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1.
Scand J Prim Health Care ; : 1-10, 2023 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-37837435

RESUMO

BACKGROUND: There are significant differences in the densities of resident specialists in gynaecology (RSGs) in various regions of Denmark. It is unclear whether this disparity affects gynaecological patients' experience of the referral process and whether it differs in terms of their socioeconomic status (SES). OBJECTIVE: To examine gynaecological patients' experiences of the referral process to an RSG concerning RSG density and patients' SES. DESIGN: Cross-sectional questionnaire and registry-based study. SETTING: In Denmark, general practitioners (GPs) serve as gatekeepers of secondary care and are responsible for referrals to resident specialists as well as inpatient and outpatient hospital care. SUBJECTS: A total of 2917 patients who consulted an RSG participated in this study. MAIN OUTCOME MEASUREMENTS: Patients' experiences of referral to an RSG, waiting times, involvement, and how they experienced the referral process. RESULTS: Patients who lived in the highest density RSG region were referred to an RSG more promptly after the onset of symptoms, had to visit their GP less frequently to obtain a referral to the RSG, and rarely received a gynaecological examination by their GP compared with those living in regions with lower RSG densities. Moreover, their waiting times were shorter, and more often, the patients themselves proposed to be referred to an RSG. The findings show that RSG density had a greater impact on women's experiences than SES. CONCLUSION: To allow equal access to specialist care, RSG density must be equal across all regions in the country.

2.
Scand J Prim Health Care ; 41(1): 52-60, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36633427

RESUMO

BACKGROUND: There are large differences in the density of Resident Specialists in Gynaecology (RSG) in the various regions of Denmark. It is unknown if this inequality affects the General Practitioner (GP) referral patterns of gynaecological patients. OBJECTIVE: To investigate the GP referral patterns of gynaecological patients to the RSG or to the Hospital/Outpatient Clinic (HOC) in specific situations according to the regional density of RSGs. Moreover, to examine whether GPs prefer to refer to the HOC or to the RSG, or whether they were treated by the GP depending on the density of RSGs, specifically, in six benign gynaecological diagnoses. DESIGN: A cross-sectional questionnaire survey. SETTING: In Denmark, GPs serve as gatekeepers to secondary care, being responsible for referrals to resident specialists and in- and outpatient hospital care. SUBJECTS: Five hundred Danish GPs were randomly selected and invited to take part in the questionnaire study. Main outcome measurements: Referral patterns: Own treatment, RSG, or HOC. RESULTS: GPs prefer to refer their gynaecologic patients to RSGs rather than to HOCs. In addition, the study shows the higher the density of RSGs, the more gynaecological patients are referred to the RSG. This also applies to the six diagnoses examined. CONCLUSION: To allow patients' equal access to specialist care, the density of RSGs must be equal all over the country.


Assuntos
Clínicos Gerais , Ginecologia , Humanos , Estudos Transversais , Encaminhamento e Consulta , Dinamarca
3.
J Chem Inf Model ; 55(7): 1316-22, 2015 Jul 27.
Artigo em Inglês | MEDLINE | ID: mdl-26099013

RESUMO

The statistical metrics used to characterize the external predictivity of a model, i.e., how well it predicts the properties of an independent test set, have proliferated over the past decade. This paper clarifies some apparent confusion over the use of the coefficient of determination, R(2), as a measure of model fit and predictive power in QSAR and QSPR modeling. R(2) (or r(2)) has been used in various contexts in the literature in conjunction with training and test data for both ordinary linear regression and regression through the origin as well as with linear and nonlinear regression models. We analyze the widely adopted model fit criteria suggested by Golbraikh and Tropsha ( J. Mol. Graphics Modell. 2002 , 20 , 269 - 276 ) in a strict statistical manner. Shortcomings in these criteria are identified, and a clearer and simpler alternative method to characterize model predictivity is provided. The intent is not to repeat the well-documented arguments for model validation using test data but rather to guide the application of R(2) as a model fit statistic. Examples are used to illustrate both correct and incorrect uses of R(2). Reporting the root-mean-square error or equivalent measures of dispersion, which are typically of more practical importance than R(2), is also encouraged, and important challenges in addressing the needs of different categories of users such as computational chemists, experimental scientists, and regulatory decision support specialists are outlined.


Assuntos
Relação Quantitativa Estrutura-Atividade , Estatística como Assunto/métodos , Análise de Regressão
4.
J Pediatr Orthop B ; 21(2): 150-4, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-22139142

RESUMO

Hereditary multiple exostoses (HME) is a commonly inherited musculoskeletal condition and is associated with a diminished stature. We demonstrated that adults with HME were significantly shorter when compared with a control group (P<0.001); preadolescents, however, were significantly taller than predicted (P=0.01). This was reflected by their height centile; 58% of the adults were under the 25th centile, whereas 53% of the preadolescence group were above the 75th centile. Stature was more severely affected in patients with an EXT1 mutation (P=0.008). This study illustrates a novel age-related growth pattern associated with HME, which is also affected by genotype.


Assuntos
Desenvolvimento Ósseo/fisiologia , Osso e Ossos/patologia , Nanismo/diagnóstico , Exostose Múltipla Hereditária/diagnóstico , Adolescente , Fatores Etários , Osso e Ossos/fisiopatologia , Criança , Pré-Escolar , Estudos de Coortes , Comorbidade , Nanismo/epidemiologia , Nanismo/genética , Exostose Múltipla Hereditária/epidemiologia , Exostose Múltipla Hereditária/genética , Feminino , Genótipo , Humanos , Masculino , Reino Unido/epidemiologia , Adulto Jovem
5.
Chem Commun (Camb) ; 47(45): 12295-7, 2011 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-22012242

RESUMO

Reaction of 2,6-dimesityl pyridine (L(py)) with BBr(3) leads to the spontaneous formation of the trigonal dibromoborenium cation [L(py)·BBr(2)](+)via bromide ejection. Systematic structural and computational studies, and the reactivity displayed by a closely related N-heterocyclic carbene (NHC) donor, reveal the role played by arene-borane interactions in this chemistry. [L(py)·BBr(2)](+) features a structurally characterized (albeit weak) electrostatic interaction between the borane Lewis acid and flanking arene π systems.

6.
J Med Case Rep ; 2: 9, 2008 Jan 19.
Artigo em Inglês | MEDLINE | ID: mdl-18205944

RESUMO

INTRODUCTION: Obstruction of the third part of the duodenum by the superior mesenteric artery (SMA) can occur following surgical correction of scoliosis. The condition most commonly occurs in significantly underweight patients with severe deformities during the first few days to a week following spinal surgery. CASE PRESENTATION: We present the atypical case of a patient with normal body habitus and a 50 degrees adolescent idiopathic thoracolumbar scoliosis who underwent anterior spinal arthrodesis with instrumentation and developed SMA syndrome due to progressive weight loss several weeks postoperatively. The condition manifested with recurrent vomiting, abdominal distension, marked dehydration, and severe electrolyte disorder. Prolonged nasogastric decompression and nasojejunal feeding resulted in resolution of the symptoms with no recurrence at follow-up. The spinal instrumentation was retained and a solid spinal fusion was achieved with good spinal balance in both the coronal and sagittal planes. CONCLUSION: SMA syndrome can occur much later than previously reported and with potentially life-threatening symptoms following scoliosis correction. Early recognition of the condition and institution of appropriate conservative measures is critical to prevent the development of severe complications including the risk of death.

7.
Spine (Phila Pa 1976) ; 31(19): E713-7, 2006 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-16946645

RESUMO

STUDY DESIGN: Case report. OBJECTIVE: To present a pediatric patient who underwent successful 2-stage anterior and posterior scoliosis surgery 20 months after cardiac transplantation. SUMMARY OF BACKGROUND DATA: Cardiac transplantation has increased the life expectancy in children with end-stage cardiac failure caused by congenital heart disease or cardiomyopathy. Scoliosis is commonly associated with congenital cardiac disease. Previous reports have suggested that anterior scoliosis surgery is contraindicated after heart transplantation. METHODS: We describe the case of a 13-year-old patient who underwent staged anterior and posterior spinal arthrodesis to correct a severe thoracic developmental scoliosis. RESULTS: The 2 procedures were performed 1 week apart. Following the first stage, pulmonary edema had developed, which required reintubation and administration of diuretics. Significant blood loss occurred during the posterior spinal fusion. The patient had a satisfactory correction of her scoliosis and made a good recovery. Three years after surgery, she had no complaints of her back and had a solid spinal fusion. CONCLUSIONS: Elective anterior and posterior spinal arthrodesis can be safely performed in cardiac transplant recipients with severe developmental scoliosis. This procedure can achieve optimum correction of the curvature and a successful outcome without long-term medical or technical complications.


Assuntos
Insuficiência Cardíaca/cirurgia , Transplante de Coração , Escoliose/cirurgia , Fusão Vertebral , Adolescente , Criança , Comorbidade , Feminino , Insuficiência Cardíaca/epidemiologia , Humanos , Escoliose/epidemiologia , Resultado do Tratamento
8.
Occup Med ; 16(1): 65-78, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11107225

RESUMO

The occupational health and safety issues of public school employees in large urban areas are many and complex. Crumbling school infrastructure and crowded classrooms are associated with inadequate indoor air quality, asbestos exposure, noisy environments, and enhanced transmission of communicable and infectious diseases. Poor ventilation in vocational education classrooms, duplicator rooms, kitchens, and science laboratories may also contribute to hazardous exposures. Ergonomic hazards may be responsible for increasing rates of musculoskeletal disorders. Other work-related illnesses and injuries now documented among school employees include asthma, mesothelioma, asbestos-related lung cancer, violent assault, voice disorders, and depression. Such a diverse industry with many potentially hazardous activities and conditions calls for a comprehensive research and intervention agenda.


Assuntos
Acidentes de Trabalho/estatística & dados numéricos , Exposição Ocupacional/estatística & dados numéricos , Saúde Ocupacional/estatística & dados numéricos , Instituições Acadêmicas , Humanos , Ruído Ocupacional/estatística & dados numéricos , Doenças Profissionais/epidemiologia , Gestão de Riscos , Instituições Acadêmicas/estatística & dados numéricos , Estados Unidos , Violência/estatística & dados numéricos , Recursos Humanos
9.
Toxicol Appl Pharmacol ; 161(2): 123-39, 1999 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-10581206

RESUMO

We have used polycyclic aromatic hydrocarbon (PAH) alkyne metabolism-based inhibitors to test whether CYP1B1 metabolism is linked to aryl hydrocarbon receptor (AhR) activation in mouse embryo fibroblasts (MEF). 1-ethynylpyrene (1EP) selectively inactivated CYP1B1 dimethylbenzanthracene (DMBA) metabolism in C3H10T1/2 MEFs; whereas 1-(1-propynyl)pyrene (1PP) preferentially inhibited CYP1A1 activity in Hepa-1c1c7 mouse hepatoma cells (Hepa). In each cell type >90% inhibition of DMBA metabolism after 1 h treatment with each inhibitor (0.1 microM) was progressively reversed and then increased to levels seen with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) induction (fourfold stimulation). It was found that 0.1 microM 1EP and 1PP maximally induce CYP1B1 and CYP1A1 mRNA levels in10T1/2 and Hepa cells, respectively, after 6 h. 1-Ethylpyrene (EtP), which lacks the activatable acetylene moiety, was far less effective as an inhibitor and as an inducer. AhR activation is essential for 1EP induction as evidenced by the use of AhR antagonists and AhR-deficient MEFs and absence of induction following inhibition of DMBA metabolism with carbon monoxide (CO). Inhibition of CYP1B1 was linked to enhanced AhR activation even at early stages prior to significant ligand depletion. 1EP and EtP were similarly effective in stimulating AhR nuclear translocation, though 5-10 times slower compared with TCDD, and produced no significant down-regulation of the AhR. TCDD activated AhR/Arnt complex formation with an oligonucleotide xenobiotic response element far more extensively than 1EP or EtP, even at concentrations of 1EP that increased CYP1B1 mRNA to similar levels. CO did not influence these responses to EtP, event hough CO treatment potentiated EtP induction of CYP1B1 mRNA. These differences suggest a fundamental difference between PAH/AhR and TCDD/AhR complexes where CYP1B1 metabolic activity regulates the potency, rather than the formation of the AhR/Arnt complex.


Assuntos
Hidrocarboneto de Aril Hidroxilases , Inibidores das Enzimas do Citocromo P-450 , Inibidores Enzimáticos/farmacologia , Pirenos/farmacologia , Receptores de Hidrocarboneto Arílico/metabolismo , Ácido p-Aminoipúrico/farmacologia , 9,10-Dimetil-1,2-benzantraceno/metabolismo , Animais , Western Blotting , Monóxido de Carbono/farmacologia , Técnicas de Cultura de Células , Núcleo Celular/metabolismo , Citocromo P-450 CYP1A1/metabolismo , Citocromo P-450 CYP1B1 , Embrião de Mamíferos , Indução Enzimática , Fibroblastos/efeitos dos fármacos , Fibroblastos/enzimologia , Fibroblastos/metabolismo , Ligantes , Camundongos , Microssomos/efeitos dos fármacos , Microssomos/enzimologia , Microssomos/metabolismo , Dibenzodioxinas Policloradas/farmacologia , Multimerização Proteica , RNA Mensageiro/metabolismo , Receptores de Hidrocarboneto Arílico/agonistas , Fatores de Tempo
10.
Proc Natl Acad Sci U S A ; 96(5): 1977-82, 1999 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-10051580

RESUMO

CYP1B1-null mice, created by targeted gene disruption in embryonic stem cells, were born at the expected frequency from heterozygous matings with no observable phenotype, thus establishing that CYP1B1 is not required for mouse development. CYP1B1 was not detectable in cultured embryonic fibroblast (EF) or in different tissues, such as lung, of the CYP1B1-null mouse treated with the aryl hydrocarbon receptor agonist 2,3,7,8-tetrachlorodibenzo-p-dioxin whereas the equivalent wild-type EF cells express basal and substantial inducible CYP1B1 and lung expresses inducible CYP1B1. CYP1A1 is induced to far higher levels than CYP1B1 in liver, kidney, and lung in wild-type mice and is induced to a similar extent in CYP1B1-null mice. 7,12-dimethylbenz[a]anthracene (DMBA) was toxic in wild-type EFs that express CYP1B1 but not CYP1A1. These cells effectively metabolized DMBA, consistent with CYP1B1 involvement in producing the procarcinogenic 3,4-dihydrodiol as a major metabolite, whereas CYP1B1-null EF showed no significant metabolism and were resistant to DMBA-mediated toxicity. When wild-type mice were administered high levels of DMBA intragastrically, 70% developed highly malignant lymphomas whereas only 7.5% of CYP1B1-null mice had lymphomas. Skin hyperplasia and tumors were also more frequent in wild-type mice. These results establish that CYP1B1, located exclusively at extrahepatic sites, mediates the carcinogenicity of DMBA. Surprisingly, CYP1A1, which has a high rate of DMBA metabolism in vitro, is not sufficient for this carcinogenesis, which demonstrates the importance of extrahepatic P450s in determining susceptibility to chemical carcinogens and validates the search for associations between P450 expression and cancer risk in humans.


Assuntos
Hidrocarboneto de Aril Hidroxilases , Sistema Enzimático do Citocromo P-450/genética , Regulação Enzimológica da Expressão Gênica , Predisposição Genética para Doença , Linfoma/genética , Neoplasias Experimentais/genética , 9,10-Dimetil-1,2-benzantraceno/farmacocinética , Animais , Biotransformação , Carcinógenos , Células Cultivadas , Quimera , Citocromo P-450 CYP1B1 , Embrião de Mamíferos , Feminino , Fibroblastos/enzimologia , Regulação Enzimológica da Expressão Gênica/efeitos dos fármacos , Biblioteca Genômica , Pulmão/enzimologia , Linfoma/induzido quimicamente , Camundongos , Camundongos Knockout , Neoplasias Experimentais/induzido quimicamente , Especificidade de Órgãos , Dibenzodioxinas Policloradas/farmacologia , Mapeamento por Restrição , Células-Tronco
11.
Mol Biochem Parasitol ; 98(1): 17-28, 1999 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-10029306

RESUMO

We have previously characterized a highly glycosylated membrane protein (p67) in Trypanosoma brucei spp that is apparently targeted to lysosomes in a developmentally regulated manner. Antibody to native p67 identified a partial cDNA clone from a T. b. rhodesiense expression library and RT-PCR was used to complete the sequence of the cDNA. Equal levels of p67 transcript are detected in both procyclic and bloodstream stages of the life cycle. The 2771 nt cDNA contains a 1980 nt orf encoding a 659 amino acid polypeptide (72,567 Da). Hydropathy analysis predicts a Type I membrane topology (N to C): an N-terminal signal sequence, a large hydrophilic lumenal domain with 14 N-glycosylation sites, a trans-membrane domain (19 aa), and a short (24 aa) cytoplasmic domain. Peptide microsequencing of purified p67 identified nine residues identical to the deduced amino acid sequence, confirming the identity of the cDNA and defining the signal sequence cleavage site. Antibody to p67 protein produced in E. coli recognizes the same spectrum of native p67 glycoforms as the antibody used to clone the cDNA. All features of the deduced amino acid sequence are consistent with the known properties of the native protein and suggest a structure similar to mammalian LAMPS. The cytoplasmic domain contains two putative di-leucine targeting motifs similar to those involved in lysosomal targeting in vertebrate cells. Our results suggest that a single p67 polypeptide, or a group of highly related polypeptides, is synthesized in both bloodstream and procyclic trypanosomes and that subsequent post-translational processing and lysosomal targeting is subject to stage-specific regulation.


Assuntos
Lisossomos , Glicoproteínas de Membrana/genética , Proteínas de Protozoários/genética , Trypanosoma brucei brucei/genética , Sequência de Aminoácidos , Animais , Antígenos CD/genética , Transporte Biológico , Compartimento Celular , DNA Complementar/genética , Expressão Gênica , Genes de Protozoários , Proteínas de Membrana Lisossomal , Glicoproteínas de Membrana/isolamento & purificação , Dados de Sequência Molecular , Fases de Leitura Aberta , Processamento de Proteína Pós-Traducional , Sinais Direcionadores de Proteínas/genética , Proteínas de Protozoários/isolamento & purificação , Homologia de Sequência de Aminoácidos
12.
J Cell Sci ; 111 ( Pt 22): 3311-22, 1998 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-9788873

RESUMO

The aryl-hydrocarbon receptor (AhR) is a ligand-dependent transcription factor that mediates the biological effects of 2,3,7, 8-tetrachlorodibenzo-p-dioxin (TCDD). In mouse embryo fibroblasts, TCDD activates expression of multiple genes, including CYP1B1, the predominant cytochrome P450 expressed in these cells. Here, we analyze constitutive functions of the AhR in primary mouse embryo fibroblasts (MEFs) and spontaneously immortalized MEF cell lines derived from wild-type (WT) C57BL/6 mice and also from congenic mice with a targeted disruption of the AhR gene (AhR-/-). After multiple passages, primary MEFs exhibit spontaneous differentiation, growth cessation and senescence. Eventually, colonies of immortalized MEFs arise to provide clonal lines. The senescent phase occurs much earlier for AhR-/- MEFs, while immortalization is substantially delayed. Comparison of AhR-/- and WT MEFs also indicates that constitutive AhR activity is required for basal expression of CYP1B1 and suppresses lipogenesis in subconfluent cultures. Primary WT and AhR-/- MEFs and the corresponding lines undergo adipogenesis when treated at confluence with the appropriate hormonal inducers. Addition of TCDD before or concurrent with hormonal induction suppressed PPAR gamma mRNA and adipogenesis, as measured by lipid accumulation, glycerol phosphate dehydrogenase activity and stearoyl CoA desaturase type 1 mRNA expression. This effect of TCDD treatment was absent in AhR-/- MEFs, establishing the role of AhR in hormone-induced adipogenesis. Such hormonal activation of confluent MEFs and preadipocytes results in a limited proliferative expansion followed by irreversible growth arrest. TCDD-treated MEFs undergo the mitotic expansion but fail to exit the cell cycle. In AhR-/- MEFs, there is no such effect of TCDD. These findings implicate the AhR as a constitutive inhibitor of triglyceride synthesis, and as an early regulator of adipocyte differentiation. AhR interference with cell-cycle arrest in differentiation may be linked to the increased rate of senescence.


Assuntos
Tecido Adiposo/química , Tecido Adiposo/metabolismo , Hidrocarboneto de Aril Hidroxilases , Receptores de Hidrocarboneto Arílico/genética , Receptores de Hidrocarboneto Arílico/metabolismo , Triglicerídeos/biossíntese , Células 3T3/química , Células 3T3/citologia , Animais , Fatores de Transcrição Hélice-Alça-Hélice Básicos , Diferenciação Celular/fisiologia , Divisão Celular/fisiologia , Linhagem Celular Transformada/química , Linhagem Celular Transformada/citologia , Senescência Celular/fisiologia , Citocromo P-450 CYP1B1 , Sistema Enzimático do Citocromo P-450/genética , Sistema Enzimático do Citocromo P-450/metabolismo , Expressão Gênica/fisiologia , Camundongos , Receptores Citoplasmáticos e Nucleares/genética , Receptores Citoplasmáticos e Nucleares/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Transfecção
13.
J Biol Chem ; 273(9): 5174-83, 1998 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-9478971

RESUMO

Transcriptional activation of the Cyp1B1 gene in rodents is stimulated by both polycyclic hydrocarbons and cAMP. The mouse Cyp1B1 gene structure contains three exons, of which the second nucleotide of exon 2 is the translation start site. Primer extension analysis identified a transcription start domain defining an exon 1 of 371 base pairs. The sequence 1.075 kilobases upstream of the transcription start site showed 11 xenobiotic-responsive elements (XRE) (TnGCGTG or GCGTG) that are putative aryl hydrocarbon receptor (AhR)-binding sites and three steroidogenic factor-1 motifs that are associated with cAMP-mediated transcriptional activation of genes. A transiently transfected Cyp1B1-luciferase construct, composed of exon 1 and 1.075 kilobases of 5'-flanking region, was induced by 2,3, 7,8-tetrachlorodibenzo-p-dioxin (TCDD; 10.0 +/- 3.0-fold, n = 6) in C3H10T1/2 cells, which exclusively express Cyp1B1. The 90-base pair basal promoter contains two SP-1 sites, one SF-1 site, and a TATA-like box. TCDD induction and basal expression were dependent on positive regulatory elements present between -1075 and -810. Five XRE motifs localized in the enhancer region were completely conserved between mouse and human CYP1B1 sequences. Similar inductions were seen in Hepa-1 cells, which express Cyp1A1 but not Cyp1B1. However, basal Cyp1B1 promoter activities were 4-10-fold higher in C3H10T1/2 cells providing the enhancer region was present, partially reproducing the in vivo cell-specific expression of Cyp1B1. Gel shift experiments established that TCDD stimulates AhR binding to the downstream XRE in the enhancer region. However, oligonucleotides that encompass two other XREs show a high affinity complex of similar size that is evident even without TCDD treatment and that does not contain either the AhR or AhR nuclear translocator. The fourth XRE is immediately adjacent to an E-box, and this oligonucleotide formed a smaller complex that was dependent on this E-box sequence. Negative regulatory sequences have been located between the promoter and TCDD-responsive enhancer regions. Constitutive expression of the Cyp1B1 gene was lost in AhR-deficient cells and was restored by transfected AhR cDNA. Reporter constructs function in a parallel manner, demonstrating the key role of the AhR in constitutive as well as TCDD-induced expression of Cyp1B1 in mouse embryo fibroblasts.


Assuntos
Hidrocarboneto de Aril Hidroxilases , Sistema Enzimático do Citocromo P-450/genética , Elementos Facilitadores Genéticos , Regulação Enzimológica da Expressão Gênica , Receptores de Hidrocarboneto Arílico/metabolismo , Animais , Sequência de Bases , Sítios de Ligação , Sequência Conservada , Citocromo P-450 CYP1B1 , Embrião de Mamíferos/citologia , Indução Enzimática , Fibroblastos/citologia , Genes Reporter , Biblioteca Genômica , Humanos , Camundongos , Dados de Sequência Molecular , Proteínas Nucleares/metabolismo , Dibenzodioxinas Policloradas/farmacologia , Regiões Promotoras Genéticas , Ligação Proteica , RNA Mensageiro/biossíntese , Análise de Sequência de DNA , Homologia de Sequência do Ácido Nucleico , Especificidade da Espécie , Fator Esteroidogênico 1 , Transcrição Gênica
14.
Cancer Res ; 57(20): 4498-506, 1997 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-9377560

RESUMO

Cytochrome P4501B1 is highly active in the bioactivation of polycyclic aromatic hydrocarbons (PAHs) to mutagenic metabolites. The C3H mouse embryo fibroblast cell line, C3H10T1/2, and primary mouse embryo fibroblasts (MEFs) express CYP1B1 as the predominant cytochrome P-450 form. This is constitutively expressed and induced by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) but also, to a greater extent, by PAH. To establish the role of the aryl hydrocarbon receptor (AhR) in the induction responses to PAH and TCDD in MEFs, we measured CYP1B1 expression in primary MEFs generated from congenic C57b/6 mice that differ only at the AhR locus. These MEF cells express either b-1 or d-type Ah receptors, with high and low affinities for AhR agonists, respectively. Both types of MEFs express constitutive CYP1B1 to a similar extent, as measured by expression of mRNA, protein, and activity (PAH metabolism). Induction of CYP1B1 in responsive b-1 MEFs exhibited a 5-fold lower EC50 for TCDD, as compared with MEFs expressing d-type AhR. This is fully consistent with AhR mediation of the induction. Maximal induction of CYP1B1 by 10(-8) M TCDD was comparable in each MEF type. Very low levels of CYP1A1 mRNA, detected by reverse transcriptase-PCR, show a similar dependence on AhR phenotype in these MEFs. The expression of CYP1B1 was highly dependent upon the passage number of the primary MEF cultures. Paralleling decreased proliferation of these cells after passage 7 are changes in cell morphology, the appearance of increasing numbers of differentiated cell types, and the complete loss of CYP1B1 expression. Colonies of these MEFs, which have escaped senescence, proliferate at much later passages, regain CYP1B1 expression, and exhibit the same AhR-dependent CYP1B1 induction responses, as observed in early-passage MEFs and the C3H10T1/2 cell line. We conclude that CYP1B1 expression, including induction via the AhR, parallels a proliferative state for MEF cells.


Assuntos
Hidrocarboneto de Aril Hidroxilases , Sistema Enzimático do Citocromo P-450/biossíntese , Microssomos/enzimologia , Dibenzodioxinas Policloradas/farmacologia , Receptores de Hidrocarboneto Arílico/fisiologia , 9,10-Dimetil-1,2-benzantraceno/metabolismo , Animais , Benzo(a)Antracenos/farmacologia , Células Cultivadas , Citocromo P-450 CYP1B1 , Embrião de Mamíferos , Indução Enzimática/efeitos dos fármacos , Fibroblastos/enzimologia , Camundongos , Camundongos Endogâmicos C3H , Camundongos Endogâmicos C57BL , Reação em Cadeia da Polimerase , RNA Mensageiro/biossíntese , Receptores de Hidrocarboneto Arílico/biossíntese , Receptores de Hidrocarboneto Arílico/genética , Transcrição Gênica
16.
Steroids ; 60(3): 290-4, 1995 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-7792834

RESUMO

The initial biosynthetic conversions of cholesterol to the bile acids involve sequential 7 alpha-hydroxylation (catalyzed by cholesterol 7 alpha-hydroxylase) followed by C-3 oxidation and concomitant double bond migration (to a delta 4-configuration, catalyzed by 3 beta-delta 5-C27-steroid oxidoreductase) to provide 7 alpha-hydroxycholest-4-en-3-one. A straightforward, and economical, preparation (on a 0.1 g scale) of this pivotal biosynthetic intermediate has been devised. Reduction of 3 beta-(benzoyloxy)-cholest-5-en-7-one with LiB(sec-butyl)3H provided a 4:1 mixture, respectively, of the 7 alpha- and 7 beta-hydroxy diastereomers, which were separated chromatographically. Solvolytic removal of the C-3 benzoyl group gave 3 beta,7 alpha-cholest-5-ene-3,7-diol. A suspension of the 1:1 (v/v) complex (formed by mutual dissolution in MeOH, followed by evaporation of the solvent) of this diol with hydroxypropyl-beta-cyclodextrin, at a concentration of 1 mg mL-1 (in neutral phosphate buffer), was converted by Brevibacterium sp cholesterol oxidase (0.25 U mg-1 of substrate) and catalase (70 U mg-1 of substrate, to recover O2 from the H2O2 produced by the enzymatic oxidation) to a suspension of 7 alpha-hydroxycholest-4-en-3-one and the hydroxypropyl-beta-cyclodextrin. The yield for the enzymatic conversion was in excess of 90%. A much poorer and less reproducible yield (< 20%) was seen in the absence of the hydroxypropyl-beta-cyclodextrin. Routine extraction of this aqueous suspension, and chromatographic purification (85:15 CHCl3/acetone v/v on silica) of the residue, gave pure 7 alpha-hydroxycholest-4-en-3-one in 68% isolated yield. This route is a significant improvement, in terms of reaction scale and convenience, over the previous procedures for the preparation of this steroid.


Assuntos
Colestenonas/metabolismo , Colesterol Oxidase/metabolismo , Ciclodextrinas/farmacologia , Hidroxicolesteróis/metabolismo , alfa-Ciclodextrinas , beta-Ciclodextrinas , 2-Hidroxipropil-beta-Ciclodextrina , Colestenonas/química , Oxirredução , Estereoisomerismo
17.
J Biol Chem ; 269(21): 14905-11, 1994 May 27.
Artigo em Inglês | MEDLINE | ID: mdl-8195121

RESUMO

A novel benz[a]anthracene and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-inducible cytochrome P-450 (P450EF), which is very active in polycyclic aromatic hydrocarbon metabolism, has been purified from C3H10T1/2 mouse embryo fibroblasts (Pottenger, L. H., Christou, M., and Jefcoate, C. R. (1991) Arch. Biochem. Biophys. 286, 488-497). P450EF was shown to be immunologically unrelated to the major known P-450 families. A 4.9-kilobase (kb) cDNA encoding P450EF has been isolated from a lambda ZAP cDNA expression library generated from mRNA of TCDD-induced C3H10T1/2 cells. This cDNA comprises 175-base pair (bp) 5'-noncoding, 1629-bp open reading, and about 3100-bp 3'-noncoding sequence. A SmaI fragment of the 4.9-kb cDNA hybridized to a 5.2-kb mRNA species equally induced by benz[a]anthracene (10 microM) and TCDD (10 nM) in C3H10T1/2 cells, consistent with the involvement of the Ah receptor in this induction process. The deduced amino acid sequence (543 amino acids), the longest of any known cytochrome P-450, exhibits 41 and 38% identity to mouse CYP1A1 and CYP1A2, respectively, and less but substantial similarity (30-33% identity) to many members of the CYP2 family. There are five extended regions of > or = 50% identity to CYP1A1 as follows: (a) 51-118; (b) 199-222; (c) 326-343 (I-helix, O2-binding threonine); (d) 357-430; and (e) 460-487 (heme-binding cysteine). These sequence relationships suggest that P450EF is a member of a new CYP1B subfamily (mouse CYP1B1). Hybridization of mRNA and immunoblot analyses of microsomes both demonstrated beta-naphthoflavone (beta-NF) inducibility of Cyp1b-1 expression in C3H mouse lung, liver, and uterus although at lower levels relative to Cyp1a-1. The mobility of the beta-NF-inducible immunoreactive liver protein was significantly higher than that of the CYP1B1 protein detected in mouse lung, uterus, and C3H10T1/2 cells. Compared with the beta-NF-induced uterus, polycyclic aromatic hydrocarbon-induced uterine fibroblasts exhibited 10-20-fold higher levels of CYP1B1, suggesting that stromal fibroblasts are a major source of the protein.


Assuntos
Hidrocarboneto de Aril Hidroxilases , Sistema Enzimático do Citocromo P-450/genética , Sequência de Aminoácidos , Animais , Sequência de Bases , Células Cultivadas , Clonagem Molecular , Citocromo P-450 CYP1B1 , DNA Complementar , Feminino , Rim/metabolismo , Fígado/metabolismo , Pulmão/metabolismo , Camundongos , Camundongos Endogâmicos C3H , Dados de Sequência Molecular , Família Multigênica , RNA Mensageiro/metabolismo , Homologia de Sequência de Aminoácidos , Útero/metabolismo
18.
AAOHN J ; 37(3): 101-4, 1989 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-2923627

RESUMO

1. The Labor Occupational Health Program's (LOHP) experience with occupational health problems in minority communities demonstrates that information on a client's past work history and occupational exposures is essential in providing comprehensive health care. Occupational health histories are an excellent tool to utilize in community health. 2. Community clinics and primary health care professionals are integral components in health care delivery services. 3. The occupational health professional has a unique opportunity to provide leadership in educating community health providers about the basics of occupational health.


Assuntos
Agricultura , Grupos Minoritários , Serviços de Saúde do Trabalhador/organização & administração , Atenção Primária à Saúde , California , Humanos
19.
AAOHN J ; 37(3): 105-8, 1989 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-2923628

RESUMO

1. Despite regulatory and case identification efforts, lead exposure continues to pose a major health problem for minority workers. 2. Minority workers are overrepresented in lead industries such as lead smelting, lead storage batteries, lead pigment production and pottery. 3. Preliminary data from recently instituted lead registries in California and Texas suggest that minority workers continue to be overexposed to lead. 4. A federal policy that strengthens enforcement of the OSHA lead standard is needed to reduce lead exposure among minority workers.


Assuntos
Intoxicação por Chumbo/prevenção & controle , Grupos Minoritários , Doenças Profissionais/prevenção & controle , Exposição Ambiental , Humanos , Chumbo/sangue , National Institute for Occupational Safety and Health, U.S. , Estados Unidos , United States Occupational Safety and Health Administration
20.
AAOHN J ; 37(3): 109-13, 1989 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-2923629

RESUMO

1. Large groups of health care workers, many of whom are among ethnic minorities with potential for occupational exposure to HIV/HBV, are generally underserved in training on prevention of occupational transmission of the viruses. 2. The inadequacy of training for indirect client care personnel appears to be one of the primary reasons for high rates of needlestick injuries and exposure to blood. 3. Training in appropriate infection control techniques can help reduce the uneasiness and fear among health care workers over occupationally-related HIV/HBV transmission.


Assuntos
Síndrome da Imunodeficiência Adquirida/transmissão , Pessoal Técnico de Saúde , Grupos Minoritários , Doenças Profissionais/transmissão , Síndrome da Imunodeficiência Adquirida/prevenção & controle , Currículo , Educação Continuada , Humanos , Doenças Profissionais/prevenção & controle , Estados Unidos
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