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Biomedical subjects

A L Boyd

Publications and source records attributed to A L Boyd.

At least 19 recordsLinked to original sources
PubMed2000

Anagogy of autonomy.

The philosophical and ethical concept of autonomy is herein examined, ex post facto, using an existential lens to examine the process of a personal friend's dying. Anagogy, defined as interpretation of a word, passage, or text that finds beyond the literal, allegorical, and moral senses a fourth and ultimate spiritual or mystical sense, is intended to enlarge the understanding of the use of autonomy in this case. The idea of personhood linked inextricably to reason is, therefore, understood as empowering an individual to choose among various actions, to define and redefine life goals, and to give priority to selected values and moral tenants, which reveal a moral hermeneutic. Conditions and circumstances, existentially exposed, limit choice in unexpected ways, such that the predicted value of autonomy is vulnerable to misuse or misunderstanding. The intent to respect the dignity of every person is central to the philosophy of Respect for Persons ethics, and assumes that autonomy, as freedom of the moral agent, is a moral duty. Implicit reality of freedom is, in a practical sense, essential to being rational agents who can thereby exercise informed choice. The moral law, law of freedom, involves the autonomy of the will and an ultimate end to which all action is directed. Defined as the highest good, morality unites virtue and happiness by ascribing the ultimate end sought as God. The freedom to use rational will finds principles within its own rational nature. The ability to create maxims is autonomy of the will, which equates with the dignity of persons. My recent experience as a companion to a personal friend with a terminal illness inspired me to re-evaluate the concept of autonomy as it is too often interpreted in modern ethical discourse as a individualistic right of choice as opposed to the hermeneutic of dignity of person. This paper describes a shift of position in understanding the paradox of autonomy in this existential context.

Advance Directives↗
PubMed1999

Fiberoptic bronchoscopic placement of self-expandable metallic airway stents for the treatment of tracheobronchial obstruction and fistulas.

Tracheobronchial stent use has been reported in the medical literature for more than 40 years. Silicone stents are the most widely used stents in therapy for varying tracheobronchial lesions at most centers. However, newer designs and modifications of stents are now available with delivery systems that have been designed to facilitate using fiberoptic bronchoscopy. We describe our initial experience placing 13 self-expandable metallic Wallstent stents, including the covered design, in a total of seven patients via a fiberoptic bronchoscope. All patients had benign or malignant obstructing lesions and one patient had an associated malignant tracheoesophageal fistula. The procedure was technically easy and was well tolerated. Following stenting there was a visible increase in airway diameter and a marked improvement in symptoms for all patients. Median survival after stent placement is currently 10 months.

Adult↗
PubMed1997

Introducing case management to a general medicine ward team of a teaching hospital.

PURPOSE: To introduce case management to a general medicine ward team of a teaching hospital to improve patient care and ensure comprehensive longitudinal care. METHOD: The Department of Veterans Affairs Medical Center is one of four hospitals used by University of Oklahoma School of Medicine residents. There are five medicine teams, each comprising a second- or third-year resident, one or two interns, two medical students, and a faculty physician. The case-management program was initiated in November 1994. No attempt was made to limit the residents assigned to the case-managed team (i.e., many residents who worked with the case-managed team subsequently rotated through the other teams). Patients were assigned to the teams by rotation, and no attempt was made to adjust for the severity of illness among admissions. The teams were separated as follows: pre-case-management teams (all five teams prior to the case-management program), non-case-management teams (the four teams without case managers after the program's initiation), and the case-management team. The study periods were January-July 1994 (pre-case management) and January-July 1995 (after case management). RESULTS: The numbers of patients treated by the three groups were 1,305, 1,139, and 289, respectively. The median length of stay for pre-case-management patients was 5 days (interquartile range, 3-9 days); for non-case-management patients, 5 days (range, 3-8 days); and for case-management patients, 5 days (range, 3-7 days). The cumulative distribution of lengths of stay for case-management patients was significantly different from those of the other study groups by the Kolmogorov-Smirnov test (p = .02). More case-management patients were discharged by day 7. Rates of readmission were not significantly different between the teams. CONCLUSION: In this study a case-management program was effectively implemented in a teaching hospital, resulting in reduced lengths of stay for patients. As academic health centers become more concerned with efficiency and cost, case management should be seriously considered as a way to deal with such issues.

Academic Medical Centers↗
PubMed1995

An assessment of the antisense properties of RNase H-competent and steric-blocking oligomers.

The antisense activity and gene specificity of two classes of oligonucleotides (ONs) were directly compared in a highly controlled assay. One class of ONs has been proposed to act by targeting the degradation of specific RNAs through an RNase H-mediated mechanism and consists of C-5 propynyl pyrimidine phosphorothioate ONs (propyne-S-ON). The second class of antisense agents has been proposed to function by sterically blocking target RNA formation, transport or translation and includes sugar modified (2'-O-allyl) ONs and peptide nucleic acids (PNAs). Using a CV-1 cell based microinjection assay, we targeted antisense agents representing both classes to various cloned sequences localized within the SV40 large T antigen RNA. We determined the propyne-S-ON was the most potent and gene-specific agent of the two classes which likely reflected its ability to allow RNase H cleavage of its target. The PNA oligomer inhibited T Ag expression via an antisense mechanism, but was less effective than the propyne-S-ON; the lack of potency may have been due in part to the PNAs slow kinetics of RNA association. Interestingly, unlike the 2'-O-allyl ON, the antisense activity of the PNA was not restricted to the 5' untranslated region of the T Ag RNA. Based on these findings we conclude that PNAs could be effective antisense agents with additional chemical modification that will lead to more rapid association with their RNA target.

Allosteric Site↗
PubMed1993

Pathogenicity of molecularly cloned bovine leukemia virus.

To delineate the mechanisms of bovine leukemia virus (BLV) pathogenesis, four full-length BLV clones, 1, 8, 9, and 13, derived from the transformed cell line FLK-BLV and a clone construct, pBLV913, were introduced into bovine spleen cells by microinjection. Microinjected cells exhibited cytopathic effects and produced BLV p24 and gp51 antigens and infectious virus. The construct, pBLV913, was selected for infection of two sheep by inoculation of microinjected cells. After 15 months, peripheral blood mononuclear cells from these sheep served as inocula for the transfer of infection to four additional sheep. All six infected sheep seroconverted to BLV and had detectable BLV DNA in peripheral blood mononuclear cells after amplification by polymerase chain reaction. Four of the six sheep developed altered B/T-lymphocyte ratios between 33 and 53 months postinfection. One sheep died of unrelated causes, and one remained hematologically normal. Two of the affected sheep developed B lymphocytosis comparable to that observed in animals inoculated with peripheral blood mononuclear cells from BLV-infected cattle. This expanded B-lymphocyte population was characterized by elevated expression of B-cell surface markers, spontaneous blastogenesis, virus expression in vitro, and increased, polyclonally integrated provirus. One of these two sheep developed lymphocytic leukemia-lymphoma at 57 months postinfection. Leukemic cells had the same phenotype and harbored a single, monoclonally integrated provirus but produced no virus after in vitro cultivation. The range in clinical response to in vivo infection with cloned BLV suggests an important role for host immune response in the progression of virus replication and pathogenesis.

Animals↗
PubMed1993

Review: molecular biology of transgenic animals.

The amazing pace of discovery within the field of molecular biology has expanded the understanding of as well as the potential for genetic engineering in laboratory and domestic animals. Recently, specific techniques have been perfected, including recombinant DNA, genetic cloning, analysis of gene expression, and the sequencing of nucleic acids and proteins. These molecular techniques combined with methods allowing transfer of the recombinant genes into living cells and fertilized eggs advent the production of transgenic mice and other animals, the application of which is unlimited.

Animals↗
PubMed1992

Cooperativity of SV40 T antigen and ras in progressive stages of transformation of human fibroblasts.

Human diploid fibroblasts immortalized by SV40 T antigen provide an experimental system for studying the progression and synergism in transformation by secondary oncogenes. We have utilized the human fibroblast line HAL, which was immortalized with an orgin-defective SV40 genome encoding a temperature-sensitive T antigen, to study the cooperativity between SV40 T antigen and the ras oncogene in the progression of transformation. This study demonstrates that HAL cells possess characteristic growth patterns, requiring 10% serum, are anchorage dependent, and express a temperature-sensitive T antigen. HAL cells rely on the normal functioning of T antigen for continual growth and therefore do not proliferate at 39 degrees C. Three new derivatives of the HAL cell line were generated by microinjection of the ras oncogene. The cell line v-ras-HAL was derived by microinjection of HAL cells with v-Ha-ras DNA. The cell lines c-rasSVneo-HAL and c-rasLTRhygro-HAL were established by microinjection of HAL cells with the plasmids pSV2neoT24 or fpHVT24, respectively, wherein the ras gene is transcriptionally regulated by the cellular promoter and driven by either the SV40 enhancer or an upstream LTR enhancer. The three ras containing cell lines grow in reduced serum concentrations (0 to 5%), are anchorage independent, and express both T antigen and ras p21. The v-ras-HAL and c-rasSVneo-HAL cell lines are still dependent upon the normal functioning of T antigen for continual growth at 39 degrees C, however the c-rasLTRhygro-HAL cell line does proliferate at 39 degrees C in 10% serum-containing medium. Therefore, we propose that neither v-Ha-ras nor c-ras can replace T antigen at 39 degrees C; rather T antigen and ras cooperate in progressive stages of transformation of human fibroblasts.

Antigens, Polyomavirus Transforming↗
PubMed1991

Isolation of bovine leukemia virus infected endothelial cells from cattle with persistent lymphocytosis.

Incubation of adherent cells derived from peripheral blood mononuclear cells of cattle naturally infected with bovine leukemia virus (BLV) led to the establishment of three, persistently infected, primary cell cultures. These cultures were obtained exclusively from animals exhibiting persistent lymphocytosis, and not from uninfected or infected, hematologically normal cattle. The cells contained monoclonally integrated, full length BLV provirus, indicating that each culture resulted from clonal expansion of a single cell. They expressed high levels of all BLV specific mRNAs and showed intracellular reactivity to antibodies directed to viral gag and env proteins. Viral particle morphogenesis was highly restricted as determined by low levels of reverse transcriptase activity in cell supernatants and the paucity of viral particles on the cell surface. Analysis of cellular antigenic determinants, using monoclonal antibodies to bovine leukocyte differentiation and major histocompatibility complex antigens, was inconclusive. Cytochemical, morphologic, and ultrastructural analyses were consistent with endothelial cells and they exhibited the distinctive functional capacity of endothelial cells derived from specialized postcapillary venules, which constitute sites of lymphocyte extravasation. These data suggest that infection of these endothelial cells may be involved in the development of persistent lymphocytosis in BLV-infected animals.

Animals↗
PubMed1988

Microinjection and expression of an infectious proviral clone and subgenomic envelope construct of a human immunodeficiency virus.

An infectious proviral clone of the human immunodeficiency virus (HIV) was microinjected into the cell nucleus in six cell lines derived from caprine, ovine, bovine, or human solid tissue to study the utility of this method in effecting viral gene expression in nonlymphoid cells. Immunofluorescence assays for HIV demonstrated viral gene expression in only 5% of cells (100-200 cells per line) 24-48 h after microinjection; however, no reverse transcriptase activity was detectable, presumably due to a low level of virus release in this limited number of cells. Therefore, to indirectly assess infectious virus release, microinjected cells were cocultured with human T4 antigen-positive lymphocytes (H9) sensitive to HIV infection. Syncytia formation, electron microscopy, reverse transcriptase activity, and radioimmunoassay for HIV p24 were used to monitor viral gene expression in cocultures. HIV was efficiently recovered by cocultivating H9 with microinjected cells 48 h after microinjection, regardless of the tissue type or species of origin. H9 syncytia were visualized in some cocultures as early as day 5 but were readily apparent in all experiments on days 7-10. Syncytia induction in H9 was the earliest and most reliable indicator of infectious virus release. A recombinant construct containing a subgenomic envelope gene derived from the proviral clone of HIV was microinjected into human glioblastoma cells. Twenty-four to 48 h after manipulation, 5-20% of microinjected cells were found by immunofluorescence assay to express low levels of a putative gp120. These results suggest a possible approach to producing virus-free HIV envelope antigens in mammalian cells and may be relevant to subunit vaccine development.

Acquired Immunodeficiency Syndrome↗
PubMed1988

Molecular cloning of biologically active proviruses of bovine immunodeficiency-like virus.

A series of independent proviral molecular clones of bovine immunodeficiency-like virus (BIV) obtained from a genomic library of BIV-infected bovine cell DNA were physically and biologically characterized. Heteroduplex mapping shows that two of these BIV clones (106 and 127) contain uninterrupted proviral sequences approximately 9.0 kb in length, flanked by nonhomologous bovine cellular sequences. Microinjection of purified DNA from BIV clone 106 or 127 into susceptible bovine cells produces virus-specific cytopathic effects, including syncytium induction, supernatant reverse transcriptase activity, and infectious virus particle formation, similar to the effects produced by parental virus stock. Using restriction enzyme mapping, it was determined that the two infectious clones share 13 of 14 sites mapped within the provirus; thus, based on this criterion, the two clones are nearly identical, with the exception of a single polymorphic site recognized in the 3' half of the genome. BIV appears to be an exogenous pathogenic virus, because Southern hybridization analyses detected no endogenous sequences related to BIV in DNA from a variety of uninfected bovine cells and tissues. Most of the BIV-related DNA found in cells 96 hr after infection is present as linear unintegrated viral DNA, although the presence of host flanking sequences in our proviral clones indicates that integration takes place. These biologically active clones of BIV will be of use in defining further the mechanisms of BIV pathogenesis and in engineering specific diagnostic reagents to determine the prevalence of BIV in cattle populations.

Animals↗
PubMed1988

Isolation of multiple antibiotic resistant Enterobacteriaceae from river water.

Water samples from the Monocacy River in Frederick County, Maryland, yielded twenty-four isolates which were resistant to tetracycline (TeR, 25 micrograms/ml). Although these organisms were not initially cultured on a coliform-selective medium, twenty-two of the isolates were Gram-negative and carriers of antibiotic resistance to five or more antibiotics; erythromycin, methicillin, novobiocin, penicillin and tetracycline. Of the isolates 45% were biochemically identified as Providencia stuartii; one isolate which contained a 29.4 kilobase plasmid carried the determinant for tetracycline resistance.

Ampicillin Resistance↗
PubMed1986

Strain and sex differences in susceptibility of rats to dioctyltin dichloride.

Treatment with dioctyltin dichloride (DOTC) induced increased mortality, atrophy of the thymus and suppression of responses to concanavalin A. Brown Norway (BN) rats were more susceptible than Lewis (LEW) to the lethal effects of DOTC and males were more susceptible than females. Increased mortality did not correlate with changes in the histological appearance of the thymus. LEW X BN F1 hybrids resembled the LEW parent in susceptibility to the lethal effects of DOTC and the BN parent in susceptibility to changes in the thymus.

Animals↗
PubMed1981

Herpes simplex virus (type 1) thymidine kinase gene does not transform cells morphologically.

BALB/c-derived 10E2 cells were made thymidine kinase(TK)-negative and one isolated clone (B2) was used for studying morphological and biochemical transformations by herpes simplex virus (HSV) type 1 (strain 10412). The B2 cells displayed a "normal" flat appearance and were nontumorigenic in nude mice when tested at frequent intervals over a period of 45 subcultures. B2 cells infected with UV-irradiated HSV (UV-HSV) and maintained in normal growth medium showed foci of spindle-shaped cells after one subculture. The cells from these morphologically transformed foci were tumorigenic in nude mice and were TK negative. B2 cells infected with UV-HSV or transfected with the HSV-1 TK gene and maintained in TK-selective medium showed discrete colonies of cells which displayed a normal flat appearance and expressed the viral TK enzyme. These biochemically transformed B2 cells were nontumorigenic in nude mice. The findings with B2 cells indicate that biochemical and morphological transformations by HSV-1 are independent events and suggest that the HSV-1 TK gene is a suitable vehicle for introducing non-TK genes into cells to assess their transforming potential.

Animals↗
PubMed1978

Activation of endogenous type C virus in BALB/c mouse cells by herpesvirus DNA.

Several virion and nonvirion DNAs were tested for the ability to activate endogenous type C virus in BALB/c-derived mouse cells using the calcium precipitation technique. The DNAs from all herpesviruses tested activated xenotropic type C virus synthesis. These included DNAs from herpes simplex virus types 1 and 2, Epstein-Barr virus, human cytomegalovirus, SA8 virus, infectious bovine rhinotracheitis virus, pseudorabies virus, and herpes saimiri virus (M-DNA). In contrast, DNAs from vaccinia virus, simian virus 40, primate cells, bacteria, mycoplasma, and salmon sperm showed no ability to activate type C virus when tested under the same conditions. Several herpesviruses and vaccinia virus, which were highly infectious for the BALB/c cells used, were tested for their ability to activate type C virus after UV irradiation. All herpesviruses tested were positive, while vaccinia virus was negative. Unirradiated simian virus 40 also showed no ability to activate type C virus. Activation of type C virus by DNA from herpes simplex virus was observed after shearing or sonication of the DNA to an average size of 3 x 10(6) daltons, but was not observed with DNA sonicated to an average size of 1 x 10(6) daltons. Alkali denaturation of DNA from herpes simplex virus or treatment with DNase, but not RNase, destroyed its ability to activate type C virus, as did crosslinking of the DNA with 4,5',8-trimethylpsoralen (psoralen) and light.

Cell Line↗
PubMed1976

Cross-reacting herpes simplex virus antigens in hamster and mouse cells transformed by ultraviolet light-inactivated herpes simplex virus type 2.

Murine and hamster cell lines, each transformed with a different strain of herpes simplex virus (HSV), were examined for cross-reacting antigens by in vitro and in vivo assays. A comparative study by the indirect immunofluorescence technique detected common cross-reacting viral antigens. Cytoplasmic fluorescence patterns were observed in the 333-8-9 hamster line, the H238 murine line, and the H238 clonal lines; these patterns were identical to the fluorescence pattern of HSV -2-infected controls when reacted with HSV antiserum. Tumor rejection studies in the BALB/c host indicated that each cell line provided immunity against a tumorigenic challenge of transformed mouse cells. The H238 clone EC1 3 provided a 53% immunity against itself at an inoculum of 10(6); the 333-8-9 line supported a 26% immunity. These data demonstrate a common HSV antigenicity between the murine and hamster transformed lines and further indicate that the HSV genome is involved in transformation.

Animals↗