evaluation of Failures in Passive Immunity Transfer (FPIT), in animals that manifested inflammatory omphalopathies, and were also submitted to ultrasound examination. The prevalence of omphalopathies was assessed by Fisher's test, and multivariate logistic regression to assess risk factors. Eight types of installation were found: tropical house, suspended cage, collective stall, collective picket, Argentinean type, single-story cage, individual stall, and collective picket with chain. Omphalopathies accounted for 6.45% of the calves. Small size farms (up to 99 lactation cows) had high risk for umbilical disorders, ground floor collective calves, without side protection, with sand floor, in closed sheds and without heatstroke were considered risk factors for omphalopathies. Adequate colostrum and umbilical antisepsis are not associated with disease, its appearance being related to the housing conditions of the animals.(AU)

O objetivo deste estudo foi determinar os tipos de alojamento para bezerros leiteiros, a prevalência de onfalopatias e os fatores de risco relacionados. As 16 fazendas estudadas foram visitadas buscando-se caracterizar os tipos de instalação e os possíveis fatores de risco, além de informações obtidas de um questionário aplicado aos fazendeiros. Foram examinados fisicamente 806 bezerros da raça Holandesa, além da coleta de amostras de sangue, para avaliação da falha de transferência de imunidade passiva (FTIP), nos animais que manifestaram onfalopatias inflamatórias, sendo submetidos também ao exame ultrassonográfico. A prevalência das onfalopatias foi avaliada por teste de Fisher, e foi feita regressão logística multivariada a fim de se avaliarem os fatores de risco. Verificou-se oito tipos de instalação: casinha tropical, gaiola suspensa, baia coletiva, piquete coletivo, bezerreiro tipo argentino, gaiola térrea, baia individual e piquete coletivo com corrente. As onfalopatias corresponderam a 6,45% dos bezerros. Os bezerreiros coletivos térreos, sem proteções laterais, com piso de areia, borracha, concreto ou madeira, em galpões fechados, sem insolação, com alta densidade animal, antissepsia umbilical realizada por três dias e FTIP acima de 50% foram considerados fatores de risco para onfalopatias e possuem relação com o bezerreiro, sendo decisivas para evitar essas condições a colostragem e a antissepsia umbilical adequadas.(AU)

Electrophysiology of phagocytic membranes. I. Potassium-dependent slow membrane hyperpolarizations in mice macrophages.

Electrophysiological properties of activated mouse macrophages cultured in vitro were studied using microelectrode techniques. In a high percentage of the individual cells analysed a slow hyperpolarization (SH) was observed with a concomitant decrease (2--4 times) of the input resistance. Increasing doses of tetraethyl ammonium progressively reduce the amplitude of the SH and at a concentration of 15 mM complete blockade of the phenomena is observed. Valinomycin, at a concentration of 10(-7) M produces rapid and permanent hyperpolarization, with a shift in the membrane potential to about --50 mV. These data strongly support the previously proposed hypothesis that the development of SH is due to an increase in the membrane permeability to potassium ions.

Electrophysiology of phagocytic membranes. III. Evidence for a calcium-dependent potassium permeability change during slow hyperpolarizations of activated macrophages.

The roles of potassium and calcium in the slow hyperpolarizations of membranes of activated macrophages are investigated using standard intracellular electrical recording techniques. The amplitude of spontaneous slow hyperpolarizations decreases as a logarithmic function of the external potassium concentration in the culture medium. Similar dependence on the potassium gradient is observed when different levels of membrane potentials are imposed by constant current injection. The reversal potential for electrically evoked slow hyperpolarizations is -90 mV. A 10-fold increase in external potassium concentration causes a 60 mV shift of the reversal potential towards zero. Divalent cation ionophores (A23187 and X537A) can induce slow hyperpolarization responses in quiescent cells or permanent hyperpolarization in spontaneously active cells. The amplitude of the ionophore-induced hyperpolarizations is reduced by an increase in external potassium concentration in a manner consistent with data on slow hyperpolarization responses in the absence of ionophore. The calcium antagonist, verapamil, depresses the slow hyperpolarization responses at the concentration of 10(-5) M. It is suggested that the development of the hyperpolarizing response is due to a calcium-dependent potassium channel. The data support the assumption that spontaneous and artificially elicited slow hyperpolarization responses share a common calcium-dependent mechanism.

Electrophysiology of phagocytic membranes. II. Membrane potential and induction of slow hyperpolarizations in activated macrophages.

The potential differences measured on the cell surface and after penetration into the cytoplasm of activated macrophages are described. Linear regressions are made of the measured potential differences as functions of the tip potential of each microelectrode. The surface potential of the macrophage is not significantly different from zero. Mouse macrophages have a transmembrane potential of--26 mV, whereas in guinea-pig cells this value is--18 mV. The input resistances of guinea-pig cells are higher than those of mouse macrophages. The cytoplasmic location of the electrode was characterized both by fluorescent dye injection and by electric criteria. Slow membrane hyperpolarizations are directly elicited by mechanical stimulation. Electric responses evoked by current pulses were further characterized. Our results lead to the extablishment of objective criteria to validate intracellular recordings from macrophage.

Laser balloon angioplasty: clinical, angiographic and histologic results.

Laser balloon angioplasty combines conventional coronary angioplasty with laser energy to transiently heat vascular tissue. Laser balloon angioplasty, was performed in 21 patients (aged 56 +/- 13 years), including 10 patients treated urgently after acute failure of conventional angioplasty and 11 patients treated with elective laser balloon angioplasty. Immediately after conventional angioplasty, laser doses (1 to 10 doses of 205 to 380 J each) were delivered during inflation of the laser balloon to a pressure of 4 atm. Seven (70%) of 10 patients with acute failure of conventional angioplasty were successfully treated with laser balloon angioplasty, but 3 (30%) were unsuccessfully treated with the laser procedure and required emergency coronary artery bypass surgery. In all three failures, the 3 mm laser balloon angioplasty catheter was not the optimal size for the vessel. In the 11 patients treated with elective laser balloon angioplasty (reference diameter 2.94 +/- 0.22 mm), the minimal luminal diameter increased from 0.45 +/- 0.25 to 1.85 +/- 0.46 mm after conventional angioplasty and to 2.44 +/- 0.29 mm after laser balloon angioplasty (p less than 0.001). This corresponded to a decrease in diameter stenosis from 84 +/- 9% before to 35 +/- 16% after conventional angioplasty and to 15 +/- 10% after laser balloon angioplasty (p less than 0.001). There were no instances of myocardial infarction, emergency coronary artery bypass surgery or death and no acute complications related to delivery of laser energy in this group. Follow-up coronary angiography was performed 5.5 +/- 1.1 months after laser balloon angioplasty in 18 patients discharged from the hospital after a successful procedure. Ten patients (56%) had angiographic restenosis, defined as recurrent diameter stenosis greater than 50%. Six patients were subsequently treated by directional coronary atherectomy, which revealed intimal proliferation indistinguishable from that in patients with restenosis after conventional angioplasty. In conclusion, laser balloon angioplasty may be effective in sealing severe coronary dissections and reversing abrupt closure associated with failed conventional angioplasty. After uncomplicated conventional angioplasty, laser balloon angioplasty improves immediate luminal dimensions, but restenosis appears to be mediated by intimal hyperplasia, similar to that seen after conventional angioplasty.

Novel approach to the analysis of restenosis after the use of three new coronary devices.

Restenosis after coronary intervention has remained a vexing problem despite the introduction of nearly 24 newer coronary interventional devices. To more clearly evaluate the potential impact of three such new devices on restenosis, coronary lumen diameters were measured before, immediately after and at 6 months after intervention, and restenosis was analyzed using continuous geometric techniques. Lumen diameters were measured before and immediately after intervention in 223 coronary vessels treated with one of three new devices: a single Palmaz-Schatz stent (n = 87), directional atherectomy (n = 125) and laser balloon angioplasty (n = 11); 184 (83%) of the patients underwent follow-up angiography 6 months after treatment. The immediate increase in lumen diameter produced by the intervention (acute gain) and the subsequent reduction in lumen diameter between the time of intervention to 6 month follow-up study (late loss) were examined. For each of the three interventions, the restenosis rate at follow-up study was analyzed using a traditional dichotomous definition (greater than or equal to 50% diameter stenosis), as well as a novel graphic technique. Although the apparent restenosis rates differed significantly among the three interventions (19% for stents, 31% for atherectomy and 50% for laser balloon angioplasty; p = 0.02), late loss among the three interventions was equivalent (average 1 mm; p = 0.91). There were, however, marked differences in the acute gain achieved by the three interventions: 2.6 mm for stents, 2.2 mm for atherectomy and 2 mm for laser balloon angioplasty; p less than 0.001). It was these differences in acute gain rather than late loss that explained the observed differences in restenosis rate.(ABSTRACT TRUNCATED AT 250 WORDS)