RESUMO
The endothelial glycocalyx, a gel-like layer that lines the luminal surface of blood vessels, is composed of proteoglycans, glycoproteins, and glycosaminoglycans. The endothelial glycocalyx plays an essential role in vascular homeostasis, and its degradation in trauma and sepsis can lead to microvascular dysfunction and organ injury. While there are no proven therapies for preventing or treating endothelial glycocalyx degradation, some initial literature suggests that plasma may have a therapeutic role in trauma and sepsis patients. Overall, the literature suggesting the use of plasma as a therapy for endothelial glycocalyx degradation is non-clinical basic science or exploratory. Plasma is an established therapy in the resuscitation of patients with hemorrhage for restoration of coagulation factors. However, plasma also contains other bioactive components, including sphingosine-1 phosphate, antithrombin, and adiponectin, which may protect and restore the endothelial glycocalyx, thereby helping to maintain or restore vascular homeostasis. This narrative review begins by describing the endothelial glycocalyx in health and disease: we discuss the overlapping disease mechanisms in trauma and sepsis that lead to its damage and introduce plasma transfusion as a potential therapy for prevention and treatment of endothelial glycocalyx degradation. Second, we review the literature on plasma as an exploratory therapy for endothelial glycocalyx degradation in trauma and sepsis. Third, we discuss the safety of plasma transfusion by reviewing the adverse events associated with plasma and other blood product transfusions, and we examine modern transfusion precautions that have enhanced the safety of plasma transfusion. We conclude that the literature proposes that plasma may have the potential to prevent and treat endothelial glycocalyx degradation in trauma and sepsis, indicating the need for further research.
Assuntos
Glicocálix , Plasma , Sepse , Ferimentos e Lesões , Glicocálix/metabolismo , Glicocálix/fisiologia , Humanos , Sepse/terapia , Sepse/fisiopatologia , Ferimentos e Lesões/terapia , Ferimentos e Lesões/complicações , Plasma/metabolismo , Endotélio Vascular/metabolismo , Endotélio Vascular/fisiopatologiaRESUMO
The goal of hemodynamic resuscitation is to optimize the microcirculation of organs to meet their oxygen and metabolic needs. Clinicians are currently blind to what is happening in the microcirculation of organs, which prevents them from achieving an additional degree of individualization of the hemodynamic resuscitation at tissue level. Indeed, clinicians never know whether optimization of the microcirculation and tissue oxygenation is actually achieved after macrovascular hemodynamic optimization. The challenge for the future is to have noninvasive, easy-to-use equipment that allows reliable assessment and immediate quantitative analysis of the microcirculation at the bedside. There are different methods for assessing the microcirculation at the bedside; all have strengths and challenges. The use of automated analysis and the future possibility of introducing artificial intelligence into analysis software could eliminate observer bias and provide guidance on microvascular-targeted treatment options. In addition, to gain caregiver confidence and support for the need to monitor the microcirculation, it is necessary to demonstrate that incorporating microcirculation analysis into the reasoning guiding hemodynamic resuscitation prevents organ dysfunction and improves the outcome of critically ill patients.
Assuntos
Cuidados Críticos , Microcirculação , Ressuscitação , Cuidados Críticos/tendências , Hemodinâmica , Inteligência ArtificialRESUMO
Three morphologically similar thermo-acidophilic strains, USBA-GBX-501, USBA-GBX-502 and USBA-GBX-503T, were isolated from acidic thermal springs at the National Natural Park Los Nevados (Colombia). All isolates were spore-forming, Gram-stain-positive and motile, growing aerobically at 25-55 °C (optimum ~45 °C) and at pH 1.5-4.5 (optimum pH ~3.0). Phylogenetic analysis of the 16S rRNA gene sequences of these isolates showed an almost identical sequence (99.0â% similarity) and they formed a robust cluster with the closest relative Alicyclobacillus tolerans DSM 16297T with a sequence similarity of 99.0â%. Average similarity to other species of the genus Alicyclobacillus was 93.0â% and average similarity to species of the genus Effusibacillus was 90â%. In addition, the level of DNA-DNA hybridization between strain USBA-GBX-503T and Alicyclobacillus tolerans DSM 16297T was 31.7â%. The genomic DNA G+C content of strain USBA-GBX-503T was 44.6 mol%. The only menaquinone was MK-7 (100.0â%). No ω-alicyclic fatty acids were detected in strain USBA-GBX-503T, and the major cellular fatty acids were C18â:â1ω7c, anteiso-C17â:â0 and iso-C17â:â0. Based on phenotypic and chemotaxonomic characteristics, phylogenetic analysis and DNA-DNA relatedness values, along with low levels of identity at the whole genome level (ANIb and ANIm values of <67.0 and <91.0â%, respectively), it can be concluded that strain USBA-GBX-503T represents a novel species of the genus Alicyclobacillus, for which the name Alicyclobacillus montanus sp. nov. is proposed. The type strain is USBA-GBX-503T (=CMPUJ UGB U503T=CBMAI1927T).
Assuntos
Alicyclobacillus/classificação , Fontes Termais/microbiologia , Filogenia , Alicyclobacillus/genética , Alicyclobacillus/isolamento & purificação , Técnicas de Tipagem Bacteriana , Composição de Bases , Colômbia , DNA Bacteriano/genética , Ácidos Graxos/química , Hibridização de Ácido Nucleico , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Vitamina K 2/análogos & derivados , Vitamina K 2/químicaRESUMO
We present an analysis of the Mw = 5.3 earthquake that occurred in the Southeast Indian Ridge on 2010 February 11 using USArray data. The epicentre of this event is antipodal to the USArray, providing us with an opportunity to observe in details the antipodal focusing of seismic waves in space and time. We compare the observed signals with synthetic seismograms computed for a spherically symmetric earth model (PREM). A beamforming analysis is performed over the different seismic phases detected at antipodal distances. Direct spatial snapshots of the signals and the beamforming results show that the focusing is well predicted for the first P-wave phases such as PKP or PP. However, converted phases (SKSP, PPS) show a deviation of the energy focusing to the south, likely caused by the Earth's heterogeneity. Focusing of multiple S-wave phases strongly deteriorates and is barely observable.
RESUMO
AIMS/HYPOTHESIS: Several endothelial pathways of cell adhesion, coagulation and vascular endothelial growth factor (VEGF) signalling are activated during sepsis. The objective of this analysis was to investigate the influence of diabetes on biomarkers of endothelial cell activation in sepsis. METHODS: This was a prospective observational cohort study of a convenience sample of adult patients (age ≥ 18 years) for whom infection was clinically suspected and who presented to an urban tertiary care emergency department between February 2005 and November 2008. We investigated the association of diabetes and sepsis with various endothelial activation biomarkers of cell adhesion (E-selectin, vascular cell adhesion molecule 1 [VCAM-1] and intercellular adhesion molecule 1 [ICAM-1]), coagulation (plasminogen activator inhibitor 1 [PAI-1]) and VEGF signalling (soluble fms-like tyrosine kinase-1 [sFLT-1]). RESULTS: A total of 207 patients (34% with sepsis, 32% with severe sepsis and 34% with septic shock) were studied, including 63 (30%) with diabetes. Compared with patients without diabetes, patients with diabetes had significantly increased E-selectin and sFLT-1 levels overall; this was most pronounced during septic shock in the stratified analysis. Multivariate models including age, sex, sepsis severity and other variables as potential covariates confirmed the association of diabetes with elevated circulating plasma levels of E-selectin (standardised ß 0.24, p < 0.001) and sFLT-1 (standardised ß 0.19, p < 0.01), but there was no significant association with VCAM-1, ICAM-1 or PAI-1. CONCLUSIONS/INTERPRETATION: During septic shock, patients with diabetes had higher levels of circulating biomarkers of endothelial cell adhesion (E-selectin) and VEGF signalling (sFLT-1). Future studies should address whether enhanced activation of the endothelium places patients with diabetes at increased risk for the development of sepsis and worsening morbidity and mortality.
Assuntos
Diabetes Mellitus/metabolismo , Endotélio Vascular/metabolismo , Sepse/metabolismo , Idoso , Diabetes Mellitus/fisiopatologia , Selectina E/metabolismo , Ensaio de Imunoadsorção Enzimática , Feminino , Humanos , Molécula 1 de Adesão Intercelular/metabolismo , Masculino , Pessoa de Meia-Idade , Inibidor 1 de Ativador de Plasminogênio/metabolismo , Estudos Prospectivos , Molécula 1 de Adesão de Célula Vascular/metabolismo , Fator A de Crescimento do Endotélio Vascular/metabolismo , Receptor 1 de Fatores de Crescimento do Endotélio Vascular/metabolismoRESUMO
The paper describes the trend in the spread of pandemic influenza A(H1N1) swl virus in the Far East, which started in this region 2-3 months later than that in the European part of Russia. By mid-October seasonal epidemic influenza was practically displaced by pandemic one.
Assuntos
Surtos de Doenças , Vírus da Influenza A Subtipo H1N1/classificação , Influenza Humana/epidemiologia , Animais , Anticorpos Antivirais/sangue , Linhagem Celular , Embrião de Galinha , Cães , Monitoramento Ambiental , Monitoramento Epidemiológico , Humanos , Vírus da Influenza A Subtipo H1N1/imunologia , Vírus da Influenza A Subtipo H1N1/isolamento & purificação , Influenza Humana/sangue , Influenza Humana/diagnóstico , Influenza Humana/virologia , Sibéria/epidemiologiaRESUMO
Results of examination and treatment of 3794 patients with nodular formations of the thyroid gland were analyzed. All the operations were followed by cytological investigation of the intraoperation scrape whose results determined the indications to urgent histological investigation. It was shown that the data of intraoperative cytological and histological diagnostics were comparable, the cytological diagnosis of atypical adenoma being an indication to urgent histological investigation. Urgent cytological investigations make the detection of thyroid cancer 2 times higher and risk of reoperations 10 times less at this nozology. The data obtained demonstrate effectiveness of the intraoperative cytological investigation in the present-day diagnostics of pretumor diseases and tumors of the thyroid gland.
Assuntos
Biópsia por Agulha/métodos , Monitorização Intraoperatória/métodos , Lesões Pré-Cancerosas , Glândula Tireoide/patologia , Neoplasias da Glândula Tireoide/patologia , Tireoidectomia , Diagnóstico Diferencial , Humanos , Estudos Retrospectivos , Glândula Tireoide/diagnóstico por imagem , Glândula Tireoide/cirurgia , Neoplasias da Glândula Tireoide/diagnóstico por imagem , Neoplasias da Glândula Tireoide/cirurgia , UltrassonografiaRESUMO
OBJECTIVE: To compare bleeding complications in pregnant patients treated with low-molecular-weight heparin (LMWH) to untreated controls. STUDY DESIGN: A case-control study of patients from 2001 to 2005 who received prophylactic or therapeutic doses of LMWH during pregnancy was carried out. Indications for LMWH included current or prior thromboembolism, thrombophilia, or heart valve replacement. Controls were chosen in a 2:1 ratio to cases, matched for delivery route, and selected as the next two consecutive deliveries. The primary outcome was postpartum hemorrhage (PPH). Odds ratios (ORs) were calculated with 95% confidence intervals (CIs). RESULTS: Forty-nine women treated with LMWH delivered 55 infants. Current or prior thromboembolic disease was the anticoagulation indication in 15/55 (27.3%) and 26/55 (47%) of pregnancies, respectively. There were more obese gravidas (OR 3.91, CI 1.70 to 9.09) and labor induction was more common in the LMWH group, 25/55 (45%) vs 29/110 (26%), P=0.01. There was no difference in estimated blood loss (295.7+/-145.7 vs 308.6+/-111.9 cm(3), P=0.62 vaginal; 687.5+/-251.8 vs 765.0+/-313.2 cm(3), P=0.34 cesarean), PPH (6/55, 11% vs 9/110, 8.2% OR 1.37, CI 0.16 to 11.5) or transfusion (3/55, 5.4% vs 4/110, 3.6% OR 1.50, CI 0.3 to 7.48) between the cases and controls. There were two cases of postpartum pulmonary emboli, one with a maternal mortality. CONCLUSION: Bleeding complications, including PPH and transfusion, in patients treated with LMWH during pregnancy were not increased when compared to normal controls matched for delivery route.
Assuntos
Anticoagulantes/efeitos adversos , Heparina de Baixo Peso Molecular/efeitos adversos , Hemorragia Pós-Parto/epidemiologia , Complicações Cardiovasculares na Gravidez/prevenção & controle , Tromboembolia/prevenção & controle , Adulto , Anticoagulantes/administração & dosagem , Estudos de Casos e Controles , Feminino , Heparina de Baixo Peso Molecular/administração & dosagem , Humanos , Illinois/epidemiologia , Recém-Nascido , Hemorragia Pós-Parto/induzido quimicamente , Gravidez , Resultado da Gravidez , Fatores de RiscoRESUMO
The surviving sepsis campaign developed guidelines in 2003 that were designed to increase physician awareness of sepsis and to develop a series of recommendations for the management of the patient with sepsis. The guidelines had the support of 11 international professional organisations across a variety of specialties, and advocate aggressive, early goal-oriented resuscitation in appropriate patients.
Assuntos
Medicina de Emergência/métodos , Oxigenoterapia , Sepse/prevenção & controle , Transfusão de Sangue , Cateterismo , Protocolos Clínicos , Emergências , Hidratação , Humanos , Seleção de Pacientes , Ressuscitação/métodos , Reino Unido , Vasodilatadores/uso terapêuticoRESUMO
Raoultella terrigena R1Gly is a diazotrophic endophyte isolated from surface-sterilized roots of Nicotiana tabacum. The whole-genome sequence was obtained to investigate the endophytic characteristics of this organism at the genetic level, as well as to compare this strain with its close relatives. To our knowledge, this is the first genome obtained from the Raoultella terrigena species and only the third genome from the Raoultella genus, after Raoultella ornitholytic and Raoultella planticola. This genome will provide a foundation for further comparative genomic, metagenomic, and functional studies of this genus.
RESUMO
It has been proposed that an adenovirus with the E1b-55kD gene deleted has a selective advantage in replicating in cancer cells that have mutations in the p53 gene (Bischoff et al., 1996). We have explored this hypothesis in several lung cancer cell lines, and evaluated potential mechanisms that might regulate the replication of Ad338, an E1b-55kD-deleted virus, with the objective of developing a rational approach for targeting gene therapy to lung tumors. Our data show that Ad338 replicates poorly in three lung cancer cell lines with various p53 mutations (H441, H446, and Calu1), yet this virus replicates to a high level in a lung cancer cell line with wild-type p53 (A549) and in a normal lung fibroblast line (IMR90). Viral DNA replication, expression of viral proteins, and shutoff of host cell proteins were not important variables in limiting the replication of the E1b-55kD-deleted virus. However, the cell lines resistant to host cell protein shutoff were also the most resistant to the cytopathic effect induced by mutant and wild-type virus and the only cells to survive for 8 days following infection. The E1b-55kD protein clearly has an important role in viral replication beyond its interaction with p53. Thus, an E1b-55kD-deleted virus cannot be used to specifically target viral replication to p53-mutated lung cancer cells.
Assuntos
Adenoviridae/genética , Proteínas E1B de Adenovirus/genética , Terapia Genética , Vetores Genéticos , Neoplasias Pulmonares/terapia , Adenoviridae/fisiologia , Sequência de Bases , Sobrevivência Celular , Efeito Citopatogênico Viral , Primers do DNA , Replicação do DNA/genética , Genes Virais , Humanos , Neoplasias Pulmonares/virologia , Proteína Supressora de Tumor p53/genética , Replicação Viral/genéticaRESUMO
"Most affected" (MA) and "least affected" (LA) rats, bred for extremes in motor impairment following an alcohol challenge, differed in their performance on two active avoidance tasks. In two-way shuttle avoidance, the MA line performed significantly better than the LA group, both in terms of response latencies and percent avoidances. The inferior performance of the LA line persisted across the 15 days of testing, and appeared to reflect an difference in asymptotic performance levels. In one-way avoidance, the MA line showed significantly better acquisition than the LA group; however, this difference dissipated across the 3 days of training. When tested following alcohol administration in either the one- or two-way avoidance paradigm, the MA rats showed a greater performance deficit than LA animals. These data were interpreted as indicating the generality of alcohol-related line differences to a situation motivated by aversive consequences. Moreover, the line difference in avoidance acquisition represents one of the few non-drug-related phenotypic differences that have been found in these lines. In previous generations, disparate base rates of wheel running have been reported, and the data presented here confirm and extend this finding.
Assuntos
Aprendizagem da Esquiva/efeitos dos fármacos , Etanol/farmacologia , Ratos Endogâmicos/genética , Animais , Tolerância a Medicamentos , Feminino , Masculino , Atividade Motora/efeitos dos fármacos , RatosRESUMO
MA rats, bred for greater motor impairment following subhypnotic doses of ethanol, were found to be more sensitive to the hypnotic effects of phenobarbital and chloral hydrate than were LA rats. In addition, the previously reported finding of a difference between the two lines of rats in duration of loss of righting reflex following a hypnotic dose of ethanol was replicated. The results are discussed in terms of a phenotypic difference in central nervous systems sensitivity to a range of sedative-hypnotics.
Assuntos
Hidrato de Cloral/farmacologia , Etanol/farmacologia , Genética Comportamental , Fenobarbital/farmacologia , Sono/efeitos dos fármacos , Animais , Hidrato de Cloral/administração & dosagem , Tolerância a Medicamentos , Etanol/administração & dosagem , Injeções Intraperitoneais , Masculino , Atividade Motora/efeitos dos fármacos , Fenobarbital/administração & dosagem , Fenótipo , RatosRESUMO
Offspring of mothers who consumed either 32, 19, 8, or 0% of their daily caloric intake in the form of ethanol during pregnancy were tested for passive avoidance. At 18 days of age, the number of trials to criterion and the within-group variability were direct functions of the amount of ethanol consumed by the mother during pregnancy. At 41--53 days of age, alcohol-treated pups still required more trials to criterion than controls and had faster speeds into the shock compartment on the first trial. When the progeny of mothers consuming either 35, 17, or 0% ethanol-derived calories during pregnancy were compared for conditioned taste aversion to a lithium chloride solution, a linear dose-response function was again evident. Animals in the alcohol-treated groups showed less suppression of drinking than controls. These investigations indicated that the effects of alcohol exposure in utero were manifested in behavioral outcomes involving response inhibition that were not correlated with the more familiar physical symptoms.
Assuntos
Aprendizagem da Esquiva/efeitos dos fármacos , Etanol/farmacologia , Feto/efeitos dos fármacos , Animais , Peso Corporal/efeitos dos fármacos , Dieta , Comportamento de Ingestão de Líquido/efeitos dos fármacos , Feminino , Idade Gestacional , Lítio/farmacologia , Masculino , Gravidez , Ratos , Fatores de Tempo , Privação de ÁguaRESUMO
By using a selection procedure that excluded the transforming effect of SV40, reversions to several properties of normal phenotype were for the first time obtained in a transformed Chinese hamster cell line after SV40 infection. The value of induction to recovery of contact inhibition was typical for SV40-induced reverse gene mutations. Thirteen of 15 isolated revertant clones were T-antigen positive, thus synthesizing the product of viral oncogene. Therefore, in the majority of clones reversion occurred in spite of the presence of viral transforming protein. Dot hybridization revealed the presence of SV40 DNA in all revertants including those expressing no T antigen. The virus rescued from one T-antigen positive and two negative clones proved to be infectious. Reversion to contact inhibition was followed by reversion as regards serum requirements and growth in soft agar. However, in all cases reversion was partial. Karyologic analysis of revertant clones showed that six clones maintained the hypodiploid karyotype of the parental clone, six revertants were near-tetraploid, and one was near triploid. The possible events underlying the SV40-induced reversions to normal phenotype and the role of virus-induced mutations in viral carcinogenesis are discussed.
Assuntos
Transformação Celular Neoplásica , Transformação Celular Viral , Vírus 40 dos Símios/genética , Animais , Antígenos Transformantes de Poliomavirus/análise , Linhagem Celular Transformada , Transformação Celular Neoplásica/patologia , Transformação Celular Neoplásica/ultraestrutura , Cricetinae , Cricetulus , DNA Viral/genética , Cariotipagem , Hibridização de Ácido Nucleico , Fenótipo , Vírus 40 dos Símios/imunologiaRESUMO
It was discovered in the 1970s that oncogenic viruses could induce gene mutations in mammalian cells. The phenomenon seems to be widespread: it was observed with all groups of DNA-containing viruses and some retroviruses. The mutagenic effects of the tested viruses at gene level are not locus specific. The viruses induce point mutations, including base substitutions, as well as deletions and insertions. The mutagenic effect of SV40 is controlled by the activity of the early A gene, which encodes the T antigen. Presumably, the process of integration creates the possibility for occurrence of mutations early after infection. Mutagenesis seems to be induced by an integrated virus, though to a much smaller extent. Virus-induced mutagenesis may be connected with an activation of the cell error-prone repair systems. The sum total of the experimental data shows that virus-induced mutagenesis and transformation are interrelated: (A) viruses, like other carcinogenes, display mutagenic activity; (B) viruses that are far removed from each other systematically, whose only similarity lay in being oncogenic and capable of integration, simultaneously showed the ability to induce gene mutations; (C) agents changing the rate of transformation also changed the rate of gene mutations: (D) The function of mutagenicity was mapped in the oncogene of SV40 (gene A); and the DNA of (E) mouse mammary carcinoma virus (MMTV) and avian leukosis virus (ALLV) induced tumors has been found to contain nucleotide sequences that transform 3T3NIH cells but do not carry any viral genetic information. Mutagenesis induced by oncogenic viruses may play a part in the multistage process of malignant transformation, though its contribution may be different in various specific cases and for different groups of viruses. Further studies of the uncommon mutagens, which viruses seem to be, may greatly increase our knowledge of the virus-cell relationship. An understanding of the extent of genetic danger inherent in viruses and live viral vaccines is necessary for practical medicine.
Assuntos
Transformação Celular Neoplásica , Transformação Celular Viral , Mutação , Oncogenes , Vírus 40 dos Símios/genética , Animais , Bromodesoxiuridina/farmacologia , Transformação Celular Neoplásica/efeitos dos fármacos , Células Cultivadas , Aberrações Cromossômicas , Cricetinae , Humanos , Mutação/efeitos dos fármacosRESUMO
Exposure to inescapable shock interferes with the subsequent acquisition of an appetitive operant. This deficit may be due to either associative interference or activity reduction from the inescapable shock pretreatment. The relative importance of these two factors was examined by using an appetitive response choice discrimination procedure and concurrently measuring activity. Experiment 1 demonstrated separate associative and activity effects of inescapable shock, in that the animals exposed to inescapable shock made more incorrect responses than controls and were lower in activity. Experiment 2 demonstrated that these effects resulted from the uncontrollability of the shock, not from shock exposure per se. In Experiment 3, residual effects of inescapable shock were investigated by exposing animals to discrimination reversals. On these tests, inescapably shocked animals showed performance inferior to nonshocked controls, a result indicating that the effects of inescapable shock are not completely reversed by experience with contingent reward in the discrimination task. No evidence of an activity deficit was observed during this discrimination reversal. These results strongly suggest that associative factors play a more important role than activity reduction in mediating the effects of inescapable shock, at least when these are measured in an appetitive context.
Assuntos
Aprendizagem por Associação , Desamparo Aprendido/psicologia , Aprendizagem , Motivação , Animais , Comportamento Apetitivo , Condicionamento Clássico , Condicionamento Operante , Aprendizagem por Discriminação , Eletrochoque , Reação de Fuga , Humanos , Masculino , Muridae , Inibição Proativa , Reversão de AprendizagemRESUMO
The present paper deals with effects of 12-O-tetradecanoylphorbol-13-acetate (TPA) on the frequency of induced mutations to 6-mercaptopurine (6MP) and ouabain resistance in Chinese hamster and mouse cells. UV light, bovine adenovirus 3(BAV-3) and 5-bromodeoxyuridine (BrdU) were used as mutagens. TPA was shown to raise the frequency of gene mutations induced by UV light and BAV-3 but it did not enhance the mutagenic effect of BrdU. We also examined the ability of BAV-3 and BrdU to induce tumours in mice. BrdU was shown to have no carcinogenic effect. The results suggest that TPA enhances the mutagenic effect only for carcinogenic mutagens.
Assuntos
Adenoviridae/genética , Bromodesoxiuridina/farmacologia , Transformação Celular Viral , Mercaptopurina/farmacologia , Mutagênicos , Mutação , Acetato de Tetradecanoilforbol/farmacologia , Raios Ultravioleta , Animais , Linhagem Celular , Células Cultivadas , Cricetinae , Cricetulus , CamundongosRESUMO
Induction of gene mutations by SV40 was studied in aneuploid human and Chinese hamster cells. In Chinese hamster cells SV40-induced chromosome aberrations were also studied. SV40 penetrated into the cells of both lines and induced synthesis of the T antigen. The efficiency of infection in Chinese hamster cells was tested additionally by their ability to form colonies in medium lacking the serum growth factor. The maximal number of cells with serum growth factor independence was observed on the first day after infection. When hamster cells had been maintained in "factor-free medium" for the first two passages after infection a sub-line was isolated, which synthesized T antigen 60 days after exposure to SV40. This was considered to be an indirect proof of the integration of viral genome into host chromosome. A significant increase in the frequency of chromosomal aberrations was detected in SV40-infected Chinese hamster cells. It was observed on the first and second days after treatment. The most numberous were the chromosome and chromatid breaks, which were distributed randomly in 5 morphological groups according to the chromosome length. SV40-induced mutations of resistance to 8-AG and 6-MP in human and Chinese hamster cells respectively were detected, when cells were plated in selective medium one to five days after infection. Induction was detected in all the 4 experiments with human cells and in 9 out of 11 experiments with Chinese hamster cells. Induction was highly significant according to the Wilcoxon test (P greater than 0.99), when the results of all experiments carried out in human and Chinese hamster cells were summarized. Resistance was stable after prolonged cultivation of 13 isolated clones under non-selective conditions. It is suggested that viral genome integration, gene mutations and chromosomal aberrations may have common molecular mechanisms. The role of gene mutations in virus-induced carcinogenesis is discussed.
Assuntos
Aberrações Cromossômicas , Mutação , Vírus 40 dos Símios , Aneuploidia , Antígenos Virais/análise , Azaguanina/farmacologia , Linhagem Celular , Sobrevivência Celular , Mercaptopurina/farmacologia , Replicação ViralRESUMO
The induction of chromosomal aberrations and gene mutations was studied in Chinese hamster cells after separate and combined treatment with BUdR and SV40. Separate treatment of cells with BUdR or virus infection increased the yield of chromosomal aberrations and reversions from glutamine requirement, expressed at 40 degrees C (a ts mutant), to prototrophy. The combined effect of the incorporation of BUdR into one DNA strand, and a subsequent infection by SV40 was additive as regards the percentage of aberrant metaphases. The integration of the analogue into both DNA strands followed by SV40 treatment resulted in a statistically significant increase in the frequency of aberration carrying metaphases, as compared with the frequency expected if the two agents had acted additively. The same phenomenon was detected when the frequency of reversions to glutamine independence was studied. Hence, the effect of the joint treatment by BUdR incorporated into both DNA strands and SV40 was synergistic. This is known to characterize the effect of BUdR on virus-induced transformation. Therefore, obviously the agent that enhances the malignant transformation of cells by the virus similarly modifies its mutagenic activity. The results obtained are presumed to confirm the previously advanced hypothesis that the same events following infection might control both the integration of viral DNA into the host-cell chromosome (and hence cell transformation) and virus-induced mutagenesis. The role of repair processes in the synergistic effect of BUdR and SV40 in the yield of reversions to glutamine independence is discussed.