Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 6 de 6
Filtrar
Mais filtros

Base de dados
Tipo de documento
Intervalo de ano de publicação
1.
Otolaryngol Head Neck Surg ; 166(6): 1161-1165, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35133915

RESUMO

The field of otolaryngology has one of the lowest rates of racial and ethnic diversity. An anonymous survey was distributed to members of the Student National Medical Association at different medical schools to identify factors that may contribute to this disparity. Responses were received from 104 students at 36 allopathic medical schools. Most respondents identified as black (86.5%). One-third of students (34.6%) noted that they were discouraged from pursuing otolaryngology due to lack of mentorship, and among these students, most noted that they lack mentors of the same race (75%). One-fourth of respondents (25%) indicated that they lack a home otolaryngology program. The most common reasons for participants' disinterest in otolaryngology included competitiveness, inadequate exposure, research, and the high board scores needed to match. This hypothesis-generating, proof-of-concept study highlights potential barriers that may discourage underrepresented medical students from pursuing a career in otolaryngology.


Assuntos
Internato e Residência , Otolaringologia , Estudantes de Medicina , Humanos , Mentores , Otolaringologia/educação , Inquéritos e Questionários
2.
Head Neck ; 44(2): 325-331, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-34773312

RESUMO

BACKGROUND: Higher body mass index (BMI) may have a protective effect on survival in patients with head and neck cancer. The aim of this study was to determine the effect of BMI on overall survival (OS) in veterans with head and neck squamous cell carcinoma (HNSCC). METHODS: A cohort of 702 patients diagnosed with HNSCC between 1995 and 2019 were identified at the Washington DC Veterans Affairs Medical Center, and 342 patients were included for analysis. Records were queried for clinical-demographic data, BMI, and outcomes. RESULTS: HNSCC patients categorized as overweight or obese at time of diagnosis had a lower 3-year risk of death (p = 0.033) and improved OS (p < 0.001) compared to patients who were underweight or normal weight. The majority of locoregional recurrences occurred in patients with low or normal pretreatment BMI. CONCLUSIONS: Higher BMI at diagnosis may have a protective effect on OS in veterans with HNSCC.


Assuntos
Neoplasias de Cabeça e Pescoço , Recidiva Local de Neoplasia , Índice de Massa Corporal , Neoplasias de Cabeça e Pescoço/terapia , Humanos , Obesidade/complicações , Obesidade/epidemiologia , Prognóstico , Carcinoma de Células Escamosas de Cabeça e Pescoço
3.
J Pharm Sci ; 69(4): 451-4, 1980 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-7373543

RESUMO

A novel method for the synthesis of methyl dialkylmalonuric esters was developed using the base-catalyzed ring opening of an isopropylidene malonic ester with urea as the key step. The rates of cyclization of these malonuric esters to the corresponding barbituric acids then were studied at buffer concentrations ranging from 0.01 to 1.00 M. The reaction was shown to be general base catalyzed, and the reaction rate was found to be subject to a deuterium isotope effect, kH2O/kD2O=1.3. The thermodynamic activation parameters also were determined. A three-step mechanism for the conversion of malonuric esters to barbituric acids was proposed; it involved a rapid cyclization step, followed by proton removal by a general base catalyst and a rate-determining collapse of the resulting tetrahedral intermediate aided by a general acid.


Assuntos
Barbitúricos/síntese química , Malonatos , Ureia , Ciclização , Cinética , Termodinâmica
4.
J Neural Transm ; 44(3): 197-220, 1979.
Artigo em Inglês | MEDLINE | ID: mdl-571457

RESUMO

An antigonadotropic substance was partially purified from aqueous extracts of bovine pineal glands by methods of gel filtration, ultrafiltration and ion exchange chromatography. Two biological tests, viz. inhibition of compensatory ovarian hypertrophy and reduction of ventral prostate weight, were used to guide the purification. The partially purified antigonadotropin was characterized chemically using techniques of UV and fluorescence spectrometry, thin layer and paper chromatography, paper electrophoresis and amino acid analysis. The results reveal a diversity of ninhydrin-positive components present in the preparations, including free and peptide-bound amino acids, as well as other unidentified components, but not including any of the commonly occurring indoles, indoleamines or catecholeamines. One peptide, oxidized glutathione, was identified in the most purified material containing the biologically active principle yet pure, synthetric glutathione has no antigonadotropic activity in the biological tests utilized. Although the chemical nature of the bovine pineal antigonadotropin remains in question it may be purified by the methods described. The activity is thought to reside in the extremely small, perhaps trace quantities of residues derived. It is believed that large scale, preparative studies will be required for structural determination.


Assuntos
Gonadotropinas/antagonistas & inibidores , Glândula Pineal/análise , Aminoácidos/análise , Animais , Bioensaio , Bovinos , Cromatografia em Papel , Eletroforese em Papel , Feminino , Masculino , Camundongos , Tamanho do Órgão/efeitos dos fármacos , Ovário/efeitos dos fármacos , Próstata/efeitos dos fármacos , Espectrometria de Fluorescência , Espectrofotometria Ultravioleta
5.
J Neural Transm ; 42(4): 275-92, 1978.
Artigo em Inglês | MEDLINE | ID: mdl-681923

RESUMO

Acetic acid extracts of bovine pineals and cerebral cortex were separated on Sephadex G-25 columns. Subsequently two low molecular weight fractions, F2 and F3, were ultrafiltered through the membranes UM2 and UM05. The UM05 residues were gel filtered on Sephadex G-15 columns or chromatographed on Dowex W50-X4 columns. Fractions from these columns were tested and those which showed COH-inhibiting activity were separated by preparative paper chromatography in different solvents. The absorption spectra of those fractions were recorded and tested for COH-inhibiting activity were separated by preparative paper chromatography in different solvents. The absorption spectra of those fractions were recorded and tested for COH-inhibition. By these methods, a COH-inhibitor was localized in three different solvents. Some active paper chromatography fractions were studied in high pressure, reverse phase, liquid chromatography. This latter method showed that the active fractions obtained by paper chromatography contain several orthophthlaldehyde (OPT) positive compounds. Key words: acetic acid, bovine pineal extracts, compensatory ovarian hypertrophy (COH), paper chromatography, high pressure, reverse phase, liquid chromatography.


Assuntos
Cromatografia por Troca Iônica , Cromatografia em Papel/métodos , Ovário/fisiologia , Glândula Pineal/análise , Acetatos , Aminoácidos/análise , Animais , Castração , Bovinos , Cromatografia em Gel , Cromatografia Líquida de Alta Pressão , Feminino , Camundongos
6.
J Neural Transm ; 45(1): 43-61, 1979.
Artigo em Inglês | MEDLINE | ID: mdl-469521

RESUMO

Bovine pineal glands were extracted according to the methods reported by Bensinger et al. (1973) and Cheesman and Fariss (1970). Isobutanol soluble COH-inhibiting activity was further separated by chromatography on Sephadex G-15 and paper chromatography. With the Bensinger method, different active pineal fractions were obtained from Sephadex G-15 columns. Certain of those fractions were further separated by paper chromatography in butanol : acetic acid : water (4 : 1 : 1) and the COH-inhibitor was localized. The pineal COH-inhibitor could also be localized by high pressure, reverse phase liquid chromatography. More COH-inhibiting activity was extracted with the Bensinger method than with aqueous and acetic acid extraction methods used earlier by us. The Cheesman extraction method for arginine vasotocin gave less regular results in our hands than the Bensinger extraction method.


Assuntos
Gonadotropinas/antagonistas & inibidores , Ovário/fisiologia , Glândula Pineal/análise , Animais , Butanóis , Bovinos , Cromatografia em Gel , Cromatografia Líquida , Cromatografia em Papel , Feminino , Gonadotropinas/isolamento & purificação
SELEÇÃO DE REFERÊNCIAS
Detalhe da pesquisa