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1.
Ann Oncol ; 30(1): 96-102, 2019 01 01.
Artículo en Inglés | MEDLINE | ID: mdl-30335127

RESUMEN

Background: Multiple features in the presentation of randomized controlled trial (RCT) results are known to influence comprehension and interpretation. We aimed to compare interpretation of cancer RCTs with time-to-event outcomes when the reported treatment effect measure is the hazard ratio (HR), difference in restricted mean survival times (RMSTD), or both (HR+RMSTD). We also assessed the prevalence of misinterpretation of the HR. Methods: We carried out a randomized experiment. We selected 15 cancer RCTs with statistically significant treatment effects for the primary outcome. We masked each abstract and created three versions reporting either the HR, RMSTD, or HR+RMSTD. We randomized corresponding authors of RCTs and medical residents and fellows to one of 15 abstracts and one of 3 versions. We asked how beneficial the experimental treatment was (0-10 Likert scale). All participants answered a multiple-choice question about interpretation of the HR. Participants were unaware of the study purpose. Results: We randomly allocated 160 participants to evaluate an abstract reporting the HR, 154 to the RMSTD, and 155 to both HR+RMSTD. The mean Likert score was statistically significantly lower in the RMSTD group when compared with the HR group (mean difference -0.8, 95% confidence interval, -1.3 to -0.4, P < 0.01) and when compared with the HR+RMSTD group (difference -0.6, -1.1 to -0.1, P = 0.05). In all, 47.2% (42.7%-51.8%) of participants misinterpreted the HR, with 40% equating it with a reduction in absolute risk. Conclusion: Misinterpretation of the HR is common. Participants judged experimental treatments to be less beneficial when presented with RMSTD when compared with HR. We recommend that authors present RMST-based measures alongside the HR in reports of RCT results.


Asunto(s)
Neoplasias/mortalidad , Sistemas en Línea/estadística & datos numéricos , Ensayos Clínicos Controlados Aleatorios como Asunto , Terapia Combinada , Humanos , Neoplasias/patología , Neoplasias/terapia , Pronóstico , Tasa de Supervivencia , Factores de Tiempo
2.
HIV Med ; 18(4): 300-304, 2017 04.
Artículo en Inglés | MEDLINE | ID: mdl-27535357

RESUMEN

OBJECTIVES: European guidelines recommend HIV testing for individuals presenting with indicator conditions (ICs) including AIDS-defining conditions (ADCs). The extent to which non-HIV specialty guidelines recommend HIV testing in ICs and ADCs is unknown. Our aim was to pilot a methodology in the UK to review specialty guidelines and ascertain if HIV was discussed and testing recommended. METHODS: UK and European HIV testing guidelines were reviewed to produce a list of 25 ADCs and 49 ICs. UK guidelines for these conditions were identified from searches of the websites of specialist societies, the National Institute of Clinical Excellence (NICE) website, the NICE Clinical Knowledge Summaries (CKS) website, the Scottish Intercollegiate Guidance Network (SIGN) website and the British Medical Journal Best Practice database and from Google searches. RESULTS: We identified guidelines for 12 of 25 ADCs (48%) and 36 of 49 (73%) ICs. In total, 78 guidelines were reviewed (range 0-13 per condition). HIV testing was recommended in six of 17 ADC guidelines (35%) and 24 of 61 IC guidelines (39%). At least one guideline recommended HIV testing for six of 25 ADCs (24%) and 16 of 49 ICs (33%). There was no association between recommendation to test and publication year (P = 0.62). CONCLUSIONS: The majority of guidelines for ICs do not recommend testing. Clinicians managing ICs may be unaware of recommendations produced by HIV societies or the prevalence of undiagnosed HIV infection among these patients. We are piloting methods to engage with guideline development groups to ensure that patients diagnosed with ICs/ADCs are tested for HIV. We then plan to apply our methodology in other European settings as part of the Optimising Testing and Linkage to Care for HIV across Europe (OptTEST) project.


Asunto(s)
Infecciones por VIH/diagnóstico , Infecciones por VIH/epidemiología , Tamizaje Masivo/métodos , Guías de Práctica Clínica como Asunto , Humanos , Reino Unido
3.
Nat Genet ; 4(4): 410-4, 1993 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-8401591

RESUMEN

The autosomal Booroola fecundity gene (FecB) mutation in sheep increases ovulation rate and litter size, with associated effects on ovarian physiology and hormone profiles. Analysis of segregation in twelve families (379 female progeny) identified linkage between the mutation, two microsatellite markers (OarAE101 and OarHH55, Zmax > 9.0) and epidermal growth factor (EGF) from human chromosome 4q25 (Zmax > 3.0). The marker OarAE101 was linked to secreted phosphoprotein 1 (SPP1, which maps to chromosome 4q21-23 in man) in the test pedigrees and independent families (Zmax > 9.7). The identification of linkage between the FecB mutation and markers from human chromosome 4q is an important step towards further understanding the control of ovulation rates in mammals.


Asunto(s)
Mapeo Cromosómico , Cromosomas Humanos Par 4 , Fertilidad/genética , Mutación , Ovinos/genética , Animales , Secuencia de Bases , Sondas de ADN , ADN Satélite/genética , Femenino , Ligamiento Genético , Marcadores Genéticos , Genotipo , Humanos , Masculino , Datos de Secuencia Molecular , Oligodesoxirribonucleótidos , Fenotipo , Recombinación Genética
4.
Perspect Public Health ; 143(3): 173-178, 2023 May.
Artículo en Inglés | MEDLINE | ID: mdl-37132020

RESUMEN

AIMS: In recent years, there has been a growing interest in the ways that human health intersects with exposure to nature. This article reports the findings of a research study investigating the experiences of people in South and West Wales who were engaged in a specific type of nature and health intervention: ecotherapy. METHODS: Ethnographic methods were used to develop a qualitative account of the experiences of participants in four specific ecotherapy projects. Data collected during fieldwork included notes from participant observations, interviews with both individuals and small groups, and documents produced by the projects. RESULTS: Findings were reported using two themes: 'smooth and striated bureaucracy' and 'escape and getting away'. The first theme focused on how participants negotiated tasks and systems related to gatekeeping, registration, record keeping, rule compliance, and evaluation. It was argued that this was experienced differently along a spectrum between striated, in which it was disruptive to time and space, and smooth, in which it was much more discrete. The second theme reported on an axiomatic perception that natural spaces represented an escape or refuge; in terms of both reconnecting with something beneficial in nature, and also disconnecting from pathological aspects of everyday life. In bringing the two themes into dialogue, it could be seen that bureaucratic practices often undermined the therapeutic sense of escape; and that this was more acutely experienced by participants from marginalised social groups. CONCLUSIONS: This article concludes by reasserting that the role of nature in human health is contested and arguing for a greater emphasis on inequities in access to good quality green and blue space. Specific interventions like ecotherapy need funding models that avoid striated bureaucratic processes, and the stress associated with these. Inclusive models of ecotherapy practice could contribute to public health goals related to population engagement with healthy environments.


Asunto(s)
Salud Mental , Salud Pública , Humanos , Gales , Terapia por Relajación , Parques Recreativos
5.
Trials ; 22(1): 792, 2021 Nov 11.
Artículo en Inglés | MEDLINE | ID: mdl-34763711

RESUMEN

BACKGROUND: Alcohol consumption causes a spectrum of liver abnormalities and leads to over 3 million deaths per year. Alcoholic hepatitis (AH) is a florid presentation of alcoholic liver disease characterized by liver failure in the context of recent and heavy alcohol consumption. The aim of this study is to explore the potential benefits of the IL-1ß antibody, canakinumab, in the treatment of AH. METHODS: This is a multicentre, double-blind, randomised placebo-controlled trial. Participants will be diagnosed with AH using clinical criteria. Liver biopsy will then confirm that all histological features of AH are present. Up to 58 participants will be recruited into two groups from 15 centres in the UK. Patients will receive an infusion of Canakinumab or matched placebo by random 1:1 allocation. The primary outcome is the difference between groups in the proportion of patients demonstrating histological improvement and will compare histological appearances at baseline with appearances at 28 days to assign a category of "improved" or "not improved". Patients with evidence of ongoing disease activity will receive a second infusion of canakinumab or placebo. Participants will be followed up for 90 days. Secondary outcomes include mortality and change in MELD score at 90 days. DISCUSSION: This phase II study will explore the benefits of the IL-1ß antibody, canakinumab, in the treatment of AH to provide proof of concept that inhibition of IL-1ß signalling may improve histology and survival for patients with AH. TRIAL REGISTRATION: EudraCT 2017-003724-79 . Prospectively registered on 13 April 2018.


Asunto(s)
Hepatitis Alcohólica , Anticuerpos Monoclonales Humanizados , Ensayos Clínicos Fase II como Asunto , Método Doble Ciego , Hepatitis Alcohólica/diagnóstico , Hepatitis Alcohólica/tratamiento farmacológico , Humanos , Estudios Multicéntricos como Asunto , Ensayos Clínicos Controlados Aleatorios como Asunto , Resultado del Tratamiento
6.
J Exp Med ; 154(5): 1608-17, 1981 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-6975350

RESUMEN

We have investigated the induction of antibody responses to erythrocyte (RBC)-bound antigens in the (CBA/N x B10)F1 mouse. Male B cells, which express the CBA/N defect, were shown to be unresponsive to RBC antigens when the delivered T cell helper activity was solely nonspecific. Thus we demonstrated that defective B cells did not respond to concanavalin A supernatants or bystander helper activity, in spite of the fact that CBA/N-defective mice could produce these T cell activities. The defective B cell did not respond to RBC-bound antigen in the presence of RBC-primed T cells, although the magnitude of this response was usually twofold less than normal controls. The insensitivity of CBA/N defective B cells to nonspecific T cell helper activities seemed to involve at least the inability of RBC antigens to activate defective B cells in the absence of antigen-specific T cell help.


Asunto(s)
Linfocitos B/inmunología , Ratones Endogámicos CBA/genética , Aberraciones Cromosómicas Sexuales/inmunología , Linfocitos T/inmunología , Animales , Antígenos , Concanavalina A/biosíntesis , Concanavalina A/farmacología , Eritrocitos/inmunología , Femenino , Caballos , Síndromes de Inmunodeficiencia/genética , Síndromes de Inmunodeficiencia/inmunología , Masculino , Ratones , Perisodáctilos , Ovinos , Cromosoma X
7.
Growth Factors ; 28(3): 149-56, 2010 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-20102315

RESUMEN

Several studies have shown that bone morphogenetic proteins (BMPs) can influence adipogenic and osteogenic cell lineages. We have shown that a peptide derived from BMP-9 (pBMP-9) at 400 ng/ml inhibits the proliferation of preosteoblasts and induces differentiation. We have now determined the effects of pBMP-9 (400 ng/ml) and equimolar concentrations of BMP-2 (100 ng/ml), BMP-9 (84.6 ng/ml) and pBMP-9 (9.04 ng/ml) on human white preadipocytes (HWP). pBMP-9 dose dependently reduced the proliferation of HWP without affecting the number of apoptotic cells. Incubation of the cells for 1 h with BMP-2, BMP-9 or pBMP-9 activated the Smad1/5/8 pathway, while incubation for 7 days in adipocyte differentiation (AD) serum-free medium containing ciglitazone and equimolar concentrations of BMP-2, BMP-9 or pBMP-9 enhanced the levels of mRNA of the adipogenic markers aP2 and adipoQ and increased the number of lipid vesicles. Thus, pBMP-9, like BMP-9, can increase the AD of HWP in AD serum-free medium.


Asunto(s)
Adipocitos Blancos/efectos de los fármacos , Adipogénesis/efectos de los fármacos , Factores de Diferenciación de Crecimiento/farmacología , Adipocitos Blancos/fisiología , Adulto , Proteína Morfogenética Ósea 2/farmacología , Proliferación Celular/efectos de los fármacos , Femenino , Marcadores Genéticos , Factor 2 de Diferenciación de Crecimiento , Humanos , Osteogénesis/efectos de los fármacos , PPAR gamma/análisis , Péptidos/farmacología , Proteínas Smad/efectos de los fármacos , Tiazolidinedionas/farmacología
8.
Sci Rep ; 10(1): 8901, 2020 06 01.
Artículo en Inglés | MEDLINE | ID: mdl-32483316

RESUMEN

Guinea pigs (Cavia spp.) have a long association with humans. From as early as 10,000 years ago they were a wild food source. Later, domesticated Cavia porcellus were dispersed well beyond their native range through pre-Columbian exchange networks and, more recently, widely across the globe. Here we present 46 complete mitogenomes of archaeological guinea pigs from sites in Peru, Bolivia, Colombia, the Caribbean, Belgium and the United States to elucidate their evolutionary history, origins and paths of dispersal. Our results indicate an independent centre of domestication of Cavia in the eastern Colombian Highlands. We identify a Peruvian origin for the initial introduction of domesticated guinea pigs (Cavia porcellus) beyond South America into the Caribbean. We also demonstrate that Peru was the probable source of the earliest known guinea pigs transported, as part of the exotic pet trade, to both Europe and the southeastern United States. Finally, we identify a modern reintroduction of guinea pigs to Puerto Rico, where local inhabitants use them for food. This research demonstrates that the natural and cultural history of guinea pigs is more complex than previously known and has implications for other studies regarding regional to global-scale studies of mammal domestication, translocation, and distribution.


Asunto(s)
ADN Antiguo/análisis , ADN Mitocondrial/análisis , Cobayas/clasificación , Mitocondrias/genética , Análisis de Secuencia de ADN/veterinaria , Animales , Bélgica , Bolivia , Colombia , Domesticación , Evolución Molecular , Cobayas/genética , Perú , Filogenia , Filogeografía , Dinámica Poblacional , Puerto Rico , Estados Unidos
10.
Science ; 243(4898): 1606-8, 1989 Mar 24.
Artículo en Inglés | MEDLINE | ID: mdl-17847262

RESUMEN

The secretory matrix of the stylar-transmitting tract of angiosperms has been characterized as a nutrient medium for the growth of pollen tubes, acting to guide tubes to the ovules. When nonliving particles (latex beads) were artificially introduced onto the transmitting tracts of styles of Hemerocallis flava, Raphanus raphanistrum, and Vicia faba, they were translocated to the ovary at rates similar to those of pollen tubes. Direct observations were made on the movement of individual beads along the secretory epidermis in the style and ovary of Vicia faba. The transmitting tract may play an active role in extending tube tips to their destination in the ovary.

11.
Science ; 223(4637): 695-6, 1984 Feb 17.
Artículo en Inglés | MEDLINE | ID: mdl-17841029

RESUMEN

The cleistogamous species Collomia grandiflora produces dimorphic cross-incompatible flowers on a single plant. The open or chasmogamous flower has smaller, flask-shaped stigmatic papillae, larger pollen grains, longer styles, and faster pollen tube growth rates down the style than the closed or cleistogamous flower. In intermorph crosses, pollen tube growth rates are greatly decreased and fertilization does not occur.

12.
Science ; 229(4717): 969-71, 1985 Sep 06.
Artículo en Inglés | MEDLINE | ID: mdl-17782529

RESUMEN

Observations of malic acid fluctuation, leaf anatomy, and stable carbon isotopic composition showed that the epiphytic strangler Clusia rosea, growing on Saint John, U.S. Virgin Islands, has crassulacean acid metabolism. This hemiepiphyte may be the only woody dicotyledonous tree species among the many thousands of flowering species in the 30 or more plant families that shows this type of metabolism. The finding has implications with respect to water balance during the process whereby Clusia rosea establishes itself as a tree, since crassulacean acid metabolism is a photosynthetic adaptation to water-stressed environments.

13.
J Clin Invest ; 100(6): 1363-72, 1997 Sep 15.
Artículo en Inglés | MEDLINE | ID: mdl-9294101

RESUMEN

Significant numbers of myocytes die by apoptosis during myocardial infarction. The molecular mechanism of this process, however, remains largely unexplored. To facilitate a molecular genetic analysis, we have developed a model of ischemia-induced cardiac myocyte apoptosis in the mouse. Surgical occlusion of the left coronary artery results in apoptosis, as indicated by the presence of nucleosome ladders and in situ DNA strand breaks. Apoptosis occurs mainly in cardiac myocytes, and is shown for the first time to be limited to hypoxic regions during acute infarction. Since hypoxia-induced apoptosis in other cell types is dependent on p53, and p53 is induced by hypoxia in cardiac myocytes, we investigated the necessity of p53 for myocyte apoptosis during myocardial infarction. Myocyte apoptosis occurs as readily, however, in the hearts of mice nullizygous for p53 as in wild-type littermates. These data demonstrate the existence of a p53-independent pathway that mediates myocyte apoptosis during myocardial infarction.


Asunto(s)
Apoptosis , Genes p53/fisiología , Infarto del Miocardio/patología , Miocardio/patología , Animales , Hipoxia de la Célula , ADN/análisis , Genes p53/genética , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Factores de Tiempo
14.
Plant Cell ; 3(6): 629-635, 1991 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-12324606

RESUMEN

The extracellular matrix (ECM) has been implicated in the primary developmental processes of many organisms. A family of secretory adhesive glycoproteins called substrate adhesion molecules (SAMs) is believed to confer these dynamic capabilities to the ECM in animals. In this paper, we report the existence of SAM-like genes and gene products in flowering plants. Hybridizations with a human vitronectin cDNA probe and genomic DNA from broad bean, soybean, and tomato revealed vitronectin-like sequences. Human vitronectin antibodies cross-react with a 55-kilodalton protein in leaf and root protein extracts from lily, broad bean, soybean, and tomato. In addition, immunocytochemical staining of frozen sections of lily leaf and broad bean gynoecium demonstrated that vitronectin-like proteins were localized to the ECM on the cell surface, with the most intense labeling residing in the transmitting tract of broad bean gynoecium.

15.
Acta Crystallogr A ; 63(Pt 1): 1-10, 2007 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-17179602

RESUMEN

The problems of redundancy and superfluous indices in indexing the planes and axes in a decagonal quasicrystal are considered, using a scheme of five coplanar vectors in the quasiperiodic plane and one perpendicular vector. Of all the indexing schemes in use, this scheme offers the maximum advantage. An analogy is drawn to the hexagonal system using Miller-Bravais indices. Based on this, a symmetry-based indexing system for decagonal phases is devised that follows a simplified approximate zone law analogous to the exact zone law for the hexagonal case. The indices based on this scheme will be designated as ;Frank indices'. High-symmetry electron diffraction zone-axis patterns as well as powder X-ray diffraction patterns are indexed using Frank indices and compared with those of other indexing schemes.


Asunto(s)
Aleaciones/química , Cristalografía por Rayos X/métodos , Aluminio/química , Cobalto/química , Cobre/química , Cristalización
16.
Injury ; 48(10): 2248-2252, 2017 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-28712488

RESUMEN

INTRODUCTION: Two-stage limb reconstruction is an option for patients with critical size segmental bone defects following acute trauma or non-union. Reconstruction is technically demanding and associated with a high complication rate. Current protocols for limb reconstruction have well-documented challenges, and no study has reported on patient outcomes using a validated questionnaire. In this study, we aimed to examine the clinical and patient-centered outcomes following our surgical protocol for two-stage limb reconstruction following critical size segmental defects. PATIENTS AND METHODS: A single surgeon performed reconstruction of long bone defects using antibiotic impregnated cement spacers and intramedullary cancellous bone autograft. A retrospective chart review was performed. Three reviewers independently measured time to union based on radiographs. The Lower Extremity Functional Scale (LEFS) survey was administered to patients after most recent follow-up. RESULTS: Ten limbs representing nine patients were included. All patients sustained a lower extremity injury, and one patient had bilateral lower extremity injuries. Average clinical follow-up was 18.3 months (range 7-33) from final surgical intervention, and follow-up to questionnaire administration was 28 months (range 24-37). The mean time between stages was 3.1 months. Average time to unrestricted weight-bearing was 7.9 months from Stage 1 (range 3.4-15.9) and 4.5 months from Stage 2 (range 1.1-11.6). Average time to full union was 16.7 months from Stage 1 (range 6.4-28.6) and 13.5 months from Stage 2 (range 1.8-27). Eight patients (nine limbs) participated in the LEFS survey, the average score was 53.1 (range 30-67), equating to 66% of full functionality (range 38%-84%). Complications included 5 infections, 3 non-unions, and one amputation. There was a moderate positive correlation between infection at any time point and non-union (R=0.65, p=0.03). DISCUSSION AND CONCLUSIONS: Outcomes in this small patient cohort were good despite risks of complication. There is an association between infection and non-union. Further studies addressing clinical and functional outcomes will help to guide expectations for future surgeons and patients.


Asunto(s)
Trasplante Óseo , Diáfisis/cirugía , Fracturas del Fémur/cirugía , Fijación Interna de Fracturas , Fracturas Conminutas/cirugía , Fracturas no Consolidadas/cirugía , Infección de la Herida Quirúrgica/terapia , Fracturas de la Tibia/cirugía , Adulto , Antibacterianos , Cementos para Huesos , Protocolos Clínicos , Terapia Combinada , Diáfisis/patología , Femenino , Fracturas del Fémur/complicaciones , Fracturas del Fémur/fisiopatología , Estudios de Seguimiento , Curación de Fractura , Fracturas Conminutas/complicaciones , Fracturas Conminutas/fisiopatología , Fracturas no Consolidadas/fisiopatología , Humanos , Masculino , Persona de Mediana Edad , Medición de Resultados Informados por el Paciente , Reoperación , Estudios Retrospectivos , Fracturas de la Tibia/complicaciones , Fracturas de la Tibia/fisiopatología , Adulto Joven
17.
Trends Plant Sci ; 5(9): 368-73, 2000 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-10973091

RESUMEN

Pollination involves an interaction between the female tissues (stigma, style and ovary) and the male gametophyte or the pollen tube cell, which contains the sperm cells. Freezing methods now allow us to visualize the extracellular matrices that guide pollen tubes to the ovary. Adhesion of the pollen tube to these specialized extracellular matrices might be a mechanism of guidance and tube cell movement in the style. In lily, the stylar adhesion molecules are a pectin and a small, basic cysteine-rich protein, both of which are necessary to induce tube cell adhesion to an artificial, in vitro style matrix.


Asunto(s)
Movimiento Celular , Liliaceae/fisiología , Polen/fisiología , Secuencia de Aminoácidos , Adhesión Celular , Corriente Citoplasmática , Liliaceae/citología , Liliaceae/ultraestructura , Datos de Secuencia Molecular , Epidermis de la Planta/fisiología , Epidermis de la Planta/ultraestructura , Polen/crecimiento & desarrollo , Polen/ultraestructura , Reproducción
18.
Cancer Res ; 45(12 Pt 1): 6362-5, 1985 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-3877567

RESUMEN

Dimethyl sulfoxide (DMSO) has previously been shown to increase the surface expression of H-2K and H-2D antigens on cultured line 1 carcinoma cells. H-2 densities increase from initial levels barely detectable with flow cytometry to those found on normal BALB/c spleen cells. Here we compare the susceptibilities of untreated and DMSO-treated line 1 cells to lysis mediated by H-2d specific monoclonal antibodies and complement, cytotoxic T-cells, and natural killer cells. Induced H-2 antigens appear to function normally in that DMSO-treated cells are highly susceptible to all types of H-2 restricted immune lysis, whereas untreated line 1 cells are not. DMSO does not increase lysis of line 1 cells mediated by natural killer cells. Our results suggest that DMSO could be used to make the growth of major histocompatibility complex antigen-deficient tumors more sensitive to T-cell-mediated immunological resistance.


Asunto(s)
Carcinoma/inmunología , Dimetilsulfóxido/farmacología , Antígenos H-2/inmunología , Neoplasias Pulmonares/inmunología , Animales , Antígenos de Neoplasias/inmunología , Citotoxicidad Inmunológica/efectos de los fármacos , Isoanticuerpos/inmunología , Células Asesinas Naturales/inmunología , Ratones , Linfocitos T/inmunología
19.
Cancer Res ; 53(23): 5721-6, 1993 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-8242628

RESUMEN

Hypoxic cells in tissue pose many medical problems, and there is a need for more accurate measurements of tissue hypoxia. However, measurement of the pO2 and the extent of hypoxia within normal and tumor tissue have proven difficult. One of the most sensitive of the currently available methodologies involves the oxygen-dependent metabolic activation of nitroheterocyclic drugs, leading to adducts between the drugs and cellular macromolecules. Limitations of the present drugs and adduct-detection methods prompted the present studies. A pentafluorinated derivative [EF5; 2-(2-nitro-1H-imidazol-1-yl)-N-(2,2,3,3,3-pentafluoropropyl)acetam ide] of etanidazole was synthesized with the expectation of lessening some of the non-oxygen-dependent variability in adduct formation observed previously with other nitroaromatic compounds. EF5-protein conjugates, prepared by radiochemical reduction, were found to be immunogenic and allowed the development of monoclonal antibodies. One of these antibodies, ELK2-4, has been characterized and found to be highly specific for the EF5 adducts whether produced radiochemically or by cellular bioreductive metabolism. 9L rat glioma cells pretreated with EF5 under hypoxic, compared with aerobic, conditions were readily discriminated immunochemically using fluorochrome-conjugated secondary antibodies which recognize the ELK2-4 antibody subtype (IgG1). Similarly, the central region of multicenter spheroids, composed of EMT6 mouse mammary sarcoma cells, was selectively visualized by immunohistochemistry after the spheroids were incubated for 4 h in 0.5 mM EF5. Tumor biopsy, preparation, and immunohistochemical staining 24 h after treatment of tumor-bearing animals with drug also demonstrated high contrast regions within EMT6 mouse or Morris 7777 hepatoma rat tumors. The use of this new compound and its highly specific monoclonal antibody may allow elucidation of bioreductive metabolism of the nitroheterocyclics and significantly improve technologies for the quantitation of tissue pO2.


Asunto(s)
Anticuerpos Monoclonales , Hipoxia de la Célula , Etanidazol/análogos & derivados , Nitroimidazoles/metabolismo , Animales , Etanidazol/síntesis química , Ratones , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Nitroimidazoles/inmunología
20.
Cancer Res ; 44(8): 3317-23, 1984 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-6378365

RESUMEN

Previous reports have established that line 1, a spontaneous BALB/c lung carcinoma, expresses a Mr 180,000 tumor-associated surface antigen (TSP-180). In this study, using a monoclonal antibody and flow cytometry to quantify cell surface TSP-180 expression, we found that essentially all cells in a tissue culture-adapted line 1 population express TSP-180, but that the amount of TSP-180 expressed by cells is quite heterogeneous. Variation in amount of TSP-180 was found to be in part related to cell size heterogeneity, and to the expression of TSP-180 being cell cycle-dependent. The amount of surface-expressed TSP-180 correlated somewhat with cell size, and was greater on the average for cells in the G2 cell cycle compartment. However, cells of a defined size and specific cell cycle stage still showed marked heterogeneity of expression. Even though the average amount of TSP-180 expressed per cell decreased during in vitro propagation, little change in heterogeneity was observed. To explore whether any TSP-180-related heterogeneity resulted from heritable variation of expression, 263 limiting dilution-derived line 1 clones were analyzed. The majority displayed, shortly after cloning, heterogeneous TSP-180 profiles and mean TSP-180 levels similar to those observed for the parent tumor. Occasionally, however, clones were isolated that again appeared as heterogeneous as the parent, but differed by as much as 3-fold in mean TSP-180 expression. Extensive passage did not substantially increase the low probability of isolating clones which differed in expression of TSP-180. Differences in TSP-180 expression among clones were found to be relatively stable upon passage, typically maintained after recloning, and large enough to influence clonal susceptibility to TSP-180-directed antibody and complement-mediated lysis. Heritable variation in TSP-180 expression among some clones was also shown to be independent of differences related to cell size, cell cycle, or expression of another line 1 surface antigen (P-100). We concluded that although clones demonstrating large heritable differences in TSP-180 expression can occasionally be isolated, line 1 TSP-180 heterogeneity is predominantly nonheritable, being similar to that present in recently cloned lines, quite stable during in vitro passage, and not totally accounted for by cell cycle or cell size variation.


Asunto(s)
Antígenos de Neoplasias/análisis , Antígenos de Superficie/análisis , Neoplasias Pulmonares/inmunología , Animales , Anticuerpos Monoclonales , Ciclo Celular , Línea Celular , Membrana Celular/inmunología , Células Clonales , Citometría de Flujo , Técnica del Anticuerpo Fluorescente , Cinética , Ratones , Ratones Endogámicos BALB C , Peso Molecular
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