RESUMO
AIM: Imaging for pelvic floor defaecatory dysfunction includes defaecation proctography. Integrated total pelvic floor ultrasound (transvaginal, transperineal, endoanal) may be an alternative. This study assesses ultrasound accuracy for the detection of rectocele, intussusception, enterocele and dyssynergy compared with defaecation proctography, and determines if ultrasound can predict symptoms and findings on proctography. Treatment is examined. METHOD: Images of 323 women who underwent integrated total pelvic floor ultrasound and defaecation proctography between 2011 and 2014 were blindly reviewed. The size and grade of rectocele, enterocele, intussusception and dyssynergy were noted on both, using proctography as the gold standard. Barium trapping in a rectocele or a functionally significant enterocele was noted on proctography. Demographics and Obstructive Defaecation Symptom scores were collated. RESULTS: The positive predictive value of ultrasound was 73% for rectocele, 79% for intussusception and 91% for enterocele. The negative predictive value for dyssynergy was 99%. Agreement was moderate for rectocele and intussusception, good for enterocele and fair for dyssynergy. The majority of rectoceles that required surgery (59/61) and caused barium trapping (85/89) were detected on ultrasound. A rectocele seen on both transvaginal and transperineal scanning was more likely to require surgery than if seen with only one mode (P = 0.0001). If there was intussusception on ultrasound the patient was more likely to have surgery (P = 0.03). An enterocele visualized on ultrasound was likely to be functionally significant on proctography (P = 0.02). There was, however, no association between findings on imaging and symptoms. CONCLUSION: Integrated total pelvic floor ultrasound provides a useful screening tool for women with defaecatory dysfunction such that defaecatory imaging can avoided in some.
Assuntos
Constipação Intestinal/diagnóstico por imagem , Defecografia/métodos , Endossonografia/métodos , Distúrbios do Assoalho Pélvico/diagnóstico por imagem , Diafragma da Pelve/diagnóstico por imagem , Adulto , Idoso , Idoso de 80 Anos ou mais , Ataxia/complicações , Ataxia/diagnóstico por imagem , Ataxia/fisiopatologia , Bário , Constipação Intestinal/etiologia , Constipação Intestinal/fisiopatologia , Meios de Contraste , Defecação/fisiologia , Feminino , Hérnia/complicações , Hérnia/diagnóstico por imagem , Hérnia/fisiopatologia , Humanos , Intussuscepção/complicações , Intussuscepção/diagnóstico por imagem , Intussuscepção/fisiopatologia , Pessoa de Meia-Idade , Diafragma da Pelve/fisiopatologia , Distúrbios do Assoalho Pélvico/complicações , Distúrbios do Assoalho Pélvico/fisiopatologia , Valor Preditivo dos Testes , Retocele/complicações , Retocele/diagnóstico por imagem , Retocele/fisiopatologia , Índice de Gravidade de Doença , Método Simples-CegoRESUMO
BACKGROUND: The aim of this study was to assess whether a noninvasive imaging technique such as ultrasound could visualize an epidural catheter in the epidural space in children. METHODS: Following local ethics committee approval and informed parental consent a pilot study of 12 cases was performed. Children undergoing major surgery requiring epidural analgesia were recruited. All catheters were introduced via the lumbar region. All children were scanned within 24 h of epidural insertion by consultant paediatric radiologists. If the catheter was identified in the epidural space then an attempt was made to visualize the entire length of the catheter. RESULTS: The epidural catheter was detected in nine of 12 patients. All of these were less than 6 months old. The entire length of the catheter was visualized in five of the nine patients. It was possible to estimate the most cephalad level of the catheter in seven of the nine patients. This was in the thoracic region in all cases and an appropriate level for the intended surgical procedure. It was not possible to precisely identify the tip of the catheter as a distinct entity using ultrasound. CONCLUSION: This study shows that it is possible to visualize an epidural catheter in the epidural space in children under 6 months of age using ultrasound.
Assuntos
Analgesia Epidural/instrumentação , Cateteres de Demora , Fatores Etários , Espaço Epidural/diagnóstico por imagem , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Projetos Piloto , Sensibilidade e Especificidade , UltrassonografiaRESUMO
Previously, we have shown that apoptosis induced by influenza virus was inhibited by an anti-neuraminidase compound [4-guanidino-2, 3-dehydro-N-acetylneuraminic acid (GG167; Relenza; Zanamivir)], which does not enter cells, and acts at the attachment/entry phase of virus replication. Furthermore, a virulent virus, clone 7a, induced greater levels of apoptosis than the attenuated A/Fiji and had greater neuraminidase (NA) activity. To confirm more directly that NA induces apoptosis, the NA of clone 7a and A/Fiji was expressed fused to the Herpes simplex virus tegument coat protein VP22, transfected into HeLa cells and the level of apoptosis determined. VP22 translocates between cells via the medium thus allowing expressed proteins to transfer to a larger number of cells than those originally transfected. Clone 7a NA fused to VP22 induced a significant level of apoptosis whereas A/Fiji NA/VP22 did not, confirming that NA activity is an important determinant of apoptosis acting during fusion protein translocation between cells. Furthermore, the induction of apoptosis was abrogated by antibody to transforming growth factor-beta, which is activated by NA. This approach also showed that VP22/NS1 proteins of both clone 7a and A/Fiji induced apoptosis when expressed alone but inhibited double stranded RNA-induced apoptosis suggesting that this protein may have a dual mode of action. Also, the M1 and M2 proteins of both viruses induced apoptosis but their NP proteins did not.
Assuntos
Apoptose , Neuraminidase/fisiologia , Orthomyxoviridae/enzimologia , Fosfoproteínas/genética , Proteínas Recombinantes de Fusão/fisiologia , Simplexvirus/química , Proteínas não Estruturais Virais/fisiologia , Proteínas Estruturais Virais/genética , Clonagem Molecular , Vetores Genéticos , Células HeLa , Humanos , Vírus da Influenza A/genética , Vírus da Influenza A/fisiologia , Microscopia Confocal , Dados de Sequência Molecular , Neuraminidase/genética , Transfecção , Fator de Crescimento Transformador beta/metabolismo , Proteínas da Matriz Viral/genética , Proteínas da Matriz Viral/fisiologia , Proteínas não Estruturais Virais/genéticaAssuntos
Procedimentos Cirúrgicos Cardíacos , Leucócitos , Depleção Linfocítica , Animais , Perda Sanguínea Cirúrgica , Encéfalo/fisiopatologia , Ponte Cardiopulmonar/instrumentação , Desenho de Equipamento , Filtração , Coração/fisiopatologia , Parada Cardíaca Induzida , Transplante de Coração , Humanos , Embolia Intracraniana/prevenção & controle , Complicações Intraoperatórias/etiologia , Complicações Intraoperatórias/prevenção & controle , Leucócitos/metabolismo , Pulmão/fisiopatologia , Transplante de Pulmão , Ativação Linfocitária , Depleção Linfocítica/instrumentação , Depleção Linfocítica/métodos , Modelos Animais , Miocárdio/patologia , Complicações Pós-Operatórias/etiologia , Complicações Pós-Operatórias/prevenção & controle , Traumatismo por Reperfusão/etiologia , Traumatismo por Reperfusão/prevenção & controle , Sucção , Síndrome de Resposta Inflamatória Sistêmica/etiologia , Síndrome de Resposta Inflamatória Sistêmica/prevenção & controleRESUMO
Primary malignant rhabdoid tumour of the central nervous system is a rare neoplasm affecting children. We present a pathologically proven case, which was initially referred to the paediatric surgeons as a sebaceous cyst, and highlights the importance of imaging prior to surgery of potentially innocuous scalp lesions. Imaging features on CT and MRI are presented, which show bony involvement not previously reported in the literature.
Assuntos
Neoplasias Encefálicas/diagnóstico , Tumor Rabdoide/diagnóstico , Neoplasias Encefálicas/diagnóstico por imagem , Criança , Feminino , Humanos , Imageamento por Ressonância Magnética , Cintilografia , Tumor Rabdoide/diagnóstico por imagem , Tumor Rabdoide/secundário , Neoplasias Cranianas/diagnóstico por imagem , Neoplasias Cranianas/secundário , Tomografia Computadorizada por Raios XRESUMO
The dopamine D2 receptor belongs to the serpentine superfamily of receptors, which have seven transmembrane segments and activate G proteins. D2 receptors are known to be linked, through Galpha(o)- and Galpha(i)-containing G proteins, to several signaling pathways in neuronal and secretory cells, including inhibition of adenylyl cyclase and high voltage-activated Ca2+ channels (HVA-CCs). The dopamine D2 receptor exists in two alternatively spliced isoforms, "long" and "short" (D2L, and D2S, respectively), which have identical ligand binding sites but differ by 29 amino acids in the third intracellular loop, the proposed site for G protein interaction. This has led to the speculation that the two isoforms may interact with different G proteins. We have transfected the AtT20 cell line with either D2L (KCL line) or D2S (KCS line) to facilitate experimentation on the individual isoforms. Both lines show dopamine agonist-dependent inhibition of Q-type HVA-CCs. We combined G protein antisense knock-down studies with multiwavelength fluorescence video microscopy to measure changes in HVA-CC inhibition to investigate the possibility of differential G protein coupling to this inhibition. The initial, rapid, K+ depolarization-induced increase in intracellular Ca2+ concentration is due to influx through HVA-CCs. Our studies reveal that both D2 isoforms couple to Galpha(o) to partially inhibit this influx. However, D2L also couples to Galpha(i)3, whereas D2S couples to Galpha(i)2. These data support the hypothesis of differential coupling of D2 receptor isoforms to G proteins.
Assuntos
Bloqueadores dos Canais de Cálcio , Cálcio/metabolismo , Proteínas de Ligação ao GTP/fisiologia , Isoformas de Proteínas/metabolismo , Receptores de Dopamina D2/metabolismo , Potenciais de Ação/efeitos dos fármacos , Toxina Adenilato Ciclase , Animais , DNA Antissenso/farmacologia , Proteínas de Ligação ao GTP/antagonistas & inibidores , Transporte de Íons , Camundongos , Microscopia de Fluorescência , Microscopia de Vídeo , Proteínas de Neoplasias/fisiologia , Neoplasias Hipofisárias/patologia , Potássio/metabolismo , Potássio/farmacologia , Ligação Proteica , Isoformas de Proteínas/genética , Receptores de Dopamina D2/genética , Proteínas Recombinantes de Fusão/metabolismo , Transfecção , Células Tumorais Cultivadas , Fatores de Virulência de Bordetella/farmacologiaRESUMO
To define the stages in influenza haemagglutinin (HA)-mediated fusion the kinetics of fusion between cell pairs consisting of single influenza HA-expressing cells and single erythrocytes (RBC) which had been labelled with both a fluorescent lipid (Dil) in the membrane and a fluorescent solute (calcein) in the aqueous space have been monitored. It is shown that release of solute from the target cell occurs, following the formation of the hemi-fusion diaphragm. These results are discussed in terms of a model in which fusion peptide insertion into the target membrane induces lipid stalks, which results in the formation of a hemifusion diaphragm and a fusion pore. Bilayer expansion due to overproduction of these stalks can give rise to collateral damage of target membranes.
Assuntos
Hemaglutininas Virais/fisiologia , Fusão de Membrana , Orthomyxoviridae/fisiologia , Proteínas Virais de Fusão/fisiologia , Proteínas da Matriz Viral/fisiologia , Células 3T3 , Animais , Permeabilidade da Membrana Celular , Eritrócitos/virologia , Humanos , Camundongos , Modelos Biológicos , Fatores de TempoRESUMO
BACKGROUND: In a recent randomized intervention trial, the risk of prostate cancer for men receiving a daily supplement of 200 microg selenium was one third of that for men receiving placebo. By use of a nested case-control design within a prospective study, i.e., the Health Professionals Follow-Up Study, we investigated the association between risk of prostate cancer and prediagnostic level of selenium in toenails, a measure of long-term selenium intake. METHODS: In 1986, 51,529 male health professionals aged 40-75 years responded to a mailed questionnaire to form the prospective study. In 1987, 33,737 cohort members provided toenail clippings. In 1988, 1990, 1992, and 1994, follow-up questionnaires were mailed. From 1989 through 1994, 181 new cases of advanced prostate cancer were reported. Case and control subjects were matched by age, smoking status, and month of toenail return. Selenium levels were determined by neutron activation. All P values are two-sided. RESULTS: The selenium level in toenails varied substantially among men, with quintile medians ranging from 0.66 to 1.14 microg/g for control subjects. When matched case-control data were analyzed, higher selenium levels were associated with a reduced risk of advanced prostate cancer (odds ratio [OR] for comparison of highest to lowest quintile = 0.49; 95% confidence interval [CI] = 0.25-0.96; P for trend = .11). After additionally controlling for family history of prostate cancer, body mass index, calcium intake, lycopene intake, saturated fat intake, vasectomy, and geographical region, the OR was 0.35 (95% CI = 0.16-0.78; P for trend = .03). CONCLUSIONS: Our results support earlier findings that higher selenium intakes may reduce the risk of prostate cancer. Further prospective studies and randomized trials of this relationship should be conducted.
Assuntos
Unhas/química , Neoplasias da Próstata/química , Selênio/análise , Adulto , Idoso , Estudos de Casos e Controles , Humanos , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Razão de Chances , Neoplasias da Próstata/diagnóstico , Risco , Selênio/administração & dosagem , Inquéritos e Questionários , Dedos do PéRESUMO
We reviewed our experience over 3 years with 11 patients who had bile leaks (Group 1) and 8 patients who had bile duct strictures after laparoscopic cholecystectomy (LC) and were treated with endoscopic retrograde cholangiopancreatography (ERCP) (Group 2). In Group 1, bile leaks were at the level of the cystic duct in 10 patients and from a duct of Luschka in 1 patient; 10 patients had sphincterotomy and 11 patients received barbed stents. All patients had resolution of bile leak and stents were removed after an average of 5 weeks. In Group 2, stenoses were at the level of the common bile duct (CBD) in 7 patients and of the CBD-common hepatic duct in 1 patient. Six patients had a sphincterotomy and 7 patients were successfully treated with pneumatic polyethylene balloon dilatation and stent placement. One patient had unsatisfactory dilatation and was referred to surgery. Two patients had permanent resolution of stenosis at 3 and 4 years of follow-up, 5 patients had recurrence, and a total of 6 patients eventually needed surgery. We conclude that ERCP is effective in resolving isolated bile leaks, but iatrogenic strictures after LC more often require surgical treatment after ERCP.
Assuntos
Bile , Colangiopancreatografia Retrógrada Endoscópica , Colecistectomia Laparoscópica/efeitos adversos , Colestase/terapia , Complicações Pós-Operatórias/terapia , Cateterismo , Colestase/diagnóstico , Colestase/etiologia , Constrição Patológica , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Complicações Pós-Operatórias/diagnóstico , Radiografia Intervencionista , Esfinterotomia Endoscópica , StentsAssuntos
Cálcio/análise , Rim/química , Rim/citologia , Hipófise/química , Hipófise/citologia , Animais , Bradicinina/farmacologia , Cálcio/metabolismo , Cães , Células Epiteliais , Epitélio/química , Epitélio/metabolismo , Concentração de Íons de Hidrogênio , Rim/metabolismo , Masculino , Microscopia de Vídeo/métodos , Hipófise/metabolismo , Ratos , Ratos Sprague-Dawley , Fatores de Tempo , Vasoconstritores/farmacologiaRESUMO
Dopamine D2 receptor stimulation of cultured primary melanotropes was found to depress L-type calcium channel activity, whereas D2 receptor antagonist application increased it. When tested on culture days 10, 16, and 20, control cells displayed increasing rises of intracellular Ca2+ in response to K+ depolarization, indicating an increase in channel activity in the absence of dopaminergic regulation. When treated with 1 microM bromocriptine from culture day 1, cells showed minimal increase in channel activity. When bromocriptine was added on day 16, intracellular Ca2+ response to high K+ declined by day 20; removal of the agonist on day 16 resulted in the reappearance of increased responsiveness. Thus, in vitro inhibitions could be initiated or reversed with application or withdrawal of dopamine D2 receptor agonist. Cultured melanotropes were treated with antisense oligodeoxynucleotides directed against the start sequences of the D2 receptor and c-fos messenger RNA. D2 receptor antisense nucleotide prevented the depressive effect on channel activity induced by D2 agonist treatment. c-fos antisense oligodeoxynucleotide blocked the rise in channel activity. The dopamine D2 receptor antagonist haloperidol, which increased channel activity, could not reverse the c-fos antisense deoxynucleotide block. These results strongly support the idea that the chronic suppression of secretion-related activities by dopaminergic stimulation seen in the intermediate lobe in vivo is effected by chronic suppression of c-fos by D2 receptors.
Assuntos
Canais de Cálcio/metabolismo , Melanóforos/metabolismo , Hipófise/metabolismo , Proteínas Proto-Oncogênicas c-fos/metabolismo , Receptores de Dopamina D2/fisiologia , Animais , Sequência de Bases , Células Cultivadas , Primers do DNA , Masculino , Dados de Sequência Molecular , Ratos , Ratos Sprague-Dawley , Receptores de Dopamina D2/agonistasRESUMO
Three children presented with soft tissue masses which were clinically suspected to be soft tissue sarcomas. The identification of phleboliths on initial radiological studies should have suggested the correct diagnosis of benign intramuscular haemangiomata. Subsequent referral to a paediatric oncological unit, and the unnecessary parental anxiety so generated, could have been avoided.
Assuntos
Cálculos/diagnóstico por imagem , Hemangioma/diagnóstico por imagem , Sarcoma/diagnóstico por imagem , Neoplasias de Tecidos Moles/diagnóstico por imagem , Doenças Vasculares/diagnóstico por imagem , Criança , Pré-Escolar , Diagnóstico Diferencial , Feminino , Humanos , Masculino , Tomografia Computadorizada por Raios XRESUMO
During low pH-induced fusion of influenza virus with erythrocytes we have observed differential dispersion of viral lipid and haemagglutinin (HA) into the erythrocyte membrane, and viral RNA into the erythrocyte using fluorescence video microscopy. The movement of both viral lipid and HA from virus to cell was restricted during the initial stages of fusion relative to free diffusion. This indicates the existence of relatively long-lived barriers to diffusion subsequent to fusion pore formation. Fluorescence anisotropy of phospholipid analogues incorporated into the viral membrane decreased when the pH was lowered to levels required for optimum fusion. This indicates that the restricted motion of viral membrane components was not due to rigidification of membrane lipids. The movement of HA from the fusion site was also assessed by photosensitized labelling by means of a fluorescent substrate (NBD-taurine) passing through the band 3 sialoglycoprotein (the erythrocyte anion transporter). We also examined the flow of lipid and aqueous markers during fusion of HA-expressing cells with labelled erythrocytes. During this cell-cell fusion, movement of lipid between fusing membranes begins before the fusion pore is wide enough to allow diffusion of aqueous molecules (M(r) > 500). The data indicate that HA is capable of creating domains in the membrane and controlling continuity of aqueous compartments which are bounded by such domains.
Assuntos
Eritrócitos/virologia , Hemaglutininas/metabolismo , Orthomyxoviridae/química , Fusão Celular , Membrana Celular/química , Membrana Celular/metabolismo , Eritrócitos/citologia , Eritrócitos/metabolismo , Hemaglutininas/farmacologia , Humanos , Metabolismo dos Lipídeos , Microscopia de Vídeo , Orthomyxoviridae/metabolismo , Fármacos Fotossensibilizantes , Proteínas do Envelope Viral/metabolismo , Vírion/química , Vírion/metabolismoRESUMO
The Atlanta Project, one of six American Cancer Society demonstration projects, is a community-designed and -directed breast and cervical cancer screening program focused on empowering African-American women to accept responsibility for their health maintenance. This article reports the project's goals, objectives, intervention strategies, roles of key project personnel, and outcomes. A total of 3852 women older than 40 years received breast clinical examinations, were taught breast self-examination, and had a screening mammogram; 2689 women obtained a pelvic examination and were screened for cervical cancer with a Papanicolaou smear. Of those women screened, 12 breast and 1 cervical cancers were identified and treated. Important lessons learned and successes achieved from this project were: (1) there is a need for joint planning with community representatives and their involvement in all aspects of the program's implementation and evaluation; (2) in addition to the commitment of the major participants, the community must "buy in" to the proposed health intervention; (3) the focus of the intervention should be on positive health messages; (4) cancer education materials should be culturally and literacy-appropriate; (5) the project's activities were planned to be sustained after the project period; (6) women can be empowered to accept responsibility for and control over their health.
Assuntos
Negro ou Afro-Americano , Neoplasias da Mama/prevenção & controle , Serviços de Saúde Comunitária/organização & administração , Programas de Rastreamento/organização & administração , Neoplasias do Colo do Útero/prevenção & controle , Serviços de Saúde da Mulher/organização & administração , Adulto , Feminino , Humanos , Pessoa de Meia-Idade , Projetos PilotoRESUMO
The interrelationships between changes in intracellular calcium concentration ([Ca2+]i) and intracellular pH in Madin-Darby canine kidney cells and kidney glomerular epithelial cells exposed to various stimuli were analyzed simultaneously using a new design of a fluorescence video microscope. Cells were double labeled with indo 1 and SNARF 1 dyes and were excited simultaneously at 350 and 540 nm. Images at four emission wavelengths were captured simultaneously at 405, 475, 575, and 640 nm at 30 frames/s for the two ratio dyes. SNARF sensitivity to pH between 6.5 and 8.0 was unchanged by [Ca2+]i. The SNARF ratio maps were used to correct the pH-dependent changes in the calculation of local cell calcium. NH4Cl loading produced the expected alkalinization and a concurrent rise in [Ca2+]i. When the NH4Cl was removed and the cells became acidic, a second rise in [Ca2+]i was recorded. Both changes in [Ca2+]i were from intracellular stores since they persisted in the absence of extracellular calcium. The findings demonstrate the need for pH correction of indo 1 recordings.
Assuntos
Cálcio/metabolismo , Membranas Intracelulares/metabolismo , Glomérulos Renais/metabolismo , Rim/metabolismo , Cloreto de Amônio/farmacologia , Animais , Linhagem Celular , Células Epiteliais , Epitélio/metabolismo , Corantes Fluorescentes , Concentração de Íons de Hidrogênio , Indóis , Rim/citologia , Glomérulos Renais/citologia , Concentração OsmolarAssuntos
Fusão Celular/fisiologia , Eritrócitos/fisiologia , Hemaglutininas Virais/metabolismo , Proteínas do Envelope Viral/metabolismo , Células 3T3 , Animais , Linhagem Celular , Fibroblastos/fisiologia , Corantes Fluorescentes , Glicoproteínas de Hemaglutininação de Vírus da Influenza , Humanos , Vírus da Influenza A/fisiologia , Cinética , Camundongos , Oxidiazóis , Proteínas Recombinantes/metabolismo , Espectrometria de Fluorescência , Taurina/análogos & derivados , TermodinâmicaRESUMO
Plasmalogens (1-O-alk-1'-enyl-2-acyl-sn-glycero-3-phosphoethanolamine) are major phospholipids in many tissues and cells, particularly of neural origin. Using cultured C6 glioma cells and subcellular fractions isolated on Percoll gradients we investigated selectivity for esterification of several polyunsaturated fatty acids (PUFA) in the sn-2 position of plasmalogens compared to [1-14C]hexadecanol, representative of de novo synthesis of the ether-linked sn-1 position. In whole cells at a final concentration of 105 microM PUFA, 2-4 nmol plasmalogen/mg protein was labeled in 4 h and 10-14 nmol in 24 h, representing 8-15% and 35-50%, respectively, of initial plasmalogen mass. Incorporation of label from hexadecanol was lower than PUFA incorporation (20:5(n-3) greater than 20:4(n-6) greater than 18:3(n-3) much greater than 18:2(n-6)) suggesting deacylation-reacylation at the sn-2 position. Plasmalogens accounted for 50% of total cell ethanolamine phospholipids and 75% in plasma membrane. Using a novel, improved method for extraction of subcellular fractions containing Percoll, plasma membrane also was enriched in plasmalogen relative to microsomes (107.4 +/- 5.2 vs. 40.0 +/- 2.9 nmol/mg protein). Selectivity for esterification at the sn-2 position of plasmalogens with respect to chain length and unsaturation of the fatty acyl chain was similar in both subcellular fractions and reflected that of whole cells. Labeling of plasma membrane with PUFA and fatty alcohol lagged behind that of microsomes. Chase experiments in cells prelabeled with [1-14C]18:3(n-3) for 2 h showed no significant reduction of label in plasmalogen of any subcellular fraction although accumulation of label in the microsomal fraction was slowed initially. Reduction of plasmalogen label (40-50%) did occur in microsomes and plasma membrane when cells prelabeled for 24 h were switched to chase medium with or without chase fatty acid. Our data suggest that esterification of PUFA to plasmalogen may occur at the endoplasmic reticulum with subsequent translocation to plasma membrane resulting in accumulation of relatively stable pools of plasmalogen that are not readily accessible for deacylation-reacylation exchange with newly appearing PUFA. Alternatively, deacylation-reacylation may occur in a more stable phospholipid pool within the plasma membrane but would involve a slower process than at the endoplasmic reticulum.
Assuntos
Ácidos Graxos Insaturados/metabolismo , Glioma/metabolismo , Microssomos/metabolismo , Plasmalogênios/metabolismo , Acilação , Animais , Membrana Celular/metabolismo , Especificidade por Substrato , Células Tumorais CultivadasRESUMO
An educational program to promote screening through primary health care for the squamous cell cancers of the buccal cavity, pharynx, and larynx as developed and implemented, and its impact on screening was documented. Providers of care for high-risk patients at seven inner-city health care sites in Boston were identified and targeted for training. Of the 327 providers who were targeted for training from December 1986 through June 1989, 261 (80%) attended educational sessions. Screening exams were documented on an average of 14.7 patients per targeted provider through December 1989. The educational program was associated with a large increase in documented screening for these cancers, compared with baseline rates. Several adaptations in the program were required, including a demonstration of efficient screening to address the concerns of these providers about time constraints. Variations in the quantity and quality of documented screening among health care sites were noted.
Assuntos
Carcinoma de Células Escamosas/prevenção & controle , Neoplasias de Cabeça e Pescoço/prevenção & controle , Educação em Saúde , Boston , Carcinoma de Células Escamosas/epidemiologia , Estudos de Avaliação como Assunto , Neoplasias de Cabeça e Pescoço/epidemiologia , Educação em Saúde/organização & administração , Humanos , Incidência , Programas de Rastreamento , Atenção Primária à Saúde , Fatores de Risco , Saúde da População UrbanaRESUMO
An HPLC assay is described that can be used to study the covalent bonding interaction of carbinolamine-containing pyrrolo[2,1-c][1,4]benzodiazepines with the model nucleophile thiophenol, in order to evaluate electrophilicity at the C-11-position. Preliminary experiments with anthramycin, tomaymycin and neothramycin show that their reaction with thiophenol follows second-order kinetics, but the ranking order of reactivity (neothramycin greater than tomaymycin greater than anthramycin), does not correlate with either in vitro cytotoxicity or in vivo antitumour activity. This suggests that other factors such as non-covalent DNA-interaction or drug transport play a more crucial role in biological activity than simple alkylating ability. This assay should, however, prove a useful tool in the study of structure-activity relationships for this series of compounds and provide "C-11-electrophilicity" parameters for use in Hansch analysis and related studies.
Assuntos
Antramicina/química , Antibióticos Antineoplásicos/química , DNA/metabolismo , Fenóis/metabolismo , Compostos de Sulfidrila , Antramicina/metabolismo , Antibióticos Antineoplásicos/metabolismo , Benzodiazepinonas/química , Benzodiazepinonas/metabolismo , Cromatografia Líquida de Alta Pressão , Transporte de Elétrons , Cinética , Espectroscopia de Ressonância Magnética , Relação Estrutura-AtividadeRESUMO
The hypothesis that the small portion of cellular phosphoinositide participating in signal transduction might be preferentially recycled within the plasma membrane was tested in rat glioma (C6) and murine neuroblastoma (N1E-115) cells. Percoll density gradient centrifugation was used to isolate a purified plasma membrane fraction and the subcellular distribution of all enzymes mediating phosphoinositide turnover was assessed. A small but significant proportion of PtdInsP2-specific phosphodiesterase was located in the plasma membrane but only two of the five enzymes required to replace PtdInsP2 (diacylglycerol kinase and PtdInsP kinase) also were present. CTP:phosphatidate cytidylyltransferase and CMP-phosphatidate:inositol phosphatidyltransferase were located exclusively in a microsomal fraction containing enriched levels of endoplasmic reticulum markers. Thus, diacylglycerol from agonist-stimulated cleavage of PtdInsP2, or phosphatidic acid formed from it, must be transferred to the endoplasmic reticulum for conversion to PtdIns. Plasma membrane also lacked PtdIns kinase. If the soluble PtdIns kinase has access to membrane-bound substrate, PtdIns may be phosphorylated to PtdInsP before or during transport to the plasma membrane. Phosphorylation by the predominantly plasma membrane PtdInsP kinase to form PtdInsP2 completes the cycle. PtdInsP phosphatase was present in all membrane fractions suggesting that PtdInsP can be returned to the PtdIns pool in plasma membrane and elsewhere. PtdInsP2 phosphatase was almost exclusively in the cytosol suggesting that reversible interchange between PtdInsP and PtdInsP2 in the plasma membrane may be modulated by the ability of this phosphatase to act on PtdInsP2 in the membrane. Thus, PtdIns resynthesis in the plasma membrane of these cells does not occur and is not required for phosphoinositide-mediated signal transduction.