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The COVID-19 outbreak has rapidly progressed into a worldwide pandemic, and the need for social distancing has changed the way we learn and work. Our monthly OMFS journal club has been no different, and is currently meeting on the video conferencing application Microsoft Teams. The use of a virtual setting for training in medicine and dentistry is not new and, as in the case of our recent move to a virtual medium, it may be that COVID-19 has fast-tracked this digital transformation. There are of course disadvantages to online teaching that traditional face-to-face teaching overcomes. We conducted a survey to examine how trainees' attitudes and experiences have altered with this change, and to understand whether some elements of this new style of training may be advantageous in the post-pandemic world. We aimed to assess trainees' attitudes towards online teaching, and which elements, if any, would be beneficial once face-to-face teaching becomes possible again. A survey was created for all trainees taking part in journal club meetings at Bradford Teaching Hospitals. Multiple-choice and Likert scale questions were designed to ascertain the differences in experience between online and face-to-face settings. A Wilcoxon matched pairs signed test was used to analyse the results. Responses were kept anonymous. Results showed that the majority of trainees found it easier to attend the online journal club, and also indicated that the most found Microsoft Teams easy to use, though we did not have another online application for comparison. There was no significant difference in participation comfort between the two settings, though trainees felt that the online setting considerably improved learning effectiveness. Furthermore, 79% (11/14) thought that online tutorials and meetings should replace traditional face-to-face meetings in the future. The use of internet technology such as video conferencing is not new, and although journal clubs are typically held in academic institutions, online and virtual clubs are flourishing. With an array of advantages, there is no shying away from the trend to move our teaching to a virtual medium. COVID-19 may have just provided the stimulus that has forced this transformation to accelerate.
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COVID-19 , Humanos , Aprendizaje , Pandemias , SARS-CoV-2 , TecnologíaRESUMEN
Transfer of genetic information can be effected by incubation of cultured eucaryotic cells with isolated metaphase chromosomes. In most cases, a resulting transformed cell contains only a fragment of a donor chromosome. The amount of transferred donor DNA has been quantified in 11 independent mouse A9 transformants by nucleic acid hybridization analysis. Each transformant had been selected for hprt (hypoxanthine phosphoribosyltransferase; EC 2.4.2.8) transfer and contained part of the human X chromosome. A labeled probe of transcribed human X-chromosomal DNA was prepared by hybridization of nick-translated unique-sequence human DNA with whole cellular RNA from a human-mouse hybrid cell line, A9/HRBC2-A, containing a single human chromosome., X. The amount of human X-chromosomal DNA in the transformants was quantitated by comparing the hybridization of this probe with transformant and A9/HRBC2-A DNAs. Two unstable transformants which had a microscopically detectable donor chromosome fragment contained 15% of the human X-chromosomal single-copy DNA. Four other unstable transformants contained 4 to 7% of human X-chromosomal DNA sequences. The transferred DNA was below the level of detection in three other unstable and in all three stable transformants. We conclude that the initial transfer event can introduce a substantial amount of genetic information but only smaller amounts of DNA are stably incorporated by integration.
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Cromosomas Sexuales , Transformación Genética , Cromosoma X , Animales , Secuencia de Bases , ADN/análisis , Femenino , Células HeLa , Humanos , Células Híbridas , Células L , Ratones , Hibridación de Ácido Nucleico , ARN/análisis , Transcripción GenéticaRESUMEN
Human cytomegalovirus and herpes simplex virus DNA probes were labeled in vitro and hybridized to the DNA extracted from brains of patients with multiple sclerosis (MS) to detect the presence of genetic information related to these viruses. We were unable to detect any virus-related genetic information complementary to these probes. These results indicate that the two viruses are not involved in MS, or else the genetic information, if present, is below the sensitivity of detection of this hybridization technique.
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Infecciones por Citomegalovirus/microbiología , Citomegalovirus/genética , Herpes Simple/microbiología , Esclerosis Múltiple/microbiología , Simplexvirus/genética , Adulto , Anciano , Encéfalo/microbiología , ADN Viral/genética , Femenino , Humanos , Hibridación Genética , Masculino , Persona de Mediana EdadRESUMEN
L-forms from a Corynebacterium were induced in hyperosmolar media and gradually adapted to normal osmolarity over a period of two years. During this adaptation several morphologic L-form variants derived from the L-form cultures and were serologically identified as Acholeplasma laidlawii A. The possibility that the bacterial and L-form cultures were contaminated with acholeplasmas was carefully investigated; this was determined not to be the case. Membrane protein gel electrophoresis patterns of these L-form variants were identical to the ATCC A. laidlawii strain PG-8. Acholeplasma phage MVL-1 displayed no affinity for these L-form variants. Phage MVL-2 showed low affinity, but after virus enhancement in the specific host, high plaquing efficiency ensued. DNA hybridization experiments showed a high level of nucleotide sequence homology (greater than 90%) between the L-form-derived variants and PG-8. The homology between the diphtheroid L-forms and the PG-8 strain was 16.4% with te50 values of 86%; this indicates strong base pairing homology. These findings suggest that the L-form variants are acholeplasmas and that they are biologically and genetically related to the Corynebacterium L-forms.
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Acholeplasma laidlawii/fisiología , Corynebacterium/citología , Formas L/fisiología , Acholeplasma laidlawii/clasificación , Acholeplasma laidlawii/citología , Acholeplasma laidlawii/genética , Proteínas Bacterianas/análisis , Bacteriófagos , Composición de Base , Secuencia de Bases , Corynebacterium/crecimiento & desarrollo , ADN Bacteriano/análisis , Humanos , Formas L/clasificación , Formas L/genética , Proteínas de la Membrana/análisis , Hibridación de Ácido Nucleico , Concentración Osmolar , Pruebas Serológicas , Cloruro de Sodio/farmacologíaRESUMEN
We report here the development of a fatal lymphoproliferative disease in a common marmoset (Callithrix jacchus) following inoculation of the Ag876 strain of Epstein-Barr virus (EBV) and of the tumor promoting agent 12-O-tetradecanoylphorbol-13-acetate (TPA). The marmoset showed antibodies against EBV capsid and early antigens (VCA, EA) but not against nuclear antigen (EBNA). EBNA was detected in impression smears from lymph nodes and liver, and the presence of the EBV genome was detected from the same organs by hydridization techniques. To our knowledge this is the first report of the oncogenicity of this strain of EBV. The need for further studies to assess the in vivo interaction between EBV and tumor promoting agents in the development of malignancies is stressed.
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Trastornos Linfoproliferativos/etiología , Infecciones Tumorales por Virus/etiología , Animales , Anticuerpos Antivirales , Callithrix , Femenino , Herpesvirus Humano 4/inmunología , Trastornos Linfoproliferativos/inmunología , Trastornos Linfoproliferativos/patología , Acetato de Tetradecanoilforbol/toxicidad , Infecciones Tumorales por Virus/inmunología , Infecciones Tumorales por Virus/patologíaRESUMEN
The present article, continuation of a previous work, is an attempt to study the plants to which magical properties are attributed. It is based on published information as well as survey conducted by the authors.
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In this article, superstitions prevailing in India. attached to medicinal plants have been compiled. The author opines that there must be some rationale behind each of these superstitious practices which merits painstaking study to understand thm in the proper perspective.
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A [3H[cDNA probe synthesized from the RNA genome of Rauscher murine leukemia virus (MuLVR) and purified by hybridization to MuLVR70S RNA was hybridized to DNA from human normal and hemotopoietic neoplasia tissues. This cDNA hybridized completely to its homologous 70S RNA and was free of self-complementary sequences. Sequences complementary to MuLVR cDNA were found in DNA from tissues of some patients with leukemia (2 of 8), Hodgkin's disease (3 of 10), and one patient with multiple myeloma. DNA from spleen and kidney of a patient with nonneoplastic disease did not contain detectable MuLVR-related sequences. These virus-related sequences in the DNA from these neoplastic tissues were related but not identical to MuLVR sequences because differences of approximately 6 degrees in the midpoints of thermal elution profiles were found between the heterologous and homologous duplexes. These nucleotide sequences are not the same as the proviral sequences of baboon type-C virus previously found from some other patients with leukemia [Reitz et al. (1976) Proc. Natl. Acad. Sci. USA 73,2113-2117; Wong-Staal et al. (1976) Nature 262, 190-195], because there is no sequence homology between nucleic acids from MuLVR and baboon virus. The absence of these nucleic acid sequences in many tissues of patients with neoplasia and from the few tissues examined from people with nonneoplastic disease suggests that they are not endogenous elements but are acquired after fertilization. Taken together with the previous detection of baboon and woolly monkey type-C viral related components in some human tumors, the results suggest acquisition of at least three types of type-C viral sequences in the human population.
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ADN de Neoplasias/análisis , ADN Viral/análisis , Enfermedad de Hodgkin/análisis , Leucemia Mieloide Aguda/análisis , Mieloma Múltiple/análisis , Virus Rauscher/análisis , Retroviridae/análisis , Bazo/análisis , Secuencia de Bases , Linfoma de Burkitt/análisis , ADN/análisis , Humanos , Leucemia Mieloide/análisis , Hibridación de Ácido NucleicoRESUMEN
Pharmacognosy, Pharmacology, Clinical studies and photochemistry of the four plants, viz., Convolvulus pluricaulis, Evolvulus alsinoides, Canscora decussate and Clitoria ternatea commonly used as the drug Shankapushphi have been reviewed here.
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Highly purified DNAs from three homothallic species Neurospora africana, N. dodgei and N. lineolata; three reference strains representing authentic heterothallic species, N. crassa, N. intermedia and N. sitophila; and two strains of pseudo-homothallic species N. tetrasperma were characterized by spectrophotometry and DNA reassociation using hydroxyapatite chromatography. All of these known species are closely related on the basis of DNA characteristics such as base composition and thermal denaturation profiles of major DNA components. Minor components of ascospore DNA was, however, only 5-7% of total DNA instead of 15-20% minor component DNA shown by mycelial DNA. Species belonging to same group were not distinguishable morphologically, but all of these species were distinguishable by DNA:DNA homology studies. Greater DNA homology was noticed between DNAs of heterothallic species and DNAs of pseudohomothallic species than DNA of true homothallic species. Difference on DNA-nucleotide sequences among homothallic species was very little. Pseudo-homothallic species N. tetrasperma was found to be distinctly different from homothallic species but closer to heterothallic species based on such studies.
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ADN , Neurospora crassa , Neurospora , Especificidad de la Especie , Secuencia de Bases , Hibridación de Ácido Nucleico , FilogeniaRESUMEN
Single-stranded 3H-DNA probes complementary to the RNA of Rauscher murine leukemia virus and of simian sarcoma virus were prepared using techniques that permitted complete transcription of the viral genome of each virus. These probes were used in DNA-DNA hybridization studies with the cellular DNA from uncultured specimens of spleens and placentas of patients with systemic lupus erythematosus (SLE). No proviral DNA sequences related to these viruses were detected in these tissues. The results presented here do not support previously reported antigenic data implicating type-C oncornavirus infection of these organs in SLE.
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ADN Viral , Lupus Eritematoso Sistémico/microbiología , Placenta/microbiología , Retroviridae , Bazo/microbiología , ADN Viral/análisis , Femenino , Humanos , Hibridación de Ácido Nucleico , Placenta/ultraestructura , Embarazo , Retroviridae/genética , Retroviridae/aislamiento & purificación , Bazo/ultraestructuraRESUMEN
3H-labeled Acholeplasma DNA probes were generated in vitro by the nick-translation method and used to determine the nucleotide sequence homology among the type strains of the eight currently recognized species of Acholeplasma. Very little nucleotide sequence homology (less than or equal to 18%) was found among the eight species, with heteroduplexes showing at least 12% or more mismatching as determined by thermal elution midpoints. The small amount of nucleotide sequence homology among the eight species indicates that these species are quite distinct and are not closely related to each other genomically.
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Acholeplasma/genética , ADN Bacteriano/análisis , Secuencia de Bases , Hibridación de Ácido Nucleico , Especificidad de la EspecieRESUMEN
Latent murine cytomegalovirus (MCMV) infection of BALB/c mouse spleens was studied using several methods including an explant tissue culture technique, co-cultivation on allogeneic and syngeneic cell cultures and nucleic acid hybridization. BALB/c mice experience latent infection which persists for at least 6 months and involves only a small fraction of spleen cells. The explant culture technique proved to be much more sensitive than other methods for detecting latent infection of lymphoid tissues.
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Infecciones por Citomegalovirus/microbiología , Citomegalovirus/crecimiento & desarrollo , Bazo/microbiología , Animales , Células Cultivadas , Técnicas de Cultivo , ADN Viral/análisis , Ratones , Ratones Endogámicos BALB C , Hibridación de Ácido Nucleico , Factores de TiempoRESUMEN
Lymphoblastoid cell lines were derived from patients with active systemic lupus erythematosus by allowing spontaneous transformation of peripheral B lymphocytes (B cells) harboring endogenous Epstein-Barr virus or by superinfecting peripheral lymphocytes with exogeneous Epstein-Barr virus. Results of extensive studies aimed at identifying type C oncornaviruses in these lymphoblastoid cells were entirely negative by electron microscopy, DNA-DNA hybridization, reverse transcriptase assays, and cocultivation experiments. These results do not support the postulated association of oncornavirus infection in human systemic erythematosus.
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Herpesvirus Humano 4/aislamiento & purificación , Lupus Eritematoso Sistémico/microbiología , Retroviridae/aislamiento & purificación , Linfocitos B , Bromodesoxiuridina , Línea Celular , Humanos , Activación de Linfocitos , Linfocitos/ultraestructura , Hibridación de Ácido Nucleico , ADN Polimerasa Dirigida por ARNRESUMEN
Radiolabeled DNA probes prepared in vitro by the nick translation method were used to determine the nucleotide sequence homology among the eight established and one unclassified species of Acholeplasma. Very little DNA homology (2 to 21 percent) was found among these nine distinct species and the heteroduplexes showed at least 15 percent mismatching as determined by thermal elution endpoints. The data obtained by hybridization analyses paralleled the results obtained by the growth inhibition and epi-immunofluorescence serologic procedures. The small amount of nucleotide sequence homology among the nine distinct species indicate that the Acholeplasma species are quite distinct and unrelated to each other genomically, findings which should provide useful insight on the molecular biology and evolutionary pathways of these organisms. Labeled 3H-DNA probes to five strains of either A. laidlawii or A. axanthum hybridized to a varying degree to excess amounts of unlabeled DNAs from 12 strains of A. laidlawii and six strains of A. axanthum, respectively. Nucleic acid hybridization analyses showed a wide variation (48 to 100 percent) in DNA homologies among different strains of the two species. The results demonstrate that strains of A. laidlawii and/or A. axanthum isolated from diverse hosts and habitats (birds, rodents, cats, swine, sheep, cattle, horses, goats, primates, and plants) exhibit extensive genotypic variations. 3H-DNA-DNA hybridization procedures were found to be extremely useful in establishing or confirming the existence of distinct species within the genus Acholeplasma.
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Acholeplasma/genética , ADN Bacteriano/genética , Hibridación de Ácido Nucleico , Acholeplasma laidlawii/genética , Animales , Secuencia de Bases , ADN Bacteriano/aislamiento & purificación , Genes Bacterianos , Humanos , Mycoplasma/genética , Mycoplasma pneumoniae/genética , Especificidad de la EspecieRESUMEN
This study compares the intraspecies genetic relatedness among strains of two established species of Acholeplasma. Radiolabelled DNA probes were prepared from three strains of Acholeplasma laidlawii and two strains of Acholeplasma axanthum, by using the nick translation method. The labelled DNA probes of these two strains were hybridized to an excess of unlabelled DNA from 12 strains of Acholeplasma laidlawii and from six strains of Acholeplasma axanthum, respectively. Nucleic acid hybridization analyses showed a wide variation among strains within each of the two established species, ranging from 48 to 100% homology. The results demonstrate that strains isolated from diverse hosts and habitats within a given species of Acholeplasma exhibit extensive genotypic variations.