Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 46
Filtrar
Mais filtros











Base de dados
Intervalo de ano de publicação
1.
Stroke ; 32(11): 2472-9, 2001 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-11692003

RESUMO

BACKGROUND AND PURPOSE: Atherosclerosis occurs later and is less extensive in intracranial arteries than in extracranial arteries. However, the mechanisms responsible are poorly understood. A previous study has suggested a better antioxidant protection of intracranial arteries. METHODS: To assess the influence of age on arterial activity of antioxidant enzymes and atherogenesis, we compared intracranial and extracranial arteries of humans of different ages who retrospectively lacked confounding classic risk factors (48 premature fetuses aged 6.4+/-0.8 months [mean+/-SD], 58 children aged 7.9+/-3.8 years, 42 adults aged 42.5+/-5.1 years, and 40 elderly subjects aged 71.8+/-3.4 years; all males). Lesions were quantified by computer-assisted imaging analysis of sections of the middle cerebral and basilar arteries, the left anterior descending coronary artery, the common carotid artery, and the abdominal aorta. Macrophages, apolipoprotein B, oxidized LDL, and matrix metalloproteinase-9 in lesions were determined by immunocytochemistry. The effect of aging on atherogenesis was then compared with that on the activity of 4 antioxidant enzymes in the arterial wall. RESULTS: Atherosclerosis was 6- to 19-fold greater (P<0.01) in extracranial arteries than in intracranial arteries, and it increased linearly with age. Intracranial arteries showed significantly greater antioxidant enzyme activities than did extracranial arteries. However, the antioxidant protection of intracranial arteries decreased significantly in older age, coinciding with a marked acceleration of atherogenesis. An increase in matrix metalloproteinase-9 protein expression and in gelatinolytic activity consistent with the degree of intracranial atherosclerosis was also observed. CONCLUSIONS: These results suggest that a greater activity of antioxidant enzymes in intracranial arteries may contribute to their greater resistance to atherogenesis and that with increasing age intracranial arteries respond with accelerated atherogenesis when their antioxidant protection decreases relatively more than that of extracranial arteries.


Assuntos
Artérias Cerebrais/enzimologia , Arteriosclerose Intracraniana/enzimologia , Arteriosclerose Intracraniana/etiologia , Adulto , Fatores Etários , Idoso , Antioxidantes/análise , Apolipoproteínas B/análise , Apolipoproteínas B/imunologia , Artérias/química , Artérias/enzimologia , Artérias/patologia , Artérias Cerebrais/química , Artérias Cerebrais/patologia , Criança , Progressão da Doença , Humanos , Imuno-Histoquímica , Arteriosclerose Intracraniana/patologia , Peroxidação de Lipídeos , Lipoproteínas LDL/análise , Lipoproteínas LDL/imunologia , Masculino , Metaloproteinase 9 da Matriz/metabolismo , Estudos Retrospectivos , Fatores de Risco , Superóxido Dismutase/análise , Superóxido Dismutase/imunologia
2.
Radiographics ; 21(4): 957-64, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11452070

RESUMO

The term autoimmune thyroiditis encompasses multiple inflammatory conditions of the thyroid gland, each with variable clinical manifestations. The more acute forms, silent (painless) thyroiditis and postpartum thyroiditis, are associated with transient hyperthyroidism and are sometimes mistaken for Graves disease. The chronic form, Hashimoto thyroiditis (chronic autoimmune thyroiditis), results in goiter and eventual hypothyroidism unless it is recognized and treated promptly. Thyroid uptake measurements and scintigraphic findings (usually obtained with technetium-99m or iodine-123) play a complementary role along with thyroid function testing in differentiating autoimmune thyroiditis from other thyroid diseases, thereby influencing treatment. In some cases, histologic evaluation of biopsy specimens is required to yield the definitive diagnosis. Knowledge of the entire spectrum of these disorders is essential for appropriate case management.


Assuntos
Tireoidite Autoimune/diagnóstico por imagem , Diagnóstico Diferencial , Humanos , Cintilografia , Tireoidite Autoimune/patologia
3.
Curr Atheroscler Rep ; 2(1): 64-71, 2000 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-11122726

RESUMO

Because of the original observation by Altschul et al., that nicotinic acid (niacin), not nicotinamide, in pharmacologic doses lowered human serum cholesterol levels, an avalanche of reports have been published over the past 45 years on the plasma lipid-regulating properties of this drug and its beneficial cardiovascular effects. A myriad of studies that have examined efficacy, safety, adverse effects, and pharmacologic properties of niacin rendered convincing evidence that niacin, used alone or combined with other agents, has favorable effects on serum lipoprotein regulation and on containment of atherothrombotic cardiovascular diseases. However, because of the unusual side effect profile of niacin and the availability of various formulations of this drug, niacin must be used prudently and with careful instruction and monitoring of patients. This review summarizes the pertinent and recent literature on niacin that impacts its therapeutic use. We also discuss some controversial issues and personal clinical experience and opinions on this topic.


Assuntos
Anticolesterolemiantes/administração & dosagem , Hipercolesterolemia/tratamento farmacológico , Niacina/administração & dosagem , Anticolesterolemiantes/efeitos adversos , Anticolesterolemiantes/farmacologia , Relação Dose-Resposta a Droga , Quimioterapia Combinada , Humanos , Metabolismo dos Lipídeos , Niacina/efeitos adversos , Niacina/farmacologia
4.
Am J Cardiol ; 86(1): 46-52, 2000 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-10867091
5.
Am J Cardiol ; 85(9): 1100-5, 2000 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-10781759

RESUMO

This multicenter trial evaluated the safety and efficacy of escalating doses of Niaspan (niacin extended-release tablets) and placebo (administered once-a-day at bedtime) in patients with primary hyperlipidemia on the percent change from baseline in levels of low-density lipoprotein (LDL) cholesterol and apolipoprotein B. Extended-release niacin was initiated at a dose of 375 mg/day, raised to 500 mg/day, and further increased in 500-mg increments at 4-week intervals to a maximum of 3,000 mg/day. A total of 131 patients (n = 87, extended-release niacin; n = 44, placebo) were treated for 25 weeks with study medication after a 6-week diet lead-in/drug washout phase and 2-week baseline LDL cholesterol stability phase. Significant decreases from baseline in levels of LDL cholesterol and apolipoprotein B became apparent with the 500-mg/day dose and were consistent at all subsequent doses (p < or =0. 05), reaching 21% and 20%, respectively, at the 3,000-mg/day dose. Significant increases from baseline in levels of high-density lipoprotein cholesterol became apparent with the 500-mg/day dose and were consistent at all subsequent doses (p < or = 0.05), reaching 30% at the 3,000-mg dose. Significant decreases from baseline in triglycerides and lipoprotein(a) occurred at the 1,000-mg dose and were apparent at all subsequent doses (p < or =0.05), reaching 44% and 26%, respectively, at the 3,000-mg dose. The most common adverse events were flushing and gastrointestinal disturbance. Transaminase increases were relatively small, and the proportion of patients who developed liver function abnormalities on extended-release niacin was not significantly different from placebo. Thus, extended-release niacin was generally well tolerated and demonstrated a dose-related ability to alter favorably most elements of the lipid profile.


Assuntos
Hiperlipidemias/tratamento farmacológico , Niacina/administração & dosagem , Adulto , Idoso , Apolipoproteínas B/sangue , LDL-Colesterol/sangue , Método Duplo-Cego , Feminino , Humanos , Hiperlipidemias/sangue , Masculino , Pessoa de Meia-Idade , Resultado do Tratamento
6.
Stroke ; 30(9): 1907-15, 1999 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-10471444

RESUMO

BACKGROUND AND PURPOSE: Calcium-channel blockers (CCBs) reduce systolic blood pressure and stroke-related mortality in stroke-prone spontaneously hypertensive rats (SPSHR). Brain ischemia is associated with loss of intracellular antioxidants. Increased formation of oxygen radicals and oxidation of LDL may enhance arterial vasoconstriction by various mechanisms. CCBs that also exert antioxidative properties in vitro may therefore be particularly useful. To investigate such antioxidant effects in vivo, we determined several parameters of LDL oxidation in SPSHR treated with two 1,4-dihydropyridine-type (1,4-DHP) CCBs of different lipophilic properties and compared them with antioxidant-treated and untreated controls. We also tested whether these drugs decrease the formation of oxidation-specific epitopes in arteries. METHODS: Five groups of 9 to 14 SPSHR each (aged 8 weeks) were treated with 80 mg/kg body wt per day nifedipine, 1 mg or 0.3 mg/kg body wt per day lacidipine, vitamin E (100 IU/d), or carrier for 5 weeks. A group of Wistar-Kyoto rats was used as normotensive control. Plasma samples were taken, and LDL was isolated by ultracentrifugation. Then LDL was exposed to oxygen radicals generated by xanthine/xanthine oxidase reaction (2 mmol/L xanthine+100 mU/mL xanthine oxidase), and several parameters of oxidation were determined. The presence of native apolipoprotein B and oxidation-specific epitopes in the carotid and middle cerebral arteries was determined immunocytochemically. RESULTS: 1,4-DHP CCBs completely prevented mortality. Normotensive Wistar-Kyoto rats showed less oxidation than control SPSHR. Plasma lipoperoxide levels were 0.87+/-0.27 micromol/L in control SPSHR, 0.69+/-0.19 and 0.63+/-0.20 micromol/L in the groups treated with 0.3 and 1 mg lacidipine, respectively, and 0.68+/-0.23 micromol/L in nifedipine-treated animals (P<0.05 versus control SPSHR for all values). Both CCBs significantly decreased formation of conjugated dienes and prolonged the lag time in LDL exposed to oxygen radicals. Similarly, lipoperoxides and malondialdehyde were significantly reduced (P<0.05). Reduced relative electrophoretic mobility and increased trinitrobenzenesulfonic acid reactivity of LDL from treated rats (P<0.01) also indicated that fewer lysine residues of apolipoprotein B were oxidatively modified in the presence of 1,4-DHP CCBs. Finally, these drugs reduced the intimal presence of apolipoprotein B and oxidized LDL (oxidation-specific epitopes) in carotid and middle cerebral arteries. CONCLUSIONS: In the SPSHR model, 1,4-DHP CCBs reduce plasma and LDL oxidation and formation of oxidation-specific epitopes and prolong survival independently of blood pressure modifications. Our results support the concept that the in vivo protective effect of these drugs on cerebral ischemia and stroke may in part result from inhibition of oxidative processes.


Assuntos
Artérias/metabolismo , Bloqueadores dos Canais de Cálcio/farmacologia , Transtornos Cerebrovasculares/genética , Di-Hidropiridinas/farmacologia , Predisposição Genética para Doença , Lipoproteínas LDL/antagonistas & inibidores , Ratos Endogâmicos SHR/genética , Animais , Antioxidantes/farmacologia , Apolipoproteínas B/metabolismo , Artérias/efeitos dos fármacos , Transtornos Cerebrovasculares/mortalidade , Epitopos/efeitos dos fármacos , Epitopos/metabolismo , Imuno-Histoquímica , Lipoproteínas LDL/sangue , Masculino , Oxirredução/efeitos dos fármacos , Ratos , Ratos Endogâmicos SHR/metabolismo , Ratos Endogâmicos WKY , Valores de Referência , Vitamina E/farmacologia
7.
J Ultrasound Med ; 17(2): 123-6, 1998 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-9527572

RESUMO

Color Doppler sonographic detection of tumor flow within superficial melanoma metastases was investigated to determine if tumor size, vessel size, or vessel number influences signal detection. Color Doppler imaging of 32 pathologically proved melanoma metastases was performed at 6 MHz with color Doppler imaging parameters optimized for each lesion scanned. All lesions were measured in three dimensions and the presence or absence of internal flow was documented. Seven surgically excised metastases underwent immunohistochemical staining for endothelial markers. Internal flow was detected in 21 of 32 masses and was completely absent in 11. In comparison to all masses without flow, the masses with flow had significantly greater anteroposterior dimensions (P < 0.00036) and volumes (P < 0.01). Histologically, mean vessel diameter in masses with flow was significantly greater (P < 0.05) than in those without flow, but mean vessel number was not significantly different. In conclusion, detectability of tumor blood flow in superficial melanoma metastasis may be related more to tumor size and vessel size than vessel number. Failure to detect color signal within a superficial melanoma mass does not indicate a lack of internal vascularity.


Assuntos
Melanoma/irrigação sanguínea , Neoplasias Cutâneas/irrigação sanguínea , Ultrassonografia Doppler em Cores , Adulto , Idoso , Idoso de 80 Anos ou mais , Antígenos CD34 , Vasos Sanguíneos/diagnóstico por imagem , Vasos Sanguíneos/patologia , Corantes , Endotélio Vascular/patologia , Humanos , Imuno-Histoquímica , Melanoma/diagnóstico por imagem , Melanoma/patologia , Melanoma/secundário , Pessoa de Meia-Idade , Fluxo Sanguíneo Regional , Neoplasias Cutâneas/diagnóstico por imagem , Neoplasias Cutâneas/patologia , Neoplasias Cutâneas/secundário
9.
AJR Am J Roentgenol ; 170(2): 459-63, 1998 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-9456964

RESUMO

OBJECTIVE: The purpose of this study was to describe the sonographic appearances of melanoma metastases of the skin, subcutaneous tissues, and superficial lymph nodes. MATERIALS AND METHODS: Gray-scale sonography was performed on 31 superficial melanoma metastases in 18 patients. Discreteness of borders, contours, echogenicity, echotexture, and degree of acoustic through-transmission were evaluated for each lesion. Color Doppler sonography was also performed on 25 of the 31 lesions, by which the amount of internal color flow was qualitatively assessed. RESULTS: Twenty-eight (90%) of the 31 metastases had well-defined borders. Contours were smooth in 17 (55%), lobulated in 12 (39%), and spiculated in two (6%). Nineteen metastases (61%) were hypoechoic to muscle, 10 (32%) were isoechoic, and two (6%) were hyperechoic. Echotexture was homogeneous in six lesions (19%), mildly heterogeneous in 13 (42%), moderately heterogeneous in 11 (35%), and markedly heterogeneous in one (3%). Twenty-two lesions (71%) showed enhanced acoustic through-transmission. Of the 25 melanoma metastases for which we performed color Doppler sonography, 18 (72%) had internal arterial color flow and seven (28%) did not. The flow was characterized as mild in 13 (72%) of 18, moderate in four (22%), and marked in one (6%). CONCLUSION: On sonography, superficial melanoma metastases typically are well-defined hypoechoic lesions with smooth or lobulated contours, mild to moderate heterogeneity, and enhanced acoustic through-transmission. Internal flow revealed by color Doppler sonography is present in many, but not all, superficial melanoma metastases.


Assuntos
Melanoma/diagnóstico por imagem , Melanoma/secundário , Neoplasias Cutâneas/diagnóstico por imagem , Neoplasias de Tecidos Moles/diagnóstico por imagem , Neoplasias de Tecidos Moles/secundário , Ultrassonografia Doppler em Cores , Feminino , Humanos , Metástase Linfática , Masculino , Pessoa de Meia-Idade , Neoplasias Cutâneas/patologia
10.
Am J Cardiol ; 82(12A): 74U-81U; discussion 85U-86U, 1998 Dec 17.
Artigo em Inglês | MEDLINE | ID: mdl-9915666

RESUMO

Crystalline nicotinic acid (immediate-release niacin) is effective therapy for lipoprotein regulation and cardiovascular risk reduction. However, inconvenient regimens and unpleasant side effects decrease compliance. Sustained-release formulations designed to circumvent these difficulties increase hepatotoxicity. Niaspan, a new US Food and Drug Administration (FDA)-approved, once-daily, extended-release form, has been found effective and safe in short-term trials. The long-term efficacy and safety of Niaspan lipid monotherapy was studied in 517 patients (aged 21-75 years) for < or =96 weeks in dosages < or =3,000 mg/day. Primary efficacy endpoints were low-density lipoprotein (LDL) cholesterol and apolipoprotein B (apo B) changes from baseline; secondary efficacy endpoints were changes in total cholesterol, triglycerides, high-density lipoprotein (HDL) cholesterol, lipoprotein(a), and total cholesterol/HDL-cholesterol ratio; safety data included adverse events and laboratory values over the 2-year study period. LDL-cholesterol levels decreased significantly: 18% at week 48 and 20% at week 96; apo B reduction was similar (16% decrease at week 48 and 19% at week 96). Large elevations in HDL cholesterol (26%, week 48; 28%, week 96) allowed only modest decreases in total cholesterol (12% and 13%, respectively), whereas total cholesterol/HDL-cholesterol ratio decreased by almost one third. Triglyceride and lipoprotein(a) levels were decreased by 27% and 30%, respectively (week 48), and by 28% and 40%, respectively (week 96). All changes from baseline were significant (p <0.001). Niaspan was generally well tolerated, although flushing was common (75%); however, there was a progressive decrease in flushing with time from 3.3 episodes in the first month to < or = 1 episode by week 48. Aspirin was used by one third of patients before Niaspan dosing to minimize flushing episodes. Although serious adverse events occurred in about 10% of patients, none were considered probably or definitely related to Niaspan. Adverse events in general varied widely, but their true relation to the study drug is difficult to ascertain without a placebo (control) group. No deaths occurred. There were statistically significant changes in hepatic transaminases, alkaline phosphatase, direct bilirubin, phosphorus, glucose, amylase, and uric acid. However, these changes were mostly small and are not likely to be biologically or clinically significant (the decrease in phosphorus is a new finding in niacin therapy). No myopathy was observed. Thus, this long-term study confirms the earlier short-term findings that Niaspan is safe and effective as monotherapy in plasma lipoprotein regulation.


Assuntos
Hipercolesterolemia/tratamento farmacológico , Hipolipemiantes/administração & dosagem , Niacina/administração & dosagem , Adulto , Idoso , Ensaios Clínicos como Assunto , Preparações de Ação Retardada , Feminino , Humanos , Hipercolesterolemia/sangue , Hipolipemiantes/efeitos adversos , Lipídeos/sangue , Masculino , Pessoa de Meia-Idade , Niacina/efeitos adversos
11.
Am J Cardiol ; 82(12A): 82U-84U; discussion 85-86U, 1998 Dec 17.
Artigo em Inglês | MEDLINE | ID: mdl-9915667

RESUMO

Combined use of niacin with a statin is an attractive option, since these types of medication have the best records in clinical trials for reduction in cardiovascular events and improvement in progression/regression of coronary lesions. In early use, the niacin-statin combination generated a few case reports documenting severe myopathy and rhabdomyolysis. Subsequent prospective trials in >400 patients, however, have not encountered myopathy. This experience includes 165 patients who took a statin in combination with Niaspan, a new, extended-release niacin administered once nightly. Hepatic toxicity with immediate-release niacin and with Niaspan used in combination with statins has been minimal. However, substantial transaminase elevations occurred with the use of a sustained-release niacin (Nicobid) given twice daily. The niacin-statin treatment regimens gave augmented low-density lipoprotein (LDL)-cholesterol reduction along with favorable changes in high-density lipoprotein (HDL) cholesterol, lipoprotein(a), and triglycerides. This combination therapy can be used safely as long as (1) careful attention is given to niacin formulation and dosing; (2) liver functions are monitored; and (3) patients are educated to recognize symptoms of myopathy. However, special caution should apply to use of niacin in combination with high doses of statins, or with statins introduced into clinical practice in 1997 or later, since little experience has accumulated in these circumstances.


Assuntos
Anticolesterolemiantes/uso terapêutico , Hiperlipidemias/tratamento farmacológico , Niacina/uso terapêutico , Ensaios Clínicos como Assunto , Preparações de Ação Retardada , Quimioterapia Combinada , Humanos , Hipolipemiantes/uso terapêutico
12.
Am J Cardiol ; 82(12A): 29U-34U; discussion 39U-41U, 1998 Dec 17.
Artigo em Inglês | MEDLINE | ID: mdl-9915660

RESUMO

Immediate-release niacin manifests beneficial effects in cardiovascular disease with respect to dyslipidemic states. It lowers low-density lipoprotein (LDL) cholesterol, triglycerides, lipoprotein(a), and apoprotein B; at the same time, it increases high-density lipoprotein (HDL) cholesterol, HDL2, and apoprotein A-I. However, use of crystalline niacin has drawbacks: therapy requires multidose regimens, and side effects include flushing and pruritus. Slowing absorption with sustained-release formulations succeeds in decreasing flushing and increasing tolerance, but increases in hepatic enzyme levels have raised safety concerns. A new extended-release, once-daily formulation of niacin (Niaspan) shows promise in minimizing flushing while avoiding hepatotoxicity. A multicenter, randomized, double-blind clinical trial of Niaspan enrolled 122 patients with confirmed diagnosis of primary dyslipidemia (LDL cholesterol >4.14 mmol/L [160 mg/dL] and triglycerides <9 mmol/L [800 mg/dL]) into 3 treatment groups: (1) Niaspan 1,000 mg/day; (2) Niaspan 2,000 mg/day; and (3) placebo. The primary treatment endpoint was LDL-cholesterol level. This endpoint was not significantly affected by placebo (0.2% increase), but Niaspan decreased LDL cholesterol by 5.8% (1,000 mg/day) and 14.6% (2,000 mg/day) (p <0.001). Likewise, with placebo there were significant changes in total cholesterol, triglycerides, lipoprotein(a), and apoprotein B, whereas both Niaspan 1,000 and 2,000 mg/day significantly (p <0.001) decreased these parameters. In addition, both Niaspan groups showed significant (p <0.001) increases in HDL cholesterol (17% and 23%, respectively), including HDL subfractions. With respect to flushing, 20% of the placebo group reported at least 1 episode, whereas 88% and 83% of the Niaspon 1,000- and 2,000-mg/day groups, respectively, reported episodes. There was no hepatotoxicity as liver enzyme levels remained within clinically accepted limits in all treatment groups. However, Niaspan 2,000 mg/day showed a significant increase in aspartate aminotransferase compared with baseline and placebo. This trial demonstrated a cholesterol-modifying effect of Niaspan consistent with those reported for niacin, but demonstrated a better tolerance for flushing. Moreover, in contrast to sustained-release formulations, Niaspan showed relatively mild hepatic effects.


Assuntos
Hiperlipidemias/tratamento farmacológico , Hipolipemiantes/administração & dosagem , Niacina/administração & dosagem , LDL-Colesterol/sangue , Preparações de Ação Retardada , Feminino , Rubor/induzido quimicamente , Humanos , Hiperlipidemias/sangue , Hipolipemiantes/efeitos adversos , Lipídeos/sangue , Masculino , Pessoa de Meia-Idade , Niacina/efeitos adversos , Ensaios Clínicos Controlados Aleatórios como Assunto
13.
J Magn Reson Imaging ; 7(4): 689-95, 1997.
Artigo em Inglês | MEDLINE | ID: mdl-9243390

RESUMO

Papillary projections are distinctive pathologic features of epithelial ovarian neoplasms. We sought to determine whether these structures have recognizable features on MRI. A search of a database of 125 patients on whom MRI was performed with pelvic phased-array coil and abdominal surgical exploration was performed for suspected gynecologic disease identified 15 patients who had either MRI reports or pathology reports mentioning papillary projections in an adnexal mass. The MR images were reviewed to characterize the size, structure, and signal intensity of papillary projections. Pathologic correlation was performed on these and on four surgical specimens imaged with high resolution technique. Pathologic correlation showed that larger papillary projections had a distinctive structure of a fibrous stalk supporting clumps of edematous papillae with signal intensity similar to that of fluid on T2-weighted images. Smaller papillae showed nondescript intracystic projections of intermediate signal intensity on T2-weighted images. All papillary projections in vivo enhanced after injection of gadopentetate dimeglumine. Papillary projections have an appearance on MRI that reflects their histologic structure.


Assuntos
Cistadenocarcinoma Papilar/patologia , Imageamento por Ressonância Magnética/métodos , Neoplasias Ovarianas/patologia , Ovário/patologia , Anexos Uterinos/patologia , Meios de Contraste , Combinação de Medicamentos , Feminino , Gadolínio , Gadolínio DTPA , Humanos , Meglumina , Pessoa de Meia-Idade , Compostos Organometálicos , Ácido Pentético/análogos & derivados
14.
Angiology ; 47(11): 1027-32, 1996 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-8921750

RESUMO

Despite the significant advances made in the understanding and treatment of coronary artery disease much remains unclear about the pathogenesis of this complex atherothrombotic process. Atherogenesis may reflect a combination of multiple factors interacting with one another leading to coronary artery occlusion. One potential participant may be endothelin-1 (ET-1), a potent mitogenic vasoconstrictor. The presence of endothelin within saphenous veins before insertion and after removal during coronary artery bypass grafting (CABG) because of bypass closure, within internal mammary arteries before and after surgical intervention, and within native coronary artery segments resected during CABG was demonstrated immunocytochemically with an antiendothelin antibody and aminoethyl carbazole as the indicator chromogen. Increased amounts of ET-1 were observed in failed venous grafts, in damaged internal mammary artery grafts, and in vessels of the myocardium. These results suggest that ET-1 may play a significant pathophysiologic role in the evolution of coronary heart disease.


Assuntos
Doença das Coronárias/fisiopatologia , Endotelina-1/fisiologia , Adulto , Idoso , Idoso de 80 Anos ou mais , Ponte de Artéria Coronária , Vasos Coronários/patologia , Endotélio Vascular/patologia , Feminino , Humanos , Imuno-Histoquímica , Masculino , Pessoa de Meia-Idade
15.
Int J Clin Pharmacol Ther ; 32(5): 235-9, 1994 May.
Artigo em Inglês | MEDLINE | ID: mdl-7921517

RESUMO

Recombinant human insulin-like growth factor-I (rhIGF-I) was evaluated in 7 healthy males to determine the pharmacodynamics on glucose and insulin levels. Each subject received an initial intravenous infusion of normal saline and on the following day, rhIGF-I at a rate of 21.4 micrograms/kg/h over 7 hours. The subjects' fasting baseline glucose and insulin levels were not statistically different (p > 0.05) from their pre-dose levels. Compared to the saline (control) infusion, glucose levels were statistically lower (p < 0.05) 2 hours into the rhIGF-I infusion, and were suppressed until the subjects consumed a standard lunch (4 hours into the infusion). Insulin levels demonstrated a similar response to rhIGF-I, but decreases in insulin levels occurred after the rhIGF-I hypoglycemic effect. Therefore, suppression of insulin levels may be due to hypoglycemia rather than a direct action of rhIGF-I. This trial demonstrated the desired rhIGF-I effect of lowering subjects' glucose levels without clinically significant hypoglycemia. This finding suggests that rhIGF-I may have potential clinical utility in hyperglycemic or insulin resistant states.


Assuntos
Glicemia/química , Fator de Crescimento Insulin-Like I/farmacologia , Insulina/sangue , Proteínas Recombinantes/farmacologia , Adulto , Humanos , Infusões Intravenosas , Fator de Crescimento Insulin-Like I/administração & dosagem , Masculino , Proteínas Recombinantes/administração & dosagem , Método Simples-Cego , Fatores de Tempo
16.
Biochem Biophys Res Commun ; 193(3): 1145-51, 1993 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-8323538

RESUMO

Immunohistochemical studies have localized thrombospondin (TSP), a platelet adhesive protein, to the atherosclerotic plaque. To investigate how TSP may become incorporated in the plaque, we evaluated the interaction of TSP with human plasma lipoproteins and apolipoproteins. Chylomicrons, VLDL, LDL, HDL, and apolipoproteins AI, AII, C were immobilized on microtiter plates. Binding to TSP was measured directly with [125I]TSP. Labeled TSP bound saturably to all the plasma lipoproteins tested, showing the highest capacity for binding to VLDL. This binding to VLDL was maximal in the presence of 1 mM CaCl2 and MgCl2 and only partially inhibited with EDTA. The binding was inhibited totally by incubation with fluid-phase lipoproteins, apolipoproteins or anti-TSP monoclonal antibodies. The dissociation constants (Kd) for VLDL and apo C were 153 nM and 150 nM, respectively. Thus, TSP exhibits specific and saturable binding with high affinity to VLDL, perhaps mediated by its surface apo C. This binding may facilitate TSP incorporation into nascent atherosclerotic plaques and delivery of VLDL cholesterol into these lesions.


Assuntos
Apolipoproteínas/metabolismo , Lipoproteínas/sangue , Glicoproteínas da Membrana de Plaquetas/metabolismo , Plaquetas/metabolismo , Cálcio/farmacologia , Cátions Bivalentes/farmacologia , Ácido Egtázico/farmacologia , Humanos , Cinética , Magnésio/farmacologia , Glicoproteínas da Membrana de Plaquetas/isolamento & purificação , Ligação Proteica , Trombospondinas
17.
Clin Nucl Med ; 18(4): 302-6, 1993 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-8386991

RESUMO

The term "thyroiditis" refers to several syndromes of differing etiology. Chronic or Hashimoto's thyroiditis (HT), an autoimmune disorder that is manifested by goiter and hypothyroidism, is by far the most common of these syndromes. Subacute thyroiditis (SAT) encompasses two distinct syndromes: subacute granulomatous thyroiditis (SAGT) and subacute lymphocytic thyroiditis (SLT). SAGT is viral in origin and usually presents with neck tenderness and hyperthyroid symptoms, while SLT, which is likely to be an autoimmune entity, results in goiter and transient hyperthyroidism. SLT is often seen in the postpartum period and is referred to as postpartum thyroiditis (PPT). Less common forms of thyroiditis include Riedel's struma, which is characterized by extensive fibrosis of the thyroid gland, and acute suppurative thyroiditis, which is a bacterial infection. Twenty patients with goiter were evaluated by thyroid scintigraphy. They were ultimately diagnosed as having either HT (14), SAGT (3), SLT (1), or PPT (2). Their scan findings were correlated with both clinical presentations as well as in vitro laboratory analysis.


Assuntos
Glândula Tireoide/diagnóstico por imagem , Tireoidite Autoimune/diagnóstico por imagem , Tireoidite Subaguda/diagnóstico por imagem , Adulto , Feminino , Humanos , Radioisótopos do Iodo , Masculino , Pessoa de Meia-Idade , Transtornos Puerperais/diagnóstico , Transtornos Puerperais/diagnóstico por imagem , Cintilografia , Pertecnetato Tc 99m de Sódio , Testes de Função Tireóidea , Tireoidite Autoimune/diagnóstico , Tireoidite Subaguda/diagnóstico
18.
J Clin Pharmacol ; 33(4): 366-72, 1993 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-8473552

RESUMO

Recombinant human insulin-like growth factor-I (rhIGF-I) produced by expression in a yeast vector was evaluated in seven normal men to determine effects on plasma glucose and insulin levels. Each subject received an initial intravenous infusion of normal saline and on the following day, rhIGF-I at a rate of 21.4 micrograms/kg/hour. Each infusion lasted for 7 hours. The subjects' fasting baseline glucose and insulin levels were not statistically different (P > .05) from their pre-dose levels. Compared with the saline (control) infusion, serum glucose levels were statistically lower (P < .05) 2 hours into the rhIGF-I infusion. These lower glucose levels were maintained until the subjects consumed a standard lunch (4 hours into the infusion). Insulin levels demonstrated a similar response to rhIGF-I, but decreases in insulin levels occurred after the rhIGF-I hypoglycemic effect. This observation suggests that suppression of insulin levels may be due to secondary hypoglycemia rather than to a direct rhIGF-I effect. This study demonstrated the desired rhIGF-I effect of lowering subjects' glucose levels without clinically significant hypoglycemia. This finding suggests that rhIGF-I may have potential clinical utility in hyperglycemic states.


Assuntos
Glicemia/análise , Fator de Crescimento Insulin-Like I/farmacologia , Insulina/sangue , Adulto , Jejum/sangue , Humanos , Hipoglicemia/induzido quimicamente , Infusões Intravenosas , Masculino , Proteínas Recombinantes/farmacologia , Método Simples-Cego
19.
J Nutr ; 122(11): 2153-60, 1992 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-1432254

RESUMO

The National Cholesterol Education Program (NCEP) guidelines recommend dietary restriction of fat and cholesterol to reduce high circulating cholesterol concentrations in adult Americans. Thus, diet counselors recommend consumption of fewer than four egg yolks per week. The present protocol was designed to determine whether the efficacy of an NCEP diet would be reduced by the incorporation of 12 modified eggs per week, and whether the resulting low fat, high cholesterol diet would increase serum lipid concentrations in adults with initial undesirably high (5.17-7.76 mmol/L) concentrations of serum total cholesterol. Feeding a controlled ration to laying hens produced modified eggs that consistently contained more vitamin E and iodine, and more unsaturated fat, than generic eggs. Subjects were randomly assigned to and NCEP diet including either no whole eggs or 12 whole study eggs a week. Ninety-eight subjects completed the parallel study. Subjects in both groups significantly reduced their serum total, LDL and HDL cholesterol (P < 0.001 for total and LDL cholesterol, P < 0.02 for HDL cholesterol) over the 6 wk of study. No significant differences were found between diet groups. We conclude that the study eggs did not adversely affect measured lipid concentrations when added to a low fat diet that favorably alters lipid profiles in hypercholesterolemic subjects.


Assuntos
Colesterol/sangue , Dieta , Ovos , Índice de Massa Corporal , HDL-Colesterol/sangue , LDL-Colesterol/sangue , Feminino , Humanos , Masculino , Distribuição Aleatória , Glândula Tireoide/fisiologia
20.
Thromb Haemost ; 67(6): 607-11, 1992 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-1509400

RESUMO

Thrombospondin (TSP), a large glycoprotein present in platelets, and various normal and tumor tissues, has recently been shown to promote cell adhesion and platelet aggregation. Most importantly because TSP has been shown to promote metastasis of melanoma tumor cells to the lung in a murine model (1) and since thromboembolic events commonly occur in patients afflicted with metastatic tumors, we explored the role of TSP in human cancer by measuring TSP blood levels in patients with various malignant neoplasms. Blood TSP levels were measured by indirect enzyme-linked immunoadsorbent assay (ELISA) from 20 control subjects, 22 patients with gastrointestinal (GI) cancer, 18 patients with breast cancer, and 17 patients with lung cancer. Control subjects consisted both of healthy subjects and acutely ill patients with no malignancies. TSP levels of both healthy and acutely ill controls were found to range between 245-440 ng/ml with a mean of 365 ng/ml. In contrast, elevated levels of TSP greater than the mean value of 400 ng/ml for controls ranging between 590-3,650 ng/ml were found in 20/22 (91%) patients with GI malignancies, 13/18 (72%) patients with breast cancer, and 15/17 (88%) with lung cancer. Mean TSP levels of GI, breast, and lung cancer patients were 3, 2, and 3 fold greater than controls, respectively. Increased blood TSP levels in patients were not due to increased levels of platelets since both control and patient groups had platelet counts within the normal range. These results suggest that TSP may play a role in tumor cell metastasis in man and could serve as a blood marker for metastasis.


Assuntos
Biomarcadores Tumorais/sangue , Metástase Neoplásica/fisiopatologia , Neoplasias/sangue , Glicoproteínas da Membrana de Plaquetas/metabolismo , Adulto , Idoso , Idoso de 80 Anos ou mais , Plaquetas/metabolismo , Humanos , Pessoa de Meia-Idade , Projetos Piloto , Glicoproteínas da Membrana de Plaquetas/fisiologia , Trombospondinas
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA