Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 34
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Cell Death Differ ; 23(2): 270-8, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26184909

RESUMO

Ferroptosis is a form of regulated non-apoptotic cell death that has been implicated in several disease contexts. A better understanding of the ferroptotic death mechanism could lead to the development of new therapeutics for degenerative diseases, and a better understanding of how to induce ferroptosis in specific tumor contexts. We performed an unbiased genome-wide siRNA screen to find genetic suppressors of ferroptosis. We determined that loss of CARS, the cysteinyl-tRNA synthetase, suppresses ferroptosis induced by erastin, which inhibits the cystine-glutamate antiporter known as system xc(-). Knockdown of CARS inhibited erastin-induced death by preventing the induction of lipid reactive oxygen species, without altering iron homeostasis. Knockdown of CARS led to the accumulation of cystathionine, a metabolite on the transsulfuration pathway, and upregulated genes associated with serine biosynthesis and transsulfuration. In addition, inhibition of the transsulfuration pathway resensitized cells to erastin, even after CARS knockdown. These studies demonstrate a new mechanism of resistance to ferroptosis and may lead to strategies for inducing and suppressing ferroptosis in diverse contexts.


Assuntos
Aminoacil-tRNA Sintetases/genética , Apoptose , Aminoacil-tRNA Sintetases/metabolismo , Animais , Antineoplásicos/farmacologia , Vias Biossintéticas , Cistina/metabolismo , Resistencia a Medicamentos Antineoplásicos , Técnicas de Silenciamento de Genes , Ácido Glutâmico/farmacologia , Humanos , Células PC12 , Piperazinas/farmacologia , Ratos , Espécies Reativas de Oxigênio/metabolismo , Serina/biossíntese , Transdução de Sinais
2.
Geburtshilfe Frauenheilkd ; 74(10): 928-932, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25364032

RESUMO

Introduction: Diminished ovarian reserve (DOR) has been linked to certain subpopulations and distinct gene polymorphisms. It has even been hypothesized that the AB0 blood group system could be linked to ovarian reserve (OR) as reflected by early follicular phase follicle stimulating hormone (FSH) levels. Although estimation of OR is routinely done using levels of anti-Müllerian hormone (AMH), FSH, estradiol or inhibin B, the diagnostic accuracy of these markers is often limited. The aim of this study was to evaluate whether there is any correlation between IVF patients' AB0 blood group system and ART outcome. Methods: In this retrospective observational single-center study we investigated the outcome of 1889 IVF cycles carried out between 2005 and 2012 with regard to blood type and OR in different age groups (21-36 years and 37-43 years). The number of cumulus oocyte complexes (COCs) and metaphase II oocytes obtained after ovarian stimulation, fertilization rate (FR), pregnancy rate (PR) and birth rate (BR) were evaluated with respect to maternal age (21-36 and 37-43 years, respectively). Results: We found no significant differences in the average number of COCs after ovum pick-up in either of the age groups. Moreover, the mean number of MII oocytes and 2PN stages were similar for all blood type groups. As regards IVF outcome measured in terms of PR and BR, no significant differences were observed between the different blood groups. In conclusion, no correlation was found between blood type and female fertility. Discussion: The most precise definition of OR is determining the number of competent oocytes. Based on the finding of our study, the hypothesis that there is a correlation between OR and AB0 blood group system can be dismissed for Caucasian IVF patients.

3.
J Assist Reprod Genet ; 29(2): 131-5, 2012 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-22116647

RESUMO

BACKGROUND: To analyze the effects of embryo transfer (ET) quality on clinical pregnancy (CPR) and live birth delivery rates (LBDR). METHODS: In a retrospective study at a single, private infertility center between November 2005 and December 2009 one thousand fifty-five day-3 and day-5 ETs following IVF/ICSI/IMSI were evaluated. We analyzed the impact of an atraumatic ET with a soft catheter (ET 1), after external guidance (ET 2), after probing of the cervix with a stylet (ET 3), or after grasping the portio vaginalis with a tenaculum (ET 4) on CPR and LBDR. RESULTS: The use of external guidance showed a significantly reduced LBDR as compared to an atraumatic ET (26.0% vs. 32.5%). The lowest CPR and LBDR were found in ET 4. The application of stylets in cases of difficult ETs was superior to the use of external guidance. No differences in miscarriages between ET 1-4 were noted. CONCLUSIONS: Besides embryo culture and patient history, the quality of an ET might also have an important impact on pregnancy outcome. Techniques to ensure an atraumatic ET, such as mechanic uterine cavity length measurements, before starting treatment might help identify patients at risk for a difficult ET and lead to modified treatments, such as the primary use of a stylet. Limitation of study: retrospective analysis.


Assuntos
Transferência Embrionária/normas , Fertilização in vitro , Nascido Vivo , Aborto Espontâneo , Adulto , Coeficiente de Natalidade , Transferência Embrionária/métodos , Feminino , Humanos , Gravidez , Estudos Retrospectivos , Injeções de Esperma Intracitoplásmicas/métodos
4.
Breast J ; 7(6): 427-9, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11843856

RESUMO

The goal of screening mammograms is to provide early detection of breast cancer. As mammography technology improves, the ability to detect smaller and smaller suspicious lesions is increased. However, as mammography cannot always differentiate between malignant and benign lesions, biopsies are often needed. With the decreasing size of lesions seen on mammography, the size of the biopsy specimen needed for diagnosis also decreases. Thus, a smaller amount of normal breast tissue needs to be removed during a biopsy. For a majority of the small lesions, excision with a small margin of normal breast tissue is sufficient for diagnosis. The SiteSelect procedure utilizes stereotactic guidance to excise completely a tumor that is noted on a mammogram. The procedure can be performed under local anesthesia through a minimal incision (usually 1.5 cm). The SiteSelect biopsy procedure completely excises small tumors noted on the mammogram with minimal trauma to the breast tissue and with excellent cosmetic results. It is well tolerated by patients. For tumors requiring only local excision, such as atypical ductal hyperplasia or lobular carcinoma in situ, the SiteSelect procedure may be the only diagnostic procedure required.


Assuntos
Biópsia/métodos , Neoplasias da Mama/patologia , Neoplasias da Mama/diagnóstico por imagem , Neoplasias da Mama/cirurgia , Feminino , Humanos , Mamografia , Pessoa de Meia-Idade , Técnicas Estereotáxicas
5.
Can J Vet Res ; 63(4): 288-91, 1999 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-10534010

RESUMO

The effect of longeing and glucosamine supplementation on known biological markers of joint disease was studied in yearling quarter horses. Twenty-one yearling quarter horses were randomly assigned to one of 4 treatments: 1) longeing (longeing 20 min daily) supplement control (LN); 2) longeing/glucosamine (LG); 3) walking (mechanical walker for 120 min daily (WN)); and 4) walking/glucosamine (WG). Oral glucosamine was administered at 5.5 g b.i.d. weeks 1-4, 3.5 g b.i.d. during weeks 5-6, and 2.0 g b.i.d. during weeks 7-8. Serum was obtained weekly for 8 wk and analyzed for keratan sulfate and osteocalcin concentrations. Walked horses receiving glucosamine showed slight elevation in serum keratan sulfate compared to controls (P = 0.04). Glucosamine or longeing exercise had no significant effect (6 > or = 0.08) on serum osteocalcin concentrations. Under these conditions, longeing and/or glucosamine supplementation did not significantly alter serum concentrations of keratan sulfate or osteocalcin.


Assuntos
Glucosamina/farmacologia , Doenças dos Cavalos/prevenção & controle , Artropatias/veterinária , Condicionamento Físico Animal , Animais , Suplementos Nutricionais , Relação Dose-Resposta a Droga , Feminino , Glucosamina/administração & dosagem , Doenças dos Cavalos/fisiopatologia , Cavalos , Artropatias/fisiopatologia , Artropatias/prevenção & controle , Masculino
6.
Occup Environ Med ; 56(9): 602-5, 1999 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-10615292

RESUMO

OBJECTIVES: To present a case of asbestosis and small cell lung cancer caused by asbestos in a clutch refabricator. METHODS: Exposed surfaces of used clutches similar to those refabricated in the worker's workplace were rinsed, and the filtrate analysed by analytical transmission electron microscopy. Tissue samples were also analysed by this technique. RESULTS: Numerous chrysotile fibres of respirable dimensions and sufficient length to form ferruginous bodies (FBs) were detected from rinsed filtrates of the clutch. Bronchoalveolar lavage fluid contained many FBs, characteristic of asbestos bodies. Necropsy lung tissue showed grade 4 asbestosis and a small cell carcinoma in the right pulmonary hilum. Tissue analysis by light and analytical electron microscopy showed tissue burdens of coated and uncoated asbestos fibres greatly exceeding reported environmental concentrations (3810 FBs/g dry weight and 2,080,000 structures > or = 0.5 micron/g dry weight respectively). 72% Of the cores were identified as chrysotile. CONCLUSIONS: Clutch refabrication may lead to exposure to asbestos of sufficient magnitude to cause asbestosis and lung cancer.


Assuntos
Asbestose/etiologia , Carcinoma de Células Pequenas/etiologia , Neoplasias Pulmonares/etiologia , Doenças Profissionais/etiologia , Amianto/efeitos adversos , Automóveis , Evolução Fatal , Humanos , Masculino , Microscopia Eletrônica , Pessoa de Meia-Idade , Exposição Ocupacional/efeitos adversos
7.
Arch Androl ; 40(1): 59-66, 1998.
Artigo em Inglês | MEDLINE | ID: mdl-9466003

RESUMO

The objective of this study was to determine if spermatozoal reduction of the dyes methylene green to colorless and resazurin to pink or colorless was associated with the fertility potential of an equine semen sample. Fifty samples from 38 stallions were evaluated for the number of spermatozoa per milliliter and number of motile sperm per milliliter. Methylene green (20 micrograms/mL of semen) or resazurin (85 micrograms/mL of semen) was added to 3-mL aliquots of semen. Semen samples were identified as having low fertility potential (< 200 x 10(6) total cells/mL and < 140 x 10(6) motile cells/mL) or high fertility potential (> or = 200 x 10(6) total cells/mL and > or = 140 x 10(6) motile cells/mL). The sensitivities were 80% for the methylene green, 68% for the resazurin to pink, and 60% for the resazurin to colorless tests. The specificities were 80% for the methylene green, 79% for the resazurin to pink, and 92% for the resazurin to colorless tests. The overall accuracies were 80% for the methylene green test, 74% for the resazurin to pink test, and 76% for the resazurin to colorless tests. The methylene green and resazurin reduction tests can provide valuable information on the fertility potential of an equine semen sample.


Assuntos
Fertilidade/fisiologia , Sêmen/fisiologia , Xantenos , Animais , Cor , Corantes , Cavalos , Técnicas In Vitro , Indicadores e Reagentes , Masculino , Azul de Metileno/análogos & derivados , Oxazinas , Oxirredução , Valor Preditivo dos Testes
8.
Ultrastruct Pathol ; 21(4): 321-36, 1997.
Artigo em Inglês | MEDLINE | ID: mdl-9205997

RESUMO

Mesothelioma is a rare neoplasm that occurs most frequently in individuals with previous asbestos exposure. Differences for risk of development of asbestos-related mesothelioma and lung cancer have been attributed to the various types of asbestos, as well as to the dimension of the inhaled fibers. In the present study, 55 individuals with the pathological diagnosis of mesothelioma were evaluated as to ferruginous body and fiber content in lung tissue. The procedures used in the analysis included tissue digestion and analysis of the collected material for ferruginous bodies by light microscopy and for uncoated fibers by analytical transmission electron microscopy. Forty-six of the samples had ferruginous body concentrations of over 1000/per gram dry weight of lung tissue. The majority of the cores of these ferruginous bodies were amosite. Likewise, the most common uncoated asbestos fiber in the tissue was amosite. Only a small percentage of each type of asbestos would have been visible by light microscopy or even potentially by electron microscopy if the magnification was not sufficient to detect those with thin (< 0.2 micron) diameters. The consistent finding in most of the cases was a considerable presence of asbestos, often of mixed types.


Assuntos
Amianto/isolamento & purificação , Neoplasias Pulmonares/etiologia , Mesotelioma/etiologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Asbestose/etiologia , Carga Corporal (Radioterapia) , Feminino , Humanos , Neoplasias Pulmonares/mortalidade , Masculino , Mesotelioma/mortalidade , Pessoa de Meia-Idade , Doenças Profissionais/etiologia , Doenças Profissionais/mortalidade , Taxa de Sobrevida
9.
Arch Environ Health ; 51(6): 462-6, 1996.
Artigo em Inglês | MEDLINE | ID: mdl-9012326

RESUMO

Tissue was obtained from two American groups. The tissue was defined by ferruginous body levels of either < or = 1000 or > 1000 ferruginous bodies/g dry weight, and tissue was evaluated by light microscopy and analyzed by analytical transmission electron microscopy. Tissue was bleach digested, and uncoated asbestos fibers were classified with respect to type and size. In addition, some ferruginous body cores were analyzed. There was a wide range of uncoated fibers associated with each ferruginous body. A relationship was found between amosite fibers and ferruginous bodies. Other asbestos types were not associated significantly with the development of ferruginous bodies. Uncoated crocidolite fibers were not detected in these samples; this result further emphasizes the under-appreciated exposure of Americans to amosite. The levels of ferruginous bodies in both groups suggest exposures above those expected in the general population. Uncoated chrysotile levels were below the ranges reported previously for some general populations. The data suggest that there is a wide variation in the ratio of uncoated to coated fibers and that the amphibole in the United States is more likely to be amosite than crocidolite.


Assuntos
Amianto/isolamento & purificação , Pneumopatias/etiologia , Exposição Ocupacional/efeitos adversos , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Masculino , Microscopia Eletrônica , Pessoa de Meia-Idade , Fibras Minerais/classificação , Fumar , Estados Unidos
10.
Arch Environ Health ; 50(6): 462-5, 1995.
Artigo em Inglês | MEDLINE | ID: mdl-8572726

RESUMO

A 59-year-old man was exposed to chrysotile asbestos while rebuilding clutches. Analytical electron microscopy showed a chrysotile core in 72% of the ferruginous bodies from lung tissue. Long, uncoated chrysotile fibers were also present. Sufficient exposure to long chrysotile in jobs such as this appears to allow the majority of ferruginous bodies to be formed on chrysotile, an exception to the rule that most ferruginous bodies form on amphibole cores.


Assuntos
Asbestos Serpentinas/análise , Pneumopatias/patologia , Pulmão/química , Líquido da Lavagem Broncoalveolar/química , Carcinoma de Células Pequenas/diagnóstico , Humanos , Neoplasias Pulmonares/diagnóstico , Masculino , Pessoa de Meia-Idade , Exposição Ocupacional , Testes de Função Respiratória
11.
Am J Ind Med ; 27(2): 207-15, 1995 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-7755011

RESUMO

Tissue from an individual with a history of exposure to asbestos and other dust was referred for particulate analysis. The digested material was reviewed by light microscopy to establish the numbers of ferruginous bodies per gram of tissue. Typical asbestos bodies were found at levels consistent with occupational exposure. A second type of elongated ferruginous body was formed on a thicker transparent core which suggested the minerals were sheet silicates. The number of ferruginous bodies with nonasbestos cores was over four times the number of asbestos cored ferruginous bodies. Electron microscopy was used to confirm the core composition of both populations and also to establish the levels of uncoated fibers. The nonasbestos ferruginous bodies were predominantly formed on talc.


Assuntos
Adenocarcinoma/etiologia , Amianto/análise , Neoplasias Pulmonares/etiologia , Doenças Profissionais/etiologia , Talco/análise , Humanos , Masculino , Microscopia Eletrônica , Microscopia Eletrônica de Varredura , Pessoa de Meia-Idade
12.
Br J Ind Med ; 50(11): 1032-8, 1993 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-8280628

RESUMO

Classical ferruginous bodies in tissue samples are considered to be markers of past exposure to asbestos. Recent studies have shown that the presence of ferruginous bodies in bronchoalveolar lavage (BAL) fluid correlates with past exposure to asbestos and offers a more sensitive reference than occupational history. Lavage samples from five subjects who had worked in foundries were evaluated by light microscopy for the presence of ferruginous bodies and by transmission electron microscopy for both characterisation of the uncoated fibre burden and analysis of the cores of the ferruginous bodies. All samples at lower magnification (light microscopy (200 x)) contained ferruginous bodies that were externally consistent with asbestos bodies. At higher magnification (400 x), a separate population from this group could be identified by the presence of a thin black ribbon. Transmission electron microscopy of the core materials of ferruginous bodies and comparable uncoated particulates supported the reliability of higher magnification light microscopy for distinguishing most of those non-asbestos cores; however, a population of transparent non-asbestos cored ferruginous bodies were also shown to exist.


Assuntos
Amianto/análise , Líquido da Lavagem Broncoalveolar/química , Ferro/análise , Exposição Ocupacional , Idoso , Poeira , Humanos , Masculino , Microscopia Eletrônica , Pessoa de Meia-Idade
14.
Ann Pharmacother ; 26(12): 1530-4, 1992 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-1482811

RESUMO

OBJECTIVE: To review current information relevant to the use of aspirin for preventing vascular death in women, and to provide recommendations based on this information. DATA SOURCES: References from pertinent articles are identified throughout the text. DATA SYNTHESIS: Based on current information, low-dose aspirin is not recommended as primary prevention for cardiovascular death in women; efforts are better focused at promoting risk-factor reduction. Low-dose aspirin is recommended for reducing further cardiovascular morbidity and mortality in women with known cardiovascular disease. Women presenting with unstable angina or myocardial infarction should receive aspirin 325 mg as soon as the diagnosis is confirmed, and this dosage should be continued on a chronic basis. Women who have experienced transient ischemic attacks or ischemic stroke should receive aspirin 1000 mg/d, with a subsequent dosage reduction to 325 mg/d in patients who do not tolerate the higher dose. CONCLUSIONS: Current recommendations are based on the results of studies that involved few women. Further investigation of antiplatelet agents for primary and secondary prevention of vascular death in women is needed.


Assuntos
Aspirina/administração & dosagem , Doenças Cardiovasculares/prevenção & controle , Transtornos Cerebrovasculares/prevenção & controle , Angina Instável/tratamento farmacológico , Angina Instável/mortalidade , Aspirina/efeitos adversos , Aspirina/uso terapêutico , Doenças Cardiovasculares/tratamento farmacológico , Doenças Cardiovasculares/mortalidade , Transtornos Cerebrovasculares/tratamento farmacológico , Transtornos Cerebrovasculares/mortalidade , Feminino , Humanos , Fatores de Risco
15.
J Burn Care Rehabil ; 12(6): 516-20, 1991.
Artigo em Inglês | MEDLINE | ID: mdl-1779004

RESUMO

Liquid propane causes a severe, deep thermal injury in unprotected tissue. Delayed surgical intervention, as for thermal burns, has been the gold standard of treatment. An animal model of liquid-propane injury was devised to document injury, to demonstrate a better method of protection, and to define an appropriate management protocol. Twenty-eight rats were classified into four groups: unprotected tissue (n = 8), skin covered with wool (n = 8), skin covered with Neoprene (Wm. H. Horn & Brothers Inc., Philadelphia, Pa.) (n = 8), and skin covered with wool plus Neoprene (n = 4). Each group was subdivided into two exposure times: 6 seconds and 30 seconds. The mean temperatures +/- standard error of the mean of the various tissue levels initially and at 6 and 30 seconds of exposure were determined. Histologic examination demonstrated that full-thickness tissue necrosis occurred in unprotected and wool-covered tissue. Areas that were covered with Neoprene showed intact skin and subcutaneous tissue with underlying muscle necrosis. Examination of the tissue that was covered with wool plus Neoprene showed no histologic damage. There was no sign of tissue regeneration at the wound periphery, and there was no histologic difference in any group, whether the examination took place at 1 or 5 days after injury. This study demonstrated that the best form of protection appears to be a wool glove liner covered with a Neoprene glove. The histologic evidence suggests that a liquid-propane injury to unprotected tissue should be managed aggressively with early excision and grafting.


Assuntos
Congelamento das Extremidades/induzido quimicamente , Propano , Roupa de Proteção , Animais , Congelamento , Congelamento das Extremidades/prevenção & controle , Congelamento das Extremidades/cirurgia , Membro Posterior/lesões , Masculino , Neopreno , Ratos , Ratos Endogâmicos ,
16.
J Burn Care Rehabil ; 12(2): 136-9, 1991.
Artigo em Inglês | MEDLINE | ID: mdl-2050720

RESUMO

Exposure of skin to liquid propane causes a severe freeze injury. This cutaneous injury has the appearance of a partial-thickness thermal injury of indeterminate depth, but the deep tissue damage is greater than is at first apparent. A case history is presented that illustrates the severity of this particular mechanism of injury and the need for adequate safety precautions.


Assuntos
Queimaduras Químicas/etiologia , Propano/efeitos adversos , Acidentes de Trabalho/prevenção & controle , Acidentes de Trabalho/estatística & dados numéricos , Amputação Cirúrgica , Queimaduras Químicas/patologia , Desbridamento , Congelamento , Humanos , Masculino , Pessoa de Meia-Idade , Necrose , Transplante de Pele
17.
Am J Ind Med ; 19(5): 619-28, 1991.
Artigo em Inglês | MEDLINE | ID: mdl-1647134

RESUMO

Fiberoptic bronchoscopy has permitted the development of lavage procedures for the collection of lung washes. In certain disease states this material may contain large numbers of phagocytic cells (macrophages and neutrophils). Since these phagocytes are the predominant "dust scavenger cells" in the lung, the assessment of their particulate burden as well as that of the overall lavage material has been suggested as a potentially important diagnostic tool. The studies to date have shown that the presence of ferruginous bodies is an indication of past occupational exposure. In the present study, a digestion procedure was carried out on bronchoalveolar lavage material collected from individuals who were occupationally exposed to asbestos and from samples obtained from the general population. The parameters used for distinguishing the source of these samples included both light microscopy assessment of the filters for the presence of ferruginous bodies and electron microscopic screening for the presence of uncoated fibers.


Assuntos
Amianto/análise , Líquido da Lavagem Broncoalveolar/patologia , Exposição Ocupacional , Adulto , Idoso , Amianto Amosita , Asbestos Serpentinas , Broncoscopia , Feminino , Tecnologia de Fibra Óptica , Humanos , Masculino , Microscopia Eletrônica , Pessoa de Meia-Idade , Fagócitos/patologia
19.
Am Rev Respir Dis ; 142(4): 843-7, 1990 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-2171386

RESUMO

Autopsy samples from eight former shipyard workers were collected from lung parenchyma, tracheal lymph nodes, and pleural plaques. The tissue from each respective area was prepared by a modified bleach digestion technique, and the residue was collected on a 0.2-micron pore polycarbonate or 0.22-micron mixed cellulose ester filter. Quantitation of ferruginous bodies and uncoated fibers was done by light and transmission electron microscopy, respectively. Differences in the asbestos burden were noted for each site. Ferruginous bodies were observed in both parenchyma and nodes but not in plaques. Three subjects were found to have more ferruginous bodies per gram dry weight in their lymph nodes than in their lung parenchyma. Likewise, all subjects were found to have more uncoated fibers per gram in the nodes than in the parenchyma. Amphibole and chrysotile fibers were noted in the lung and extrapulmonary sites, with chrysotile being the predominant asbestiform in plaques. The majority of the uncoated fibers in both the nodes and the plaques were less than or equal to 5 microns in length. However, some fibers with dimensions conforming to the "Stanton hypothesis" reached both areas. These residual patterns most likely reflect the impact of clearance on lung burden as opposed to the eventual accumulation and stasis in the extrapulmonary areas.


Assuntos
Amianto/química , Pulmão/química , Linfonodos/química , Exposição Ocupacional , Pleura/química , Idoso , Idoso de 80 Anos ou mais , Amiantos Anfibólicos , Asbestos Serpentinas , Asbestose/metabolismo , Asbestose/patologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Pleura/patologia , Dióxido de Silício/química
20.
J Am Coll Cardiol ; 14(6): 1491-500, 1989 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-2809009

RESUMO

The purpose of this study was to critically evaluate the usefulness of postexercise regional myocardial thallium-201 clearance for identifying disease in individual coronary arteries. Exercise and redistribution planar imaging studies were performed in 114 subjects, including 19 normal volunteers and 95 patients undergoing cardiac catheterization (70 with and 25 without greater than or equal to 50% narrowing in one or more coronary arteries). Thallium clearance was measured from predefined myocardial regions corresponding to the left anterior descending, left circumflex and right coronary arteries and was expressed as the percent decrease in activity at 4 h, assuming monoexponential clearance. In regions perfused by a normal or insignificantly diseased coronary artery, mean 4 h clearance was 58.9 +/- 9.4% for normal volunteers, 43.1 +/- 15.5% for catheterized patients without coronary artery disease and 36.3 +/- 24.9% for catheterized patients with coronary artery disease (p less than 0.001 patients with coronary artery disease versus normal volunteers). Clearance from normal regions was significantly associated with two measures of exercise performance: percent of predicted maximal heart rate achieved (r = 0.49) and exercise duration (r = 0.35). In regions perfused by a stenotic coronary artery, mean clearance was lower (31.1 +/- 19.8%) but was not significantly different from that in normal regions in the same patients. Clearance from diseased regions was also associated with maximal exercise heart rate (r = 0.28) and exercise duration (r = 0.41), but not with percent coronary artery stenosis (r = 0.02). After taking exercise performance into account, the number of diseased vessels or the presence or absence of disease in a given vessel had little influence on regional thallium clearance. Although measurement of regional post-exercise thallium clearance may help to identify stenotic coronary arteries in selected patients, variability related to exercise performance and other physiologic and technical factors greatly limits the clinical usefulness of absolute thallium clearance measurements.


Assuntos
Doença das Coronárias/metabolismo , Vasos Coronários/metabolismo , Radioisótopos de Tálio/metabolismo , Adulto , Idoso , Angiografia Coronária , Doença das Coronárias/diagnóstico por imagem , Doença das Coronárias/fisiopatologia , Vasos Coronários/diagnóstico por imagem , Exercício Físico , Feminino , Frequência Cardíaca , Humanos , Masculino , Pessoa de Meia-Idade , Cintilografia
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...