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1.
Pathologica ; 108(2): 87-88, 2016 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28195253

RESUMO

Human papillomavirus (HPV)-related head and neck squamous cell carcinomas (HNSCC) are radiosensitive tumors and have a better prognosis than the conventional keratinizing HNSCC. Despite extensive radiographic and clinical evaluation in approximately 3% to 5% of patients who present with cervical lymph node metastases, the primary tumor remains occult. The lack of a clinically identifiable primary tumor usually leads to more aggressive therapy, which can result in higher morbidity. Herein, we report a case of a patient with an occult HPV-related HNSCC, diagnosed detecting HPV in a fine needle aspiration cytology (FNAC) of metastatic laterocervical lymph nodes.


Assuntos
Biópsia por Agulha Fina , Carcinoma de Células Escamosas/virologia , DNA Viral/genética , Neoplasias de Cabeça e Pescoço/virologia , Testes de DNA para Papilomavírus Humano , Papillomavirus Humano 16/genética , Linfonodos/virologia , Infecções por Papillomavirus/virologia , Biomarcadores Tumorais/análise , Carcinoma de Células Escamosas/química , Carcinoma de Células Escamosas/secundário , Carcinoma de Células Escamosas/terapia , Inibidor p16 de Quinase Dependente de Ciclina/análise , DNA Viral/isolamento & purificação , Neoplasias de Cabeça e Pescoço/química , Neoplasias de Cabeça e Pescoço/patologia , Neoplasias de Cabeça e Pescoço/terapia , Papillomavirus Humano 16/isolamento & purificação , Humanos , Imuno-Histoquímica , Linfonodos/patologia , Metástase Linfática , Masculino , Pessoa de Meia-Idade , Infecções por Papillomavirus/patologia , Infecções por Papillomavirus/terapia , Valor Preditivo dos Testes , Carcinoma de Células Escamosas de Cabeça e Pescoço
2.
Pathologica ; 106(4): 342-4, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25845052

RESUMO

INTRODUCTION: Adenoid cystic carcinoma is a malignant neoplasm most commonly originating in the salivary glands. Its occurrence elsewhere is rare and its metastasis to the thyroid gland has been described only once. CASE REPORT: We describe the case of a 66-year-old man who presented for a swelling in the midline neck of six months duration. A solitary palpable nodule was identified in the isthmic region of the thyroid. Fine needle aspiration of the nodule revealed high cellularity, a partial microfollicle-like pattern and the presence of small hyaline globules. The neoplastic population was composed of monomorphic cells with basaloid appearance. Thyroid primitivity was excluded on the basis of the negativity for TTF1 and thyroglobulin. As the patient referred an ulcerative lesion of the inferior lip, fine needle aspiration cytology of the lesion was performed, yielding a diagnosis of adenoid cystic carcinoma. CONCLUSION: The present case highlights the need to be aware of possible metastatic thyroid localisation of adenoid cystic carcinoma also originating in minor salivary glands of the oral cavity. This is a very rare event, but it should be taken into consideration and clinical and cytological findings must be carefully examined.


Assuntos
Carcinoma Adenoide Cístico/patologia , Neoplasias das Glândulas Salivares/patologia , Glândula Tireoide/patologia , Idoso , Biópsia por Agulha Fina/métodos , Carcinoma Adenoide Cístico/diagnóstico , Carcinoma Adenoide Cístico/secundário , Citodiagnóstico/métodos , Humanos , Masculino , Neoplasias das Glândulas Salivares/diagnóstico
3.
Histopathology ; 31(3): 231-6, 1997 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-9354893

RESUMO

AIMS: Thyroid carcinoma is an extracolonic manifestation that is present in about 1% to 2% of patients with familial adenomatous polyposis (FAP). Less than 100 cases have been reported in detail. We have investigated the suggestion that FAP associated thyroid carcinoma is significantly different morphologically from both papillary and follicular types and can be considered as a separate entity. METHODS AND RESULTS: Specimens from three patients with FAP associated thyroid tumours, all but one having single nodules, have been analysed. All three patients belonged to an extended kindred (23 siblings in four generations) who had genetic analysis and intensive screening for thyroid nodules. Seven patients had the same APC mutation at codon 1061. Pathological examination revealed a typical papillary carcinoma, encapsulated variant, in all patients, with follicular areas in one case. All thyroid specimens, in addition to histological and immunohistological examinations, were also specifically studied for activation of the RET-PTC oncogene, that seems to be restricted to papillary thyroid carcinoma. Two of the three patients had RET-PTC activation (PTC1 isoform). CONCLUSIONS: The findings suggest that the tumours were certainly papillary, at least in the present kindred. Further studies in different families are required for a better understanding of this peculiar tumour and of its biological behaviour.


Assuntos
Polipose Adenomatosa do Colo/complicações , Polipose Adenomatosa do Colo/patologia , Neoplasias da Glândula Tireoide/complicações , Neoplasias da Glândula Tireoide/patologia , Polipose Adenomatosa do Colo/genética , Adolescente , Adulto , Biomarcadores/análise , Biópsia por Agulha , Feminino , Humanos , Imuno-Histoquímica , Masculino , Mutação , Proteínas de Fusão Oncogênica/genética , Proteínas de Fusão Oncogênica/metabolismo , Proteínas Tirosina Quinases , Doenças Retinianas/complicações , Doenças Retinianas/patologia , Tireoglobulina/análise , Neoplasias da Glândula Tireoide/química , Neoplasias da Glândula Tireoide/genética
4.
J Pathol ; 182(2): 145-50, 1997 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-9274523

RESUMO

This study asks whether the known genotypic heterogeneity within and between endemic or sporadic Burkitt's lymphomas (eBLs and sBLs, n = 10 each), and Burkitt-like lymphomas (BLLs, n-12), is reflected in divergent cytokinetics and related immunophenotypes. There was strong evidence that eBL and BLL grow markedly faster than sBL, as shown by differences in mitotic and apoptotic indices. Furthermore, in BLL, the median percentage of neoplastic cells immunoreactive for the bcl-2 protein was much higher than that observed in eBL and sBL. The reverse was true for the median fraction of cells containing c-myc protein. In eBL and sBL, the median fraction of bcl-6 protein-positive cells reached values above 50 per cent, while cells of 8/12 BLLs did not contain detectable amounts of this protein. This observation indicates that in this respect, eBL and sBL resemble normal germinal centres of lymphatic tissue much more than do BLL. Evidence for infection of neoplastic cells by the Epstein-Barr virus (EBV) was observed in 9/10 cases of eBL and in 3/10 of sBL, but not in BLL. EBV-positive lymphomas were associated with distinctly lower apoptotic indices and smaller median percentages of bcl-6-positive cells than EBV-negative tumours.


Assuntos
Linfoma de Burkitt/patologia , Adolescente , Adulto , Linfoma de Burkitt/virologia , Ciclo Celular , Criança , DNA Viral/análise , Proteínas de Ligação a DNA/metabolismo , Feminino , HIV , Infecções por HIV/patologia , Herpesvirus Humano 4 , Humanos , Imuno-Histoquímica , Linfoma/patologia , Linfoma/virologia , Linfoma Relacionado a AIDS/patologia , Masculino , Pessoa de Meia-Idade , Fenótipo , Proteínas/metabolismo , Proteínas Proto-Oncogênicas/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Proteínas Proto-Oncogênicas c-bcl-6 , Fator 2 Associado a Receptor de TNF , Fatores de Transcrição/metabolismo , Proteína Supressora de Tumor p53/metabolismo
5.
Biopharm Drug Dispos ; 18(2): 165-84, 1997 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-9099452

RESUMO

The toxicology and toxicokinetics of a selegiline transdermal system (STS) were evaluated in a 3 month dog study of daily 24 h applications of placebo 4, 8, or 12 STSs in 32 male and 32 female beagle dogs. Each STS delivered approximately 5 mg selegiline over 24 h. No drug-related signs of toxicity were noted in any group with respect to clinical observations, dermal effects, body weight, food consumption, hematology, urinalysis data, or ophthalmoscopic or electrocardiographic examinations. Clinical chemistry data revealed no consistent adverse effects except for an increase in alanine aminotransferase in dogs receiving 8 and 12 STSs. Histological evaluation of tissues revealed the presence of pigment in the Kupffer cells of dogs treated with 8 and 12 STSs. There were no pathology findings suggestive of hemolysis or cholestasis. The no-effect level (NOEL) was 4 STSs (2.9 mg kg-1 d-1). There were no degenerative or life-threatening toxic effects up to 12 STSs (8.5 mg kg-1 d-1). Gender-related differences in steady-state plasma levels were not observed. Steady-state plasma concentrations were similar to maximum plasma concentrations obtained in single-dose studies, suggesting that drug accumulation was not evident. Simulation of systemic exposure following oral administration of 16.8 mg kg-1 d-1 from previous toxicology studies indicated that selegiline exposure following 12 STSs is sixfold greater while N-desmethylselegiline, L-amphetamine, and L-methamphetamine exposure is 0.5, 0.15, and 0.14 times the exposure in the oral study. The threefold difference in NOEL between oral and transdermal studies in the dog (0.8 versus 2.9 mg kg-1 d-1) is probably related to greater L-amphetamine and L-methamphetamine exposure following oral administration. The reduction in metabolite formation, relative exposure of selegiline in the dog at the NOEL compared to oral toxicology studies, and margin of safety provided, given that the expected clinical dose is less than the dosage of oral Eldepryl (0.15 mg kg-1 d-1), documents the safety of the selegiline drug substance and indicates that additional toxicologic findings with the STS may not be expected.


Assuntos
Antiparkinsonianos/toxicidade , Inibidores da Monoaminoxidase/toxicidade , Selegilina/toxicidade , Administração Cutânea , Animais , Antiparkinsonianos/farmacocinética , Cães , Sistemas de Liberação de Medicamentos , Avaliação Pré-Clínica de Medicamentos , Feminino , Masculino , Inibidores da Monoaminoxidase/farmacocinética , Projetos Piloto , Selegilina/farmacocinética
6.
J Clin Pharmacol ; 37(3): 238-47, 1997 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-9089426

RESUMO

Orally administered selegiline hydrochloride is a selective monoamine oxidase type B inhibitor at the recommended regimen of 10 mg/day, but it loses selectivity at higher doses. In bypassing first-pass metabolism, a 24-hour application of transdermally administered selegiline (7.8 mg/24 hr) yields fifty times greater systemic exposure than is provided by single oral doses. The current study was designed to demonstrate that, similar to the oral regimen, transdermally administered selegiline is devoid of the pressor effects associated with tyramine and classic monoamine oxidase type A inhibitors. A single-blind, staggered, parallel-group study of pressor response to tyramine during a single 24-hour application of one-quarter, one-half, or one selegiline transdermal system relative to baseline (drug-free) response to tyramine was conducted in three groups, each with five healthy male volunteers. The end point of pressor response was declared if a participant's systolic blood pressure rose by > 30 mmHg, heart rate decreased by > 25 bpm with an associated > 20-mmHg rise in systolic blood pressure, or a clinically significant change was observed in the electrocardiogram. Doses up to 600 mg were administered during the baseline phase and up to 200 mg during the active-treatment phase. Participants received escalating tyramine doses every 4 hours until the maximum or threshold dose was achieved. Doses up to 200 mg were tolerated without apparent increase in sensitivity in participants receiving one-quarter, one-half, or one selegiline transdermal system. All participants completed the trial, and no significant adverse events were reported. Monoamine oxidase type B inhibition was complete (100%) by 12 hours after initial application in all treatment groups while plasma levels of 3-methoxy-4-hydroxyphenylglycol (MHPG) after 24-hour application were unaffected relative to baseline. These results suggest that systemic selegiline levels may not predict the propensity for a hypertensive crisis associated with presumed nonselective doses and that the avoidance of peripheral monoamine oxidase type A inhibition in the gut via the selegiline transdermal system may provide a safe vehicle for administering selegiline at plasma levels beyond that which can be safely obtained after oral administration. These findings will need to be confirmed in a long-term dose setting.


Assuntos
Pressão Sanguínea/efeitos dos fármacos , Frequência Cardíaca/efeitos dos fármacos , Inibidores da Monoaminoxidase/farmacocinética , Selegilina/farmacocinética , Tiramina/farmacocinética , Administração Cutânea , Adulto , Relação Dose-Resposta a Droga , Humanos , Masculino , Inibidores da Monoaminoxidase/administração & dosagem , Inibidores da Monoaminoxidase/efeitos adversos , Selegilina/administração & dosagem , Selegilina/efeitos adversos , Método Simples-Cego , Tiramina/administração & dosagem
7.
Pharm Res ; 14(1): 50-5, 1997 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-9034220

RESUMO

PURPOSE: A Selegiline Transdermal System (STS) is under development for indications which may not be optimally or safely treated with oral selegiline. Studies were conducted to evaluate the in vitro penetration and skin metabolism of selegiline in order to better understand the toxicological findings and the observed plasma levels of selegiline and its metabolites in animals and man. METHODS: In vitro penetration studies were conducted in four different species (male hairless mice, male and female rats, female dog and male Micropig) and compared to human skin. In another study, viable human skin was used to estimate the extent of metabolism of selegiline by human skin using Franz diffusion cells. RESULTS: Results indicated that female dog and male Micropig skin were reasonable animal models for 24 hour in vitro selegiline penetration through human skin. Penetration of selegiline through rat skin and hairless mouse skin was 2-fold and 3-fold higher than through human skin, respectively. Metabolism was negligible in human skin. Selegiline metabolites (L-methamphetamine and N-desmethylselegiline but not L-amphetamine) were detected at all time points but the extent of selegiline metabolism was negligible. The cumulative 24 hour in vitro selegiline permeation from a 1.83 mg/cm2 STS through human skin was 5.0 mg. This was similar to the in vivo permeation in humans as assessed by residual patch analysis. CONCLUSIONS: The similarity of dog and human skin permeation results support the use of the dog as a species for evaluating the toxicology of transdermally-administered selegiline. Selegiline is not metabolized cutaneously and hence the metabolic profile following STS administration is likely due to hepatic metabolism only.


Assuntos
Inibidores da Monoaminoxidase/metabolismo , Selegilina/metabolismo , Absorção Cutânea , Pele/metabolismo , Animais , Cães , Feminino , Humanos , Masculino , Camundongos , Camundongos Pelados , Ratos , Especificidade da Espécie , Suínos , Porco Miniatura
8.
Am J Ther ; 3(10): 688-98, 1996 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11862224

RESUMO

This open-label, two-phase cross-over study compared the safety and pharmacokinetics of transdermally administered selegiline and orally administered selegiline hydrochloride in elderly men and women (n = 6/gender). Single oral doses of 10 mg selegiline hydrochloride and single 1/2 and 1 selegiline transdermal system (STS) (delivering similar3.4 and 6.3 mg over 24 h) administered topically were safe and well tolerated in all subjects. Plasma concentrations of selegiline (SEL) and its N-desmethylselegiline (DMS), L-amphetamine (AMP), and L-methamphetamine (MET) metabolites were measured using an HPLC/MS/MS method with lower quantitation limits of 10, 50, 200, and 200 pg/mL, respectively. No significant gender-related differences were observed following single 10-mg oral doses of selegiline hydrochloride or single 24-h applications of 1/2 and 1 STS to elderly males and females. The low level of dermal irritation as assessed by erythema and edema rating scales suggests that the STS was similar to Band-Aid (Johnson & Johnson, Skillman, NJ) controls. The transdermal administration of SEL bypasses the first-pass metabolism, that is significant after oral administration (first-pass extraction >90%). Peak plasma levels of 1.19, 23.22, 4.78, and 14.08 ng/mL were observed for SEL, DMS, AMP, and MET after a single 10-mg oral dose to the elderly. By contrast, peak plasma levels of 2.10, 0.85, 1.06, and 2.71 ng/mL were observed for SEL, DMS, AMP, and MET after a single 24-h application of 1 STS. Comparison of dose-corrected areas under the curve (AUCs) (made under the assumption of linear pharmacokinetics) indicate the SEL exposure after transdermal application was more than 50-fold greater than that obtained orally. This increase in systemic SEL exposure at the expense of metabolite formation that is reduced to <70% of that obtained orally for N-DMS, L-AMP, and L-MET is hypothesized to be of therapeutic value in patients with a variety of neurodegenerative and psychiatric disorders.

9.
Int J Cancer ; 65(6): 781-4, 1996 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-8631592

RESUMO

The Epstein-Barr Virus (EBV) has been implicated in the pathogenesis of Hodgkin's disease (HD). However, the association of EBV with this disease varies greatly from series to series and from country to country. Epidemiological studies have shown differences in HD occurring in different parts of the world. In particular, it has been reported that HD in developing countries differs from HD in Western countries in terms of epidemiological, pathological and clinical characteristics. These discrepancies among populations suggest an interaction with environmental factors and a direct role of different etiological agents. At present, there are no data on the frequency of association of EBV with HD in equatorial Africa. In this study, a large series of HD cases have been collected at the University of Nairobi, Kenya, and at the Universities of Bologna and Siena, Italy. The cases have been reviewed and classified according to the REAL Classification and the presence of EBV has been assessed by in situ hybridization (ISH). A statistical difference in EBV expression was found between HD from Kenya and HD from Italy. EBV-positive neoplastic cells were detected in 92% of Kenyan cases, whereas only 48% of Italian cases showed EBER1/2 positivity in the neoplastic cells. Our results suggest that, in Kenya, EBV plays a more direct role in the pathogenesis of HD, as it does for endemic Burkitt lymphoma.


Assuntos
Infecções por Herpesviridae/epidemiologia , Herpesvirus Humano 4 , Doença de Hodgkin/virologia , Infecções Tumorais por Vírus/epidemiologia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Criança , Pré-Escolar , Feminino , Doença de Hodgkin/epidemiologia , Doença de Hodgkin/patologia , Humanos , Hibridização In Situ , Itália/epidemiologia , Quênia/epidemiologia , Masculino , Pessoa de Meia-Idade , Prevalência
10.
Artigo em Inglês | MEDLINE | ID: mdl-1355321

RESUMO

Coarse granularity of nuclear chromatin texture is a prominent feature of most malignant cell lines. We have chosen the abrupt transition from eu- to heterochromatic foci (high contrast gradient [CG]) as a novel parameter for coarseness. This feature was quantified using automated image analysis of single nuclei in smears stained by the May-Grünwald-Giemsa technique. The principle of this approach consists of eliminating, with the help of subtraction between two image lowpass filters, the small grey level differences among pixels, so that only high CG values are retained on the digitized image. The sum of these distinctive microareas is then taken as a fraction of the area of the peripherally eroded nucleus, and this ratio is designated as contrast gradient index (CGI) per nucleus. This method was tested on fine needle aspirates from 11 patients with benign breast disease (BBD) and 14 with mammary carcinoma (CA). For each specimen, 60 nuclei were analyzed, with a measuring time per nucleus of about 1 min. A high significant distinction between epithelial cell populations in BBD and CA, respectively, was obtained by variance analysis of all CGIs per nucleus (p = 2 x 10(-18). The median and the mean values of CGI per specimen were the next best discriminators, followed by the modes and the standard deviation of CGI per specimen. The percentage of nuclei per specimen with CGI values of greater than 12 was also significantly greater in CA than in BBD.


Assuntos
Neoplasias da Mama/patologia , Cromatina/patologia , Processamento de Imagem Assistida por Computador/métodos , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Biópsia por Agulha , Epitélio/patologia , Estudos de Viabilidade , Feminino , Humanos , Pessoa de Meia-Idade
11.
Radiol Med ; 77(4): 369-72, 1989 Apr.
Artigo em Italiano | MEDLINE | ID: mdl-2657880

RESUMO

The sonographic detection of adrenal masses in patients with neoplasms, especially neoplasms of the lung, can be related to the presence of both metastases and adenomas. In order to assess the benign/malignant nature of such lesions, the adrenal glands of 43 patients with neoplasms (36 of them lung cancers) were studied with sonography (US) and fine needle aspiration biopsy (FNAB): in all, 58 masses were seen (28 monolateral and 15 bilateral). Six lesions (13%) presented with cytological features of benignancy, and on US they appeared as hypoechoic (as compared to the liver), round masses, with regular margins, ranging in size from 1.2 cm to 3.4 cm (average: 2.6 cm). In the remaining 34 patients (80%), cellular material with features of malignancy was obtained with FNAB. The US appearance of these metastases was heterogeneous, with the same echogenicity as the liver, and average size greater than 3 cm. On the basis of our data, the limit of 3 cm (if we consider the average dimension), corresponds to the threshold of benignancy, as well as the monolateral and hypoechoic appearance of the lesion. To sum up, the use of FNAB should be limited to those lesions which present with typical adenomatous features and for borderline lesions, while the diagnosis of metastasis is sufficiently accurate (p less than 0.001) in case of bilateral or isoechoic lesions greater than 3 cm.


Assuntos
Adenoma/diagnóstico , Adenoma/secundário , Neoplasias das Glândulas Suprarrenais/diagnóstico , Neoplasias das Glândulas Suprarrenais/secundário , Ultrassonografia , Adenoma/patologia , Neoplasias das Glândulas Suprarrenais/patologia , Glândulas Suprarrenais/patologia , Biópsia por Agulha , Diagnóstico Diferencial , Seguimentos , Humanos , Estadiamento de Neoplasias
12.
J Pharm Sci ; 71(9): 1034-8, 1982 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-7131270

RESUMO

Two human bioavailability studies were conducted to assess the in vivo performances of recently marketed 200-, 300-, and 400-mg ibuprofen capsules relative to the innovator's 300- and 400-mg tablets when administered as single oral 300- or 400-mg doses. An ibuprofen oral solution was also administered in each trial. Within each study, the products were equivalent to each other and to the oral solution with respect to the extent of ibuprofen absorption. Absorption rates, however, differed markedly among the products studied. Ibuprofen was more slowly absorbed from the 300- and 400-mg capsules than from the respective strength tablets. The 200-mg capsule exhibited an absorption rate comparable to the 400-mg tablet but more rapid than the 400-mg capsule. It was concluded that two of the duplicator's 200-mg capsules were bioequivalent to one of the innovator's 400-mg tablet. The duplicator's 300- and 400-mg capsules were bioinequivalent to the innovator's 300- and 400-mg tablets, respectively, due to their slower rates of absorption.


Assuntos
Ibuprofeno/administração & dosagem , Adolescente , Adulto , Disponibilidade Biológica , Cápsulas , Feminino , Humanos , Ibuprofeno/metabolismo , Masculino , Modelos Biológicos , Solubilidade , Soluções , Comprimidos , Fatores de Tempo
13.
J Clin Pharmacol ; 22(7): 321-5, 1982 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-7107981

RESUMO

The objective of this study was to compare the pharmacokinetic behavior of erythromycin in normal volunteers with that in subjects with alcoholic liver disease. Six normal volunteers received 500 mg erythromycin as an intravenous infusion or as two 250-mg enteric-coated tablets in a crossover fashion. The pharmacokinetics of erythromycin after intravenous administration was best described as a two-compartment model. The elimination half-life was 1.6 +/- 0.7 hours (mean +/- S.D.) after the intravenous dose and 2.0 +/- 0.7 hours after the oral dose. In patients with alcoholic liver disease the elimination half-life after oral administration of two 250-mg enteric-coated tablets was 3.2 +/- 0.5 hours, significantly different from that in normal subjects, probably due to impaired metabolism. The difference in half-life does not require dosage adjustment in this patient population. The systemic availability of erythromycin was 33.5 per cent (range 10.5 to 79.3 per cent).


Assuntos
Eritromicina/metabolismo , Cirrose Hepática Alcoólica/metabolismo , Administração Oral , Adulto , Feminino , Humanos , Injeções Intravenosas , Cinética , Masculino , Fatores de Tempo
15.
Antimicrob Agents Chemother ; 20(2): 190-6, 1981 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-7283417

RESUMO

We performed a series of six single-dose and multiple-dose studies to evaluate the effect of food on the absorption of erythromycin base and erythromycin stearate. When we used a single-dose design, we found that an unprotected erythromycin base preparation was absorbed extensively if a prolonged fast preceded administration of the drug. A shorter faster period (as occurs in clinical settings) dramatically reduced the absorption of unprotected base; however, film-coated tablets seemed to be as well protected as and were absorbed more rapidly than enteric-coated tablets when they were evaluated by single-dose testing procedures. In contrast, when a commercially available film-coated preparation of erythromycin base was evaluated in multidose fashion between meals (fasting), the drug was about 25% less well absorbed than commercially available enteric-coated base tablets. Finally, when commercially available film-coated erythromycin base and stearate formulations were administered with meals, both film-coated preparations were 43 to 59% less well absorbed than the enteric-coated base formulation. Furthermore, the enteric-coated base formulation performed equally well when administered either every 6 h between meals (fasting) or four times a day (immediately after meals and at bedtime). These studies document the need for multidose bioavailability techniques when the bioavailabilities of acid-labile drugs are evaluated.


Assuntos
Eritromicina/análogos & derivados , Eritromicina/metabolismo , Alimentos , Absorção Intestinal , Adulto , Eritromicina/administração & dosagem , Jejum , Humanos , Cinética , Projetos de Pesquisa , Comprimidos , Comprimidos com Revestimento Entérico
16.
Res Commun Chem Pathol Pharmacol ; 32(3): 387-405, 1981 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-7268190

RESUMO

The simplest three pharmacokinetic models which apply in cases of reversible metabolism are described. Area under the curve (AUC) relationships are described which allow one to make a choice of which one of the three models may apply in a particular case. Expressions for clearances and other pharmacokinetic parameters are given. It is shown that biexponential time courses are expected after bolus intravenous administration although distribution is not involved in the models. In some cases dose/AUC or infusion rate/steady-state concentration yield simple clearances, while in other cases they are complex. AUC data obtained following oral administration of 5 mg doses of prednisone and prednisolone to 16 normal volunteers were analyzed with the new concepts and one of the models was found to apply. This new interpretation of such data results in some significant changes from application of classical pharmacokinetics.


Assuntos
Prednisolona/metabolismo , Prednisona/metabolismo , Adolescente , Adulto , Biotransformação , Humanos , Injeções Intravenosas , Cinética , Pessoa de Meia-Idade , Modelos Biológicos , Fatores de Tempo
17.
J Clin Pharmacol ; 20(7): 428-36, 1980 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-7430411

RESUMO

The pharmacokinetic and biopharmaceutic profiles of a single dose of oral cortisone acetate were developed for 23 healthy normal adult volunteers using cortisone and cortisol plasma concentration data. Cortisone acetate was rapidly absorbed and converted to the therapeutic moiety cortisol. There was a linear increase in plasma concentrations and, therefore, areas under plasma concentration-time curves with increasing doses of 5, 10, and 25 mg. Twenty-five-mg doses given as 1 x 25 mg or 5 x 5 mg were found to be bioequivalent. The increased efficacy of oral over intramuscular cortisone acetate can be attributed to the increased conversion to cortisol as a result of first-pass metabolism following oral dosing.


Assuntos
Cortisona/sangue , Hidrocortisona/sangue , Administração Oral , Adolescente , Adulto , Cortisona/administração & dosagem , Dexametasona/farmacologia , Relação Dose-Resposta a Droga , Humanos , Injeções Intramusculares , Cinética , Pessoa de Meia-Idade , Fatores de Tempo
18.
J Clin Pharmacol ; 20(7): 437-43, 1980 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-7430412

RESUMO

A randomized crossover study in 16 healthy volunteers given multiple doses of erythromycin base enteric-coated tablets or erythromycin estolate capsules revealed essentially no difference in the resultant plasma concentration of bioactive erythromycin. This similarity in bioactivity persisted despite the fact that total eryghromycin levels (bioactive erythromycin base plus bioinactive erythromycin propionate) were at least three times higher after administration of the estolate than after administration of the base.


Assuntos
Estolato de Eritromicina/metabolismo , Eritromicina/análogos & derivados , Eritromicina/metabolismo , Adulto , Disponibilidade Biológica , Cápsulas , Eritromicina/administração & dosagem , Estolato de Eritromicina/administração & dosagem , Feminino , Humanos , Masculino , Distribuição Aleatória , Comprimidos com Revestimento Entérico , Fatores de Tempo
19.
J Clin Pharmacol ; 19(11-12): 721-5, 1979.
Artigo em Inglês | MEDLINE | ID: mdl-536468

RESUMO

Since it has been reported by several authors that colestipol HCl and clofibrate have an additive effect in lowering serum cholesterol levels, it was felt advisable to evaluate the blood levels of clofibrate when given simultaneously with colestipol HCl to see whether there was any evidence for drug interaction between the two products that might dictate a need for separation of their administration time. After concomitant single-dose administration, the serum p-chlorophenoxyisobutyric acid levels, bioavailability parameters, and pharmacokinetic parameters investigated provided no evidence for an interaction and suggested that colestipol and clofibrate can be administered concomitantly or at separated in tervals according to whichever dosage regimen is deemed advisable by the physician.


Assuntos
Clofibrato/metabolismo , Colestipol/farmacologia , Poliaminas/farmacologia , Adulto , Disponibilidade Biológica , Clofibrato/sangue , Interações Medicamentosas , Humanos , Absorção Intestinal , Cinética , Masculino , Fatores de Tempo
20.
J Pharm Sci ; 68(10): 1312-6, 1979 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-512868

RESUMO

The variability and relative bioavailability of methylprednisolone tablets were evaluated utilizing a double Latin square crossover design in which each of 20 subjects was given four of five treatments. Three different lots of methylprednisolone tablets exhibited virtually identical absorption, with similar ranges and coefficients of variation of some selected bioavailability parameters indicative of lot-to-lot uniformity in bioavailability. Within-lot and between-lot uniformities in bioavailability also were similar, suggesting that the observed variability in serum methylprednisolone levels was not due to manufacturing process variables. With respect to intra-versus intersubject variability, no differences were found for the absorption rate or terminal half-life. In contrast, between-subject variability associated with extent of absorption was greater than that within subjects. Relative to an aqueous suspension, methylprednisolone tablets were fully bioavailable.


Assuntos
Metilprednisolona/metabolismo , Adulto , Análise de Variância , Disponibilidade Biológica , Meia-Vida , Humanos , Masculino , Metilprednisolona/administração & dosagem , Estatística como Assunto , Fatores de Tempo
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