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1.
Int J Gynaecol Obstet ; 162(1): 169-175, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-37078486

RESUMO

OBJECTIVE: The authors investigated tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis (Tdap) and influenza vaccination during pregnancy following Advisory Committee on Immunization Practices' (ACIP's) recommendation for antenatal pertussis vaccination. METHODS: A retrospective chart review was performed in 2019 of women receiving prenatal care at our institution between January 1, 2014 and December 31, 2018. Receipt of ACIP-recommended vaccines were examined using Current Procedural Terminology codes to identify initiation of prenatal care, then administration of Tdap and influenza vaccines. Data were examined by individual practice (university faculty, community physicians, obstetrics and gynecology (OBGYN) residents, and family medicine residents, practice staff composition, vaccination protocol use, and insurance status. Statistical analyses were performed using χ2 testing and χ2 testing of linear trend. RESULTS: Within our cohort (n = 17 973), highest vaccination uptake occurred in the university-based OBGYN faculty practice (Tdap = 58.2%, influenza = 56.5%) with lowest uptake in the OBGYN resident practice (Tdap = 28.6%, influenza = 18.5%). Higher uptake occurred in practices with standing orders, more advanced practice providers, lower provider to nursing ratios, and lower rates of Medicaid insurance. CONCLUSION: These data demonstrated higher vaccination uptake with standing orders, more advanced practice providers, and lower provider to nurse ratios. Future work optimizing practice staff composition and vaccination protocols may increase vaccine uptake.


Assuntos
Vacinas contra Difteria, Tétano e Coqueluche Acelular , Vacinas contra Influenza , Influenza Humana , Coqueluche , Estados Unidos , Feminino , Humanos , Gravidez , Coqueluche/prevenção & controle , Influenza Humana/prevenção & controle , Estudos Retrospectivos , Vacinação , Vacina contra Coqueluche
2.
Cancer Causes Control ; 23(9): 1451-61, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22763500

RESUMO

PURPOSE: Non-steroidal anti-inflammatory drugs (NSAIDs) have been associated with lower risk of certain cancers, but data on the effect on skin cancer risk have been limited and contradictory. We prospectively examined whether use of NSAIDS or acetaminophen was associated with a lower risk of skin cancer in women. METHODS: The 92,125 Caucasian women in the Nurses' Health Study provided information on aspirin use in 1980. Other NSAIDs and acetaminophen were added in 1990. Medication use, frequency, and quantity were reassessed on biennial questionnaires. Through 2008, we confirmed 658 melanoma cases, 1,337 squamous cell carcinoma (SCC) cases, and had 15,079 self-reports of basal cell carcinoma (BCC). We used COX proportional hazards models to compute relative risks (RR) adjusted for known skin cancer risk factors. RESULTS: Neither aspirin nor non-aspirin NSAID use was associated with a lower risk of melanoma, SCC, or BCC, even for women with high quantity, frequency, or duration of use. Instead, we observed an increased risk of melanoma among current aspirin users (RR = 1.32, 95 % CI 1.03-1.70), though an increase of similar magnitude among past users and lack of a dose-response effect did not support a pharmacologic mechanism. We observed a mild reduction in SCC risk in current acetaminophen users (RR = 0.88, 95 % CI 0.75-1.02), with a linear decrease in risk with greater frequency of use (p = 0.04). CONCLUSIONS: Aspirin and other NSAIDs were not associated with a lower risk of melanoma, SCC, or BCC in women. Our large, prospective study does not support a chemoprotective effect of NSAIDs against skin cancers.


Assuntos
Acetaminofen/administração & dosagem , Anti-Inflamatórios não Esteroides/administração & dosagem , Neoplasias Cutâneas/epidemiologia , Aspirina/administração & dosagem , Carcinoma Basocelular/epidemiologia , Carcinoma Basocelular/prevenção & controle , Carcinoma de Células Escamosas/epidemiologia , Carcinoma de Células Escamosas/prevenção & controle , Feminino , Seguimentos , Humanos , Melanoma/epidemiologia , Melanoma/prevenção & controle , Pessoa de Meia-Idade , Modelos de Riscos Proporcionais , Estudos Prospectivos , Fatores de Risco , Neoplasias Cutâneas/prevenção & controle , Estados Unidos/epidemiologia
3.
ESMO Open ; 7(4): 100526, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-35780590

RESUMO

BACKGROUND: Tumor genomic profiling (TGP) often incidentally identifies germline pathogenic variants (PVs) associated with cancer predisposition syndromes. Methods used by somatic testing laboratories, including germline analysis, differ from designated germline laboratories that have optimized the identification of germline PVs. This study evaluated discrepancies between somatic and germline testing results, and their impact on patients. PATIENTS AND METHODS: Chart reviews were carried out at a single institution for patients who had both somatic and designated germline genetic testing. Cases with discrepant results in which germline PVs were not detected by the somatic laboratory or in which variant classification differed are summarized. RESULTS: TGP was carried out on 2811 cancer patients, 600 of whom also underwent designated germline genetic testing. Germline PVs were identified for 109 individuals. Discrepancies between germline genetic testing and tumor profiling reports were identified in 20 cases, including 14 PVs identified by designated germline genetic testing laboratories that were not reported by somatic testing laboratories and six variants with discrepant classifications between the designated germline and somatic testing laboratories. Three PVs identified by designated germline laboratories are targets for poly adenosine diphosphate-ribose polymerase (PARP) inhibitors and resulted in different treatment options. Of the PVs identified by designated germline laboratories, 60% (n = 12) were in genes with established associations to the patients' cancer, and 40% of the PVs were incidental. The majority (90%) of all discrepant findings, both contributory and incidental, changed management recommendations for these patients, highlighting the importance of comprehensive germline assessment. CONCLUSIONS: Methods used by somatic laboratories, regardless of the inclusion of germline analysis, differ from those of designated germline laboratories for identifying germline PVs. Unrecognized germline PVs may harm patients by missing hereditary syndromes and targeted therapy opportunities (e.g. anti-programmed cell death protein 1 immunotherapy, PARP inhibitors). Clinicians should refer patients who meet the criteria for genetic evaluation regardless of somatic testing outcomes.


Assuntos
Mutação em Linhagem Germinativa , Neoplasias , Predisposição Genética para Doença , Testes Genéticos , Genômica , Células Germinativas , Humanos
4.
Cell Prolif ; 28(3): 145-55, 1995 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-7734624

RESUMO

Protein kinase C (PKC) has been implicated in the signal transduction pathways for the biological effect of both interleukin-3 (IL-3) and erythropoietin (EPO) in hematopoietic target cells. The goal of this study was to identify specific classical isoforms of PKC and their localization in hematopoietic cells in response to the growth factors, IL-3 or EPO. In addition to murine fetal liver cells as a source of normal erythroid progenitor cells, we have utilized the B6SUt.EP cell line, a non-transformed hematopoietic cell line that requires IL-3 for proliferation, but for which EPO can substitute as a growth factor. With polyclonal antibodies prepared against peptide sequences specific for the alpha, beta I, beta II and gamma isoforms of PKC, we have identified beta I and beta II as the predominant nuclear isoforms in target cells that proliferate in response to IL-3 or EPO.


Assuntos
Núcleo Celular/enzimologia , Eritropoetina/farmacologia , Células-Tronco Hematopoéticas/efeitos dos fármacos , Interleucina-3/farmacologia , Proteína Quinase C/metabolismo , Animais , Compartimento Celular , Fracionamento Celular , Células Cultivadas , Células-Tronco Hematopoéticas/enzimologia , Processamento de Imagem Assistida por Computador , Immunoblotting , Imuno-Histoquímica , Isoenzimas/isolamento & purificação , Isoenzimas/metabolismo , Fígado/citologia , Camundongos , Proteína Quinase C/agonistas , Proteína Quinase C/isolamento & purificação , Proteína Quinase C beta
5.
J Endocrinol ; 84(1): 49-63, 1980 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-6244356

RESUMO

The present experiments were designed to study whether exogenous LH could elicit acute cyclic AMP-mediated activation of cyclic AMP-dependent protein kinase and phosphorylation of cellular protein in intact porcine granulosa cells. Incubation of porcine granulosa cells (from 3 to 5 mm diameter follicles) with 2 microgram luteinizing hormone/ml (LH) caused a significant rise of cellular cyclic AMP content within 2 min of the addition of LH. The increase was dose-dependent and occurred between doses of 0.2 and 2.0 microgram LH/ml. Luteinizing hormone also caused a time- and dose-dependent dissociation of the type II cyclic AMP-dependent protein kinase isozyme in porcine granulosa cells. Luteinizing hormone (0.05--2 microgram/ml) significantly dissociated the cyclic AMP-dependent protein kinase between 2 and 30 min after stimulation. The protein kinase dissociation was a specific effect of LH and was not elicited by either adrenocorticotrophic hormone or prolactin. During the period of LH-induced protein kinase activation, several soluble granulosa cell proteins, ranging in molecular weights from about 43 000 to 99 000, became phosphorylated in a time-dpeendent and hormone-specific manner. The results suggest that cyclic AMP-mediated activation of granulosa cell type II cyclic AMP-dependent protein kinase may be a prerequisite in the short-term molecular action of LH leading to LH-specific phosphorylation of several soluble granulosa cell proteins of an as yet unidentified function.


Assuntos
Células da Granulosa/metabolismo , Hormônio Luteinizante/farmacologia , Proteínas Quinases/metabolismo , Animais , Células Cultivadas , AMP Cíclico/metabolismo , Eletroforese em Gel de Poliacrilamida , Ativação Enzimática/efeitos dos fármacos , Feminino , Células da Granulosa/efeitos dos fármacos , Células da Granulosa/enzimologia , Fosforilação , Progesterona/metabolismo , Proteínas/metabolismo , Estimulação Química , Frações Subcelulares/metabolismo , Suínos
6.
Chest ; 83(6): 925-6, 1983 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-6851698

RESUMO

Necrotizing fasciitis is a serious, rapidly progressive infection of subcutaneous tissue and fascia, most often related to trauma or surgery. We report a case of necrotizing fasciitis which occurred as a complication of tube thoracostomy. Physicians performing tube thoracostomy should be aware of this potential complication, since definitive treatment requires not only antibiotic therapy, but also surgical debridement.


Assuntos
Drenagem/instrumentação , Fasciite/etiologia , Cirurgia Torácica , Adulto , Empiema/diagnóstico , Empiema/cirurgia , Fasciite/diagnóstico , Fasciite/patologia , Feminino , Humanos , Necrose , Derrame Pleural/diagnóstico por imagem , Derrame Pleural/etiologia , Punções/efeitos adversos , Radiografia
7.
J Cancer Res Clin Oncol ; 122(8): 465-75, 1996.
Artigo em Inglês | MEDLINE | ID: mdl-8698746

RESUMO

Dexniguldipine hydrochloride (DNIG) is a potent antineoplastic agent with well-documented anti-(protein kinase C) activity and an ability to reverse multidrug resistance. Given the importance of protein kinase C (PKC) activity in proliferation and differentiation, we examined the effect of DNIG on several parameters of Friend erythroleukemia cell (FELC) activity. Particular attention was paid to proliferation, hexamethylene-bisacetamide-(HMBA)-induced differentiation, nuclear localization of protein kinase C, and nuclear protein phosphorylation. P-glycoprotein expression was also followed as an indicator of changes in multidrug resistance. At 2.5 microM, DNIG caused a significant decrease in the rate of FELC proliferation, while maintaining a cellular viability of greater than 80%, whether exposure to the drug was continuous over 96 h or took the form of a 6-h pulse/chase. DNA synthesis was decreased in cells exposed to DNIG for 20 h. Flow cytometry showed a marked increase in the percentage of cells in S phase of the cell cycle. Phosphorylation studies revealed decreased phosphorylation of two nuclear proteins (80 kDa and 47 kDa) following a 4-h exposure to the drug. HMBA-induced differentiation was significantly inhibited with continuous exposure to DNIG, and this effect appears to be a pre-commitment one, as 6-h pulse/chase exposures also resulted in inhibition of differentiation. Cells induced to differentiate with HMBA also demonstrated a decrease in the quantity of the 80-kDa phosphoprotein. Western blotting revealed that, even in the face of decreased phosphorylation, exposure to this PKC inhibitor resulted in an increase in the amount of nuclear PKC alpha. Finally, levels of P-glycoprotein were decreased in the presence of this drug. Our work identifies several effects of the PKC inhibitor DNIG on FELC and suggests several roles for PKC in regulating FELC proliferation and differentiation. Additionally, these results suggest that this PKC inhibitor may increase the effect of other chemotherapeutic drugs, particularly S-phase-specific ones, by increasing the length of S phase and decreasing multidrug resistance. The possibility of combination therapy with DNIG and other antineoplastic agents should be investigated further in light of these findings.


Assuntos
Membro 1 da Subfamília B de Cassetes de Ligação de ATP/análise , Antineoplásicos/farmacologia , Di-Hidropiridinas/farmacologia , Proteínas Nucleares/metabolismo , Proteína Quinase C/antagonistas & inibidores , Acetamidas/farmacologia , Animais , Ciclo Celular/efeitos dos fármacos , Diferenciação Celular/efeitos dos fármacos , Vírus da Leucemia Murina de Friend , Leucemia Eritroblástica Aguda/metabolismo , Leucemia Eritroblástica Aguda/patologia , Camundongos , Camundongos Endogâmicos DBA , Fosforilação , Células Tumorais Cultivadas
8.
Arch Pediatr Adolesc Med ; 154(7): 673-8, 2000 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-10891018

RESUMO

OBJECTIVE: To determine the response, in terms of fecal hemoglobin excretion and clinical symptoms, of normal 9 1/2-month-old infants to being fed cow milk. DESIGN: Longitudinal (before-after) trial in which each infant was fed formula for 1 month (baseline) followed by 3 months during which cow milk was fed. SETTING: Healthy infants living in Iowa City, Iowa, a town with a population of about 60,000. MAIN OUTCOME MEASURES: Hemoglobin concentration in spot stools, 96-hour quantitative fecal hemoglobin excretion, stool characteristics, feeding-related behaviors, and iron nutritional status. RESULTS: Fecal hemoglobin concentration during formula feeding (baseline) was higher than previously observed in younger infants. Nine of 31 infants responded to cow milk feeding with increased fecal hemoglobin concentration. Fecal hemoglobin concentration (mean +/- SD) of the 9 responders rose from 1,395 +/- 856 microg/g of dry stool (baseline) to 2,711 +/- 1,732 microg/g of dry stool (P=.01). The response rate (29%) was similar to that in younger infants, but the intensity of the response was much less. Quantitative hemoglobin excretion was in general agreement with estimates based on spot stool hemoglobin concentrations. Cow milk feeding was not associated with recognizable changes in stool characteristics, nor were there clinical signs related to fecal blood loss. Iron status was similar, except that after 3 months of cow milk feeding responders showed lower (P= .047) ferritin concentrations than nonresponders. CONCLUSIONS: Cow milk-induced blood loss is present in 9 1/2-month-old infants but is of such low intensity that its clinical significance seems questionable. Nevertheless, infants without cow milk-induced blood loss were in better iron nutritional status than infants who showed blood loss.


Assuntos
Anemia Ferropriva/etiologia , Alimentação com Mamadeira , Leite/efeitos adversos , Sangue Oculto , Anemia Ferropriva/diagnóstico , Animais , Feminino , Ferritinas/sangue , Humanos , Lactente , Estudos Longitudinais , Masculino
9.
Ann Thorac Surg ; 55(5): 1192-6, 1993 May.
Artigo em Inglês | MEDLINE | ID: mdl-7684218

RESUMO

Chronic lymphocytic leukemia is a disease of the elderly. It tends to have a variable clinical course. Because of the patients' immunologically dysfunctional state, there has been reluctance to perform open cardiac procedures because of concern about early postoperative sepsis leading to death. To assess the risk of coronary artery bypass grafting in elderly patients, the records of 26 patients (mean age, 69.6 +/- 4.9 years) with chronic lymphocytic leukemia who underwent coronary artery bypass grafting between January 1975 and July 1990 were retrospectively reviewed. Nineteen underwent isolated coronary artery bypass grafting, and 7 had combined procedures. The operative mortality rate was 7.7%. Postoperative infections developed in 6 patients (23.1%): pneumonia in 3 and sternal osteomyelitis, acute parotiditis, and bacteremia in 1 each. One of these 6 patients died of acute Serratia pneumonitis. Twenty-four patients (92.3%) were discharged from the hospital an average of 10.6 +/- 7.7 days postoperatively. Patients with chronic lymphocytic leukemia can undergo coronary artery bypass grafting with acceptable mortality but with increased risk of postoperative infection.


Assuntos
Ponte de Artéria Coronária , Leucemia Linfocítica Crônica de Células B , Idoso , Infecções Bacterianas/etiologia , Feminino , Seguimentos , Hemoglobinas/análise , Humanos , Tempo de Internação , Leucemia Linfocítica Crônica de Células B/sangue , Leucemia Linfocítica Crônica de Células B/patologia , Contagem de Leucócitos , Linfócitos/patologia , Masculino , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Neutrófilos/patologia , Contagem de Plaquetas , Estudos Retrospectivos , Fatores de Risco , Fatores de Tempo , gama-Globulinas/análise
10.
Life Sci ; 67(4): 471-6, 2000 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-11003057

RESUMO

The endogenous peptides endomorphins 1 and 2 are newly discovered, potent, selective mu-opioid receptor agonists. In the present study, the effects of endomorphins 1 and 2 on vascular smooth muscle tone were investigated on isolated rings from rat aorta with and without endothelium. In rings precontracted with phenylephrine, endomorphins 1 and 2 at concentrations of 0.1 and 1.0 microM, nociceptin at concentrations of 1-100 microM, and adrenomedullin at concentrations of 0.01-1.0 microM induced concentration dependent relaxant responses. The endomorphins and nociceptin were less potent than adrenomedullin. No relaxation was induced by endomorphins 1 and 2 in aortic rings denuded of endothelium and precontracted with phenylephrine. The results of the present studies demonstrate that the endomorphins relax aortic vascular smooth muscle from the rat aorta by an endothelium-dependant mechanism.


Assuntos
Analgésicos Opioides/farmacologia , Contração Muscular/fisiologia , Músculo Liso Vascular/fisiologia , Oligopeptídeos/farmacologia , Vasodilatadores/farmacologia , Adrenomedulina , Albuterol/farmacologia , Animais , Aorta Abdominal/efeitos dos fármacos , Aorta Torácica/efeitos dos fármacos , Relação Dose-Resposta a Droga , Endotélio Vascular/fisiologia , Técnicas In Vitro , Masculino , Contração Muscular/efeitos dos fármacos , Músculo Liso Vascular/efeitos dos fármacos , Peptídeos Opioides/farmacologia , Peptídeos/farmacologia , Ratos , Ratos Sprague-Dawley , Receptores Opioides mu/agonistas , Nociceptina
11.
J AOAC Int ; 79(4): 953-61, 1996.
Artigo em Inglês | MEDLINE | ID: mdl-8757454

RESUMO

A comprehensive screening and confirmatory method was developed for monitoring polychlorinated biphenyls (PCBs), both as Aroclors and as individual congeners. This approach incorporates extraction, extract cleanup, and analysis modules designed to match cost, time, and data quality requirements. Soxhlet, sonication, supercritical fluid, and accelerated solvent extractions were evaluated. Carbon chromatographic cleanup procedures were used for separation of congeners on the basis of ortho substitutions, which permitted calculation of toxicity equivalents. Individual congener determinations, congener total histograms, and peak comparison techniques for Aroclor identification were elaborated by using high and low resolution mass spectrometric data. A screening procedure based on immunoassay using the Ohmicron PCB RaPID Assay kit gave results comparable to those obtained by gas chromatography with electron capture detection in the range 0.40-230 ppm, when the appropriate Aroclor calibrator was used.


Assuntos
Arocloros/análise , Bifenilos Policlorados/análise , Poluentes do Solo/análise , Arocloros/metabolismo , Calibragem , Ensaio de Imunoadsorção Enzimática , Cromatografia Gasosa-Espectrometria de Massas , Hexanos/química , Cloreto de Metileno/química , Padrões de Referência , Solventes/química
12.
Int J Health Serv ; 31(2): 441-4, 2001.
Artigo em Inglês | MEDLINE | ID: mdl-11407177

RESUMO

World Bank loan policies in Mozambique have almost killed off the country's cashew-processing industry by requiring the removal of the export tariff on raw cashews, a tax that Mozambique had instituted to ensure the cashew supply for local factories.


Assuntos
Comércio/economia , Países em Desenvolvimento/economia , Organização do Financiamento , Indústria Alimentícia/economia , Agências Internacionais/organização & administração , Política Organizacional , Coerção , Competição Econômica , Estudos de Avaliação como Assunto , Humanos , Moçambique , Objetivos Organizacionais , Pobreza/tendências , Impostos , Desemprego/tendências
15.
Am J Physiol Lung Cell Mol Physiol ; 288(1): L202-11, 2005 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-15257984

RESUMO

Pulmonary hypertension is characterized by vascular remodeling involving smooth muscle cell proliferation and migration. Calcitonin gene-related peptide (CGRP) and nitric oxide (NO) are potent vasodilators, and the inhibition of aortic smooth muscle cell (ASMC) proliferation by NO has been documented, but less is known about the effects of CGRP. The mechanism by which overexpression of CGRP inhibits proliferation in pulmonary artery smooth muscle cells (PASMC) and ASMC following in vitro transfection by the gene coding for prepro-CGRP was investigated. Increased expression of p53 is known to stimulate p21, which inhibits G(1) cyclin/cdk complexes, thereby inhibiting cell proliferation. We hypothesize that p53 and p21 are involved in the growth inhibitory effect of CGRP. In this study, CGRP was shown to inhibit ASMC and PASMC proliferation. In PASMC transfected with CGRP and exposed to a PKA inhibitor (PKAi), cell proliferation was restored. p53 and p21 expression increased in CGRP-treated cells but decreased in cells treated with CGRP and PKAi. PASMC treated with CGRP and a PKG inhibitor (PKGi) recovered from inhibition of proliferation induced by CGRP. ASMC treated with CGRP and then PKAi or PKGi recovered only when exposed to the PKAi and not PKGi. Although CGRP is thought to act through a cAMP-dependent pathway, cGMP involvement in the response to CGRP has been reported. It is concluded that p53 plays a role in CGRP-induced inhibition of cell proliferation and cAMP/PKA appears to mediate this effect in ASMC and PASMC, whereas cGMP appears to be involved in PASMC proliferation.


Assuntos
8-Bromo Monofosfato de Adenosina Cíclica/análogos & derivados , Aorta/citologia , Peptídeo Relacionado com Gene de Calcitonina/farmacologia , GMP Cíclico/análogos & derivados , Miócitos de Músculo Liso/citologia , Artéria Pulmonar/citologia , 8-Bromo Monofosfato de Adenosina Cíclica/farmacologia , Animais , Peptídeo Relacionado com Gene de Calcitonina/genética , Peptídeo Relacionado com Gene de Calcitonina/metabolismo , Divisão Celular/efeitos dos fármacos , Células Cultivadas , AMP Cíclico/metabolismo , Proteínas Quinases Dependentes de AMP Cíclico/antagonistas & inibidores , GMP Cíclico/metabolismo , GMP Cíclico/farmacologia , Proteínas Quinases Dependentes de GMP Cíclico/antagonistas & inibidores , Inibidores Enzimáticos/farmacologia , Masculino , Ratos , Ratos Sprague-Dawley , Tionucleotídeos/farmacologia , Transfecção
16.
Cell Tissue Kinet ; 18(2): 159-68, 1985 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-2982493

RESUMO

The cell-cycle-related activities of the cAMP- and cGMP-dependent phosphodiesterases of Physarum polycephalum were assayed. The activities of plasmodial homogenate and of selected subcellular fractions were measured. The results suggested the presence of both cAMP- and cGMP-dependent phosphodiesterase in the isolated nuclei of P. polycephalum. In addition, they reveal that the cAMP- and cGMP-dependent phosphodiesterase activities of the subcellular fractions fluctuate throughout the cell cycle. The whole-cell homogenates exhibit no cell-cycle-related changes in the presence of 5 X 10(-4) M cGMP. Kinetic data suggest the presence of multiple phosphodiesterase activities in the homogenate and its particulate fractions for the cGMP-dependent enzyme. Multiple cAMP activities are also suggested for the particulate fractions. The Km values indicate that the substrate affinities of the phosphodiesterases from P. polycephalum are similar to those found previously in mammalian systems.


Assuntos
3',5'-AMP Cíclico Fosfodiesterases/metabolismo , 3',5'-GMP Cíclico Fosfodiesterases/metabolismo , Ciclo Celular , Physarum/enzimologia , Cinética , Physarum/citologia , Frações Subcelulares/metabolismo
17.
Biochem Cell Biol ; 68(7-8): 1052-6, 1990.
Artigo em Inglês | MEDLINE | ID: mdl-2223013

RESUMO

Endogenous arachidonic acid metabolism and protein phosphorylation have been examined in Friend erythroleukemia cells in response to the induction of differentiation by dimethyl sulfoxide and hexamethylene bisacetamide. 15-Hydroxyeicosatetraenoic acid levels were elevated in cells differentiated with hexamethylene bisacetamide or dimethyl sulfoxide compared with undifferentiated cells. Protein phosphorylation decreased markedly in differentiated cells compared with undifferentiated cells and the addition of 15-hydroperoxyeicosatetraenoic acid specifically decreased the phosphorylation of a 28-kilodalton protein. These findings indicate that products of 15-lipoxygenase may act as intracellular messengers in Friend erythroleukemia cells by affecting protein phosphorylation.


Assuntos
Araquidonato 15-Lipoxigenase/metabolismo , Vírus da Leucemia Murina de Friend , Leucemia Eritroblástica Aguda/metabolismo , Leucotrienos/farmacologia , Peróxidos Lipídicos/farmacologia , Proteínas de Neoplasias/metabolismo , Animais , Linhagem Celular , Camundongos , Proteínas de Neoplasias/efeitos dos fármacos , Fosforilação/efeitos dos fármacos
18.
Biochem Cell Biol ; 70(7): 555-64, 1992 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-1449723

RESUMO

The relationship between cell proliferation and differentiation has long been a source of controversy. Stimulation of normal erythroid maturation results in a finite number of cell divisions accompanied by a concomitant accumulation of hemoglobin. Friend erythroleukemia cells treated with hexamethylene bisacetamide differentiate in a similar manner, while agents such as hemin apparently induce differentiation without limiting cell proliferation. Aphidicolin, an inhibitor of DNA synthesis, has been reported to induce differentiation in the absence of cell proliferation. Using these three chemicals we have investigated the relationship between cell proliferation and erythrocytic maturation by exposing Friend erythroleukemia cells to either hexamethylene bisacetamide (5 mM), hemin (100 microM), or aphidicolin 1.2 microM) and examining the effects on cell growth, morphology, and hemoglobin production. Proliferation in the presence of hexamethylene bisacetamide is limited to four to five rounds of cell division, while hemin has no inhibitory effect. Hexamethylene bisacetamide initiates the complete erythrocytic maturation program, including cellular structural changes and hemoglobin synthesis. Hemin stimulates only globin gene transcription, not differentiation. Aphidicolin inhibits cell growth within 24 h, but does not induce differentiation. Furthermore, inhibition of proliferation by aphidicolin prevents subsequent hexamethylene bisacetamide induced differentiation. These results indicate that at least one round of cell division is required for initiation of erythrocytic differentiation.


Assuntos
Vírus da Leucemia Murina de Friend , Leucemia Eritroblástica Aguda/patologia , Acetamidas/farmacologia , Animais , Afidicolina/farmacologia , Diferenciação Celular/efeitos dos fármacos , Divisão Celular/efeitos dos fármacos , Replicação do DNA/efeitos dos fármacos , Regulação Leucêmica da Expressão Gênica/efeitos dos fármacos , Hemina/farmacologia , Hemoglobinas/biossíntese , Leucemia Eritroblástica Aguda/metabolismo , Camundongos , Proteínas de Neoplasias/biossíntese , Células Tumorais Cultivadas
19.
Anat Rec ; 194(4): 547-62, 1979 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-475016

RESUMO

Electron microscopic observations and measurements were made on thin-sectioned chromatin fibers and fibrils obtained from nuclei of mature chicken erythrocytes. The nuclei were isolated in low ionic strength gum arabic and octanol then extracted sequentially with (1) 0.14 M NaCl, (2) 0.25 N HCl, (3) buffer saturated phenol, (4) hot 5% SDS and 0.14 M 2-mercaptoethanol and, (5) 0.4 N NaOH. The amount of nuclear protein removed at each of the first four extraction steps was 1, 86, 3 and 11% of the total, respectively. Each extract was characterized by electrophoretic profiles. At each extraction the chromatin was fixed by adding large quantities of a mixture of equal volumes of sodium cacodylate buffered 8% (w/v) glutaraldehyde (pH 6.8) and 2% OsO4 (w/v), directly into (1) an aliquot of the chromatin in extraction fluid, and (2) an aliquot of the chromatin after water washing and swelling. Three size classes of chromatin structure were seen in thin sections prepared for high resolution transmission electron microscopy and stained with uranyl acetate and lead citrate. A thick fiber of about 25 + nm diameter was the predominant large fiber seen in freshly isolated nuclei or in nuclei after salt extraction. This 25 + nm fiber has a substructure consisting of 3.2-5.2 nm diameter fibrils. After water swelling of such freshly isolated or salt extracted nuclei a fiber of about 10 nm diameter was the predominant large fiber instead of the 25 nm diameter fiber. The HCl extraction step which is known to remove histones, caused the disappearance of both the 25 nm and the 10 nm fibers. High magnification (600,000 x) micrographs of the chromatin at all procedural steps, except the last NaOH step, reveal the fibril to be omnipresent. This fibril tends to decrease somewhat in diameter during the protein extraction steps to a 2.5 nm diameter fibril after the hot SDS extraction. A fibril of 2.5 nm diameter is expected of naked double helical DNA stained with a positive stain. The NaOH, which is known to denature DNA, completely destroyed the remaining fibril. We inerpret our results to indicate that the larger chromatin fiber seen in micrographs of thin-sectioned chromatin has a fibrillar substructure which probably represents a double coil of native DNA which may have a thin protein coating of its own. The latter fibril may in turn be wrapped around a hydrophobic histone domain, perhaps reflected in the 10 nm diameter fiber which is seen upon swelling of the chromatin. This 10 nm diameter fiber is thought to be further packaged by folding into the 25 + nm diameter chromatin fiber most frequently reported in thin sections of eukaryotic cell nuclei in situ.


Assuntos
Cromatina/ultraestrutura , Animais , Núcleo Celular/ultraestrutura , Fenômenos Químicos , Química , Galinhas , Cromatina/análise , DNA/análise , Eletroforese em Gel de Poliacrilamida , Eritrócitos/ultraestrutura , Lipídeos/análise , Microscopia Eletrônica , Fosfolipídeos/análise , Conformação Proteica , Proteínas/análise , Água
20.
Biochem Cell Biol ; 71(1-2): 1-6, 1993.
Artigo em Inglês | MEDLINE | ID: mdl-8392352

RESUMO

Induction of maturation in Friend erythroleukemia cells is accompanied by a programmed cessation in cell proliferation and a concomitant increase in hemoglobin production. To investigate the role of protein kinase activity in the initiation of Friend erythroleukemia cell differentiation, autoradiographs of one-dimensional, nondenaturing gels were prepared from Friend erythroleukemia cells either untreated or preincubated with dimethyl sulfoxide (DMSO) or aphidicolin for a 30-min period. Extracts were treated with cAMP or cGMP prior to electrophoresis and assayed for protein kinase activity in the presence of endogenous or exogenously added histone substrates. The data demonstrated differences in protein kinase activity following exposure of Friend erythroleukemia cells to either DMSO or aphidicolin for 30 min. These changes in enzyme activity varied with the treatment of the cells and the substrate used. Two sets of protein kinases, one responsive to cAMP and the other responsive to cGMP, were activated in control cultures. A different cAMP-responsive enzyme was active only in differentiating cells. Another protein kinase, activated by cGMP, was associated with both DMSO and aphidicolin treatment. All of these protein kinases had a histone substrate preference. One noncyclic nucleotide activated protein kinase phosphorylating endogenous substrates was associated only with DMSO-induced cells. These findings suggest a multifaceted role for protein kinases early in the maturation of Friend erythroleukemia cells.


Assuntos
Diferenciação Celular , Vírus da Leucemia Murina de Friend , Leucemia Eritroblástica Aguda/enzimologia , Proteínas Quinases/metabolismo , Afidicolina/farmacologia , Diferenciação Celular/efeitos dos fármacos , AMP Cíclico/metabolismo , GMP Cíclico/metabolismo , Dimetil Sulfóxido/farmacologia , Histonas/metabolismo , Fatores de Tempo , Células Tumorais Cultivadas
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