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At least 199 records · Page 11Linked to original sources
PubMed1983

A hospital staff support program: design and evaluation.

The literature indicates that nurses on special care units experience stress resulting from the role conflict and ambiguity to which they are exposed. Role theory predicts that such individuals will become dissatisfied with their work and will decrease their confidence in supervisors and co-workers. Consequently, it was hypothesized that a staff support program designed to assist nurses to cope with role conflict and ambiguity would result in reduced stress; increased satisfaction with work, supervision, and co-workers; and decreased staff turnover. A nine week staff support program was implemented on a hospice unit in a large, private, general hospital. The program utilized an insight-oriented approach focused on specific sources of stress combined with structured exercises designed to facilitate nurses' ability to cope with stress resulting from a role conflict and ambiguity. Data were collected from two groups to hospice nurses using a Nursing Stress Scale developed for this study, the Job Description Index, and personnel records. A quasi-experimental research design was used to assess the validity and generalizability of the results of the program. Data were analyzed in four stages: (i) pre-program levels of stress and job satisfaction were analyzed using a multivariate profile analysis; (ii) correlated t-tests were used to test for significant differences between pre- and post-program levels of stress; (iii) a repeated measures ANOVA was used to examine the effect of the program on job satisfaction; (iv) turnover among the nursing staff on four other hospital units was compared to the hospice unit. Results of the evaluation indicated that the support program was effective in reducing nursing stress, increasing job satisfaction, and decreasing staff turnover. The implications of the study for the design and evaluation of hospital staff support programs are discussed.

Conflict, Psychological↗
PubMed2000

Regulation of energy intake in relation to metabolic state and nutritional status.

Inadequate energy intake can be an important contributor to weight loss in older individuals. This review highlights recent studies on possible causes of negative energy balance in older individuals. Studies of the regulation of food intake suggest that aging is associated with a significant impairment in the regulation of food intake that inhibits appropriate short-term and long-term compensation for imposed alterations in energy intake. The combination of a reduced ability to regulate energy intake, decreased sensory-specific satiety, and disadvantageous social factors such as functional limitations, social isolation and depression, increases the risk of negative energy balance leading to weight loss in older individuals.

Aged↗
PubMed1997

Intrabodies: turning the humoral immune system outside in for intracellular immunization.

Antibodies have long been used in biomedical science as in vitro tools for the identification, purification and functional manipulation of target antigens; they have been exploited in vivo for diagnostic and therapeutic applications as well. Recent advances in antibody engineering have now allowed the genes encoding antibodies to be manipulated so that the antigen binding domain can be expressed intracellularly. The specific and high-affinity binding properties of antibodies, combined with their ability to be stably expressed in precise intracellular locations inside mammalian cells, has provided a powerful new family of molecules for gene therapy applications. These intracellular antibodies are termed 'intrabodies'. Two clinical protocols have been approved by the RAC for the use of intrabodies in the treatment of an oncologic and an infectious disease. Their clinical use will in all likelihood become widespread if these initial studies show 'proof in principle'. In this article, the studies from laboratories that have used intrabodies as molecular reagents for cancer therapy and for the control of infectious diseases will be reviewed and future directions of this technology will be discussed.

Acquired Immunodeficiency Syndrome↗
PubMed2006

Acutely dysregulated, chronically disabled by the enemy within: T-cell responses to HIV-1 infection.

Human immunodeficiency virus (HIV) infection causes chronic progressive immunodeficiency and immune dysregulaton. Although simple depletion of the major target of HIV infection, the CD4+ T cell, can explain much of the immunosuppression seen, there are multiple other factors contributing to the immune dysregulation. CD4+ T-cell depletion induces a range of homeostatic mechanisms that contribute to immune activation and cell turnover, providing a milieu conducive to further viral replication and cell destruction, resulting in functional defects in various lymphoid organs. These changes are progressive and in turn compromise the homeostatic processes. Further, the infection, like any other viral infection, provokes an active immune response consisting of both CD4+ and CD8+ T-cell responses. Both appear compromised, displaying aberrant memory cell production. While some of these defects result from viral variation and the chronicity of antigen presentation, other defects of memory cell production appear very early during the primary immune response limiting the viral specific T-cell responses from the outset. This, combined with the ability of the virus to escape any successful immune responses, results in an attenuated immune response that eventually becomes exhausted, characterized by progressive deficits in T-cell repertoire. Furthermore, negative regulatory mechanisms that normally control the immune response may be aberrantly invoked, perhaps directly by the virus, further compromising the efficacy of the immune response. Rational design of effective immunotherapies depends on a clear understanding of the processes compromising the immune response to HIV.

Antigens↗
PubMed1985

A bacteriophage T7 RNA polymerase/promoter system for controlled exclusive expression of specific genes.

The RNA polymerase gene of bacteriophage T7 has been cloned into the plasmid pBR322 under the inducible control of the lambda PL promoter. After induction, T7 RNA polymerase constitutes 20% of the soluble protein of Escherichia coli, a 200-fold increase over levels found in T7-infected cells. The overproduced enzyme has been purified to homogeneity. During extraction the enzyme is sensitive to a specific proteolysis, a reaction that can be prevented by a modification of lysis conditions. The specificity of T7 RNA polymerase for its own promoters, combined with the ability to inhibit selectively the host RNA polymerase with rifampicin, permits the exclusive expression of genes under the control of a T7 RNA polymerase promoter. We describe such a coupled system and its use to express high levels of phage T7 gene 5 protein, a subunit of T7 DNA polymerase.

Bacteriophage lambda↗
PubMed1998

Stereochemistry of 2',5' nucleic acids and their constituents.

Shape and dimension of the preferred nucleotide repeats in nucleic acids are found to depend on whether the sugar-phosphate linkage is of 2',5' or 3',5' type. It is shown that a nucleotide which is "compact" in 3',5' nucleic acids is rendered "extended" and vice versa for a given sugar pucker. It is interesting that this feature is accompanied by a switch in the preferred sugar ring conformation in 3',5' and 2',5' nucleic acids. 3' ribose and 3' deoxyribose rings (in 2',5' linkages) tend to favour C2' endo and C3' endo puckers respectively in contrast to C3' endo and C2' endo puckers favored by 2' ribose and 2' deoxyribose sugars (in 3',5' linkages). The distinguishable features between the nucleotide repeats of 3',5' and 2',5' nucleic acids need to be recognised while discussing their structural properties, as well as those of a variety of complexes that could be formed involving 2',5' and 3',5' strands of DNA and RNA. Ability and stability, or lack of them, for formation of a specific combination of these complexes may be directly related to the stereochemical constraints imposed as a consequence of conformationally homogeneous or heterogeneous nature of the repeating nucleotides of the complexing chains. As a first step towards delineating stereochemical features that distinguish 2',5' nucleic acids from their naturally occurring isomer A and B type helices have been modelled using the new concept of "compact" and "extended" nucleotide repeat that seemingly unifies helix generation of both types of linkages. Helical models for 2',5' RNA with "dinucleotide" repeat based on the crystal structure of 2',5' ApU have also been obtained.

Carbohydrates↗
PubMed1978

Purification and immunologic evaluation of human melnoma-associated antigens.

Melanoma-associated antigens (MAA) were isolated and their functional immunologic properties were evaluated. Spent fetal calf serum-free culture media and 3-m KCI extracts of cultured human melanoma cells grown in this medium were used as antigen sources. Ultracentrifugal flotation on KBr was used to separate MAA and HLA antigens present in the extracts or spent culture media; thus interference by histocompatibility antigens was prevented in subsequent tests of tumor antigenic activity. MAA purified in this manner retained their immunologic functions as evidenced by their ability to produce delayed cutaneous hypersensitivity reactions in patients with melanoma, specifically combine with antimelanoma xenoantibody, and elicit production of functionally specific xenoantibody. Possible structural differences between HLA antigens and MAA were considered in evaluation of the data.

Animals↗
PubMed1995

A 48-amino-acid region of influenza A virus PB1 protein is sufficient for complex formation with PA.

The concerted activity of four influenza virus proteins, PB1, PB2, PA, and NP is necessary and sufficient for transcription and replication of the viral genome in the nucleus of the cell. The three P proteins form a heterotrimeric complex in virions and the nuclei of infected cells. Biochemical analyses have shown specific interactions between PB1 and PA as well as PB1 and PB2, indicating that PB1 is the backbone of the complex. To identify domains of PB1 involved in binding PA, a two-hybrid system adapted for mammalian cells (CV-1) was implemented. First, we demonstrate the ability of PB1 and PA to interact efficiently and specifically in reciprocal combinations of two-hybrid reporter moieties, suggesting that transcription factor module fusion did not interfere sterically or allosterically with interaction between PB1 and PA. Subsequent analyses with a set of chimeric proteins with truncations of the PB1 C termini, N termini, or internal sequences led to the identification of a region at the N terminus of PB1 responsible for binding PA. Forty-eight amino acids at the N terminus of PB1 were sufficient for binding PA in vivo with the same efficiency as the complete PB1 protein. This region of PB1 responsible for binding PA does not overlap with other previously described PB1 functional domains involved in nuclear transport and RNA polymerization. We propose to name this region of interaction with PA domain alpha, to differentiate it from other functional domains described for PB1.

Amino Acid Sequence↗
PubMed2003

Custom knock-outs with hairpin RNA-mediated gene silencing.

Hairpin (hpRNA)-mediated gene silencing exploits a cellular mechanism that recognizes double-stranded RNA (dsRNA) and subjects it and its corresponding mRNA to a sequence-specific degradation. This phenomenon is known as posttranscriptional gene silencing (PTGS) in plants and RNA interference (RNAi) in animals. dsRNA, when introduced into plant cells through hpRNA constructs, results in severe reduction of the target mRNA-the silencing effect being stably inherited over many generations. While hpRNA constructs can be made using conventional plasmids, use of generic vectors such as pHANNIBAL makes it more convenient to silence a number of genes simultaneously. Vectors, such as pHELLSGATE, that are based on the Gateway(R) technology are suitable for high-throughput gene silencing. The specificity of dsRNA silencing, it's ability to simultaneously silence multiple genes combined with the availability of high-throughput silencing vectors enables the researcher to generate custom knockout plants.

Base Sequence↗
PubMed1981

Production and characterization of a monoclonal antibody against the seed lectin of the Dolichos biflorus plant.

Spleen cells from mice immunized with the Dolichos biflorus seed lectin were fused with cells from the mouse myeloma Sp2/O-Ag14 cell line to form hybridomas. Those hybridomas producing antibodies against the seed lectin were cloned at least four times and the monoclonal antibodies from clone C11/64-56.28 were characterized and found to be specific for Subunit I of the lectin; they do not react with the structurally similar Subunit II. In previous studies, we have shown that although these two subunits appear to differ only at their COOH-terminal ends, only Subunit I has carbohydrate binding activity. Using a solid phase enzyme immunoassay, the antigenic determinant fr the monoclonal antibody was found to be located on the COOH-terminal cyanogen bromide fragment of this subunit. The monoclonal antibody inhibits the ability of the lectin to agglutinate erythrocytes and N-acetyl-D-galactosamine, the specific hapten for the lectin, inhibits the ability of the antibody to combine with the lectin. These results suggest that the monoclonal antibody recognizes a determinant that is located either at or near the active site of the lectin or that is conformationally interdependent with the active site.

Animals↗
PubMedDate not supplied

[Formation of a reaction of the hypothalamo-hypophyseal-adrenal cortex system to cooling in chick embryogenesis].

The content of glucocorticoids in the suprarenals and blood of chick embryos increased from the 12th till the 15th day of incubation. The intensive accumulation of glucocorticoids in the glands was accompanied by a relatively small increase of their concentration in blood plasma from the 15th till the 19th day. No adrenocortical reaction to cooling was registered in the 12 and 13 days old embryos. Upon cooling of 15-19 days old embryos the content of glucocorticoid hormones in the suprarenals decreased 2 to 3 times. It is suggested that the relationships between hypothalamus, hypophysis and suprarenal cortex are developed within the last week of embryogenesis. The combination of the ability for reaction with the incompletion of integration creates specific conditions for imprinting of external influences in the hypothalamic-hypophysial-suprarenal system.

Aging↗
PubMed1998

Consultation skills in radiology: a qualitative study.

OBJECTIVE: Consultation is an important part of radiologic practice. Recently, many concerns have been expressed about the lack of emphasis on consultation skills as part of the training requirements for radiologists. In order to improve the teaching and assessment of trainees, we designed a qualitative study to specify the consultation skills expected from a trainee by the end of residency. METHODS: Three successive focus groups were held with professors of radiology, residents in radiology, and referring physicians. Participants were asked to identify the various competencies required from radiologic consultants (1) spontaneously, (2) by reacting to a previously generated list, and (3) by reacting to common clinical problems encountered in radiology. RESULTS: Consultation skills thus identified were organized in a framework consisting of 2 groups: observable skills and standards of practice. Observable skills were subdivided into 5 "problem-setting" skills and 6 "results-management" skills. Seven qualities and attitudes identified were combined under the rubric "standards of practice." CONCLUSION: The specification of these abilities and competencies through a consensus process should permit the teaching of these skills and their evaluation through objective, structured clinical examinations.

Internship and Residency↗
PubMed2004

Anosognosia for plegia: specificity, extension, partiality and disunity of bodily unawareness.

This study of anosognosia for hemiplegia investigated: whether it is homogeneous; specificity to plegia of unawareness; extension to different kinds of and objects of awareness regarding plegia; partiality of unawareness. Sixty-four hemiplegic stroke patients were assessed with control subjects on (a) motor and somatosensory function, immediately followed by participants' evaluations of performance; (b) conventional structured interview questions addressing awareness of various capacities: (c) Neglect, Mental Flexibility, General Mental State, Verbal Fluency, Short-Term Memory; (d) pre- and post-performance estimates of ability on the last two; (e) estimates of current ability on bilateral and unilateral tasks, addressed by questions in 1st- and 3rd-person forms, explanations of how overestimated tasks would be accomplished, attempts at 3 bimanual tasks and post-attempt estimates of ability on these. Anosognosia for plegia was mostly associated with right-brain damage. No single factor or combination accounted for all patients. Double dissociations indicated that anosognosia can be specific to plegia: and patients do not generally overestimate other abilities. Although unawareness of paralysis and of its consequences appear linked, the latter is more widespread and persistent. Double dissociation showed that concurrent unawareness of movement failures is a separate deficit from these. There was differential awareness of different aspects of plegia. Further, some patients who overestimated current bilateral task ability when asked in 1st-person form did not overestimate when asked how well the examiner, if he was in their current condition, could do each task. This suggests split awareness of a single aspect of plegia. Patients anosognosic on conventional questioning showed two distinctions. (1) Some were unaware of movement failures when they occurred; others were aware but quickly forgot such failures and seem unable to update long-term body knowledge. (2) Some patients' explanations of bimanual task performance reflect unawareness of hemiplegia; others' explanations were bizarre and imply some awareness. The latter group's deficit appears to be nonspecific and linked to right-hemisphere predominance of anosognosia, an account of which is offered. Anosognosia for hemiplegia is not a unitary phenomenon: several factors underlie deficits in bodily awareness.

Aged↗
PubMedDate not supplied

Effects of mu- and delta-opioid-receptor antagonists on the stimulus properties of cholecystokinin.

Melton and Riley recently reported that the relatively selective mu-opioid-antagonist naloxone potentiated the stimulus properties of the gut peptide cholecystokinin (CCK). To assess whether such opioid potentiation is limited to activity at the mu-receptor subtype, in the present experiment the effects of the highly selective delta-antagonist naltrindole on CCK's stimulus properties were examined. Because in the initial report of naloxone's potentiation of CCK a relatively high, nonphysiologic dose of CCK (i.e., 13 micrograms/kg) was used as the training drug, in the current analysis subjects were trained to discriminate 5.6 micrograms/kg CCK from its vehicle and the assessments and comparisons of the effects of naloxone and naltrindole were based on this dose. Specifically, rats were administered 5.6 micrograms/kg CCK before saccharin-LiCl pairings and the CCK vehicle before saccharin alone. With such training, they rapidly acquired the drug discrimination, avoiding saccharin consumption when it was preceded by CCK and consuming the same saccharin solution when it was preceded by its vehicle. In subsequent generalization tests, doses of CCK that were ineffective in suppressing saccharin consumption (i.e., did not substitute for the training dose of CCK) did result in the suppression of saccharin consumption when combined with doses of the mu antagonist naloxone that alone had no effect on saccharin intake. On the other hand, the highly selective delta-opioid-receptor antagonist naltrindole was ineffective in potentiating the effects of CCK. Specifically, when naltrindole was combined with ineffective doses of CCK, subjects drank at control levels. The ability of naloxone to potentiate CCK's stimulus effects is consistent with a range of other demonstrations of the role of the mu-opioid-receptor subtype in CCK-opioid interactions, although the specific basis for the interaction remains unknown. Given recent findings on the effects of delta agonists and antagonists on CCK-induced activity, the failure of naltrindole to potentiate CCK's stimulus effects may be due to the absence of delta activity within this preparation, rather than the absence of delta mediation of CCK-opioid interactions in general.

Animals↗
PubMed1987

Fetal biophysical profile and perinatal death.

Antepartum assessment of 5034 high-risk pregnancies to predict perinatal death included five biophysical variables (nonstress test, fetal breathing movements, fetal movements, fetal tone, and amniotic fluid volume) which combined to form a biophysical profile score. We assessed 4148 fetuses within seven days of delivery. The ability of each variable to predict perinatal death was expressed as the likelihood ratio, which incorporates sensitivity and specificity into one number. The predictive ability was most accurate with fetal movement (likelihood ratio 48.1) and the combined biophysical profile score (likelihood ratio 51.0). The biophysical profile score was more likely to predict perinatal death due to asphyxia (seven of eight) than lethal anomaly (six of 19). The overall perinatal mortality was 7.6 per 1000 total births. The perinatal mortality rate was 1.0 for a normal biophysical profile score, 31.3 for an equivocal score, and 200.0 for an abnormal score. The false-negative rate for the biophysical profile score was 0.7 per 1000.

Amniotic Fluid↗
PubMed2000

Comparisons of the various combinations of free, complexed, and total prostate-specific antigen for the detection of prostate cancer.

OBJECTIVES: We compared the ability of three prostate-specific antigen (PSA) ratios - free-to- total PSA ratio (fPSA/tPSA), free-to-complexed PSA ratio (fPSA/cPSA), and complexed-to-total PSA ratio (cPSA/tPSA) - to distinguish prostate cancer from benign prostatic hyperplasia (BPH). METHODS: We tested 258 consecutive patients who underwent transrectal ultrasound-guided prostate needle biopsy because of an abnormal digital rectal examination or a Tandem-R PSA of >4.1 ng/ml. Free PSA (fPSA) and total PSA (tPSA) were measured by Tandem-R assay. alpha(1)-Antichymotrypsin-complexed PSA (cPSA) was measured by Markit-M PSA-ACT assay. RESULTS: Of the 258 patients, 204 had BPH, and 54 had prostate cancer. The specificity at 96% sensitivity for fPSA/tPSA, fPSA/cPSA, and cPSA/tPSA was 23, 25, and 33%, respectively. Of 162 patients with tPSA between 4.1 and 10.0 ng/ml, 132 had BPH and 30 had prostate cancer. The specificity at 96% sensitivity for f/tPSA, f/cPSA and c/tPSA was 32, 44, and 41%, respectively. There was no significant difference in the area under the receiver-operating characteristic curves among fPSA/tPSA, fPSA/cPSA, and cPSA/tPSA in the overall PSA range or in tPSA between 4.1 and 10.0 ng/ml. CONCLUSION: fPSA/tPSA, fPSA/cPSA, and cPSA/tPSA did not differ in their ability to distinguish prostate cancer from BPH.

Aged↗
PubMed2002

In vitro production and screening of DNA polymerase eta mutants for catalytic diversity.

Mutant DNA polymerases have become an increasingly important tool in biotechnology. The ability to examine the activity and specific properties of enzymes has a crucial role in the characterization of the enzyme. We have developed several systems for characterizing DNA polymerases that combine random mutagenesis with in vivo selection systems. However in vivo screening systems for specific properties are sometimes unavailable. The ability to quickly screen for polymerase activity has many applications, including the identification of compounds that can inhibit polymerase activity, identifying the properties of newly discovered polymerases, and engineering new biological properties into existing polymerases. These applications can both expand the knowledge of the basic science of polymerases and can further industrial efforts to identify new drugs that specifically target polymerase activity. Here we present a high-throughput in vitro assay to select for active polymerases. We show the applicability of this assay by measuring the level of activity for a set of in vitro synthesized polymerase mutants and by screening for the incorporation of a fluorescent nucleotide analog by DNA polymerases.

Automation↗
PubMed1995

Spontaneous acceptance of rat liver allografts is associated with an early downregulation of intragraft interleukin-4 messenger RNA expression.

Liver allografts are not rejected in the fully incompatible Lewis-RT1(1) (LEW) to blood group D Agouti-RT1a (DA) rat strain combination despite an early infiltration by recipient mononucleated cells that initially display a phenotype, an ability to respond to interleukin-2 (IL-2) and donor-specific cytotoxicity indistinguishable from that observed in the rejected, DA to LEW combination. To further analyze the mechanism of this tolerance, we have compared in these two combinations, as well as in syngeneic grafts and in normal livers, the presence of intrahepatic cytokine transcripts (IL-1 alpha, IL-2, IL-4, IL-6, IL-10, tumor necrosis factor [TNF]-alpha, TNF-beta, and transforming growth factor [TGF]-beta) by a semiquantitative polymerase chain reaction (PCR) or by northern-blotting. In normal livers or syngeneic grafts, IL-1 alpha, TNF-beta, and TGF-beta were the only cytokines detected by these methods. The levels of all cytokine transcripts were increased in allogeneic grafts. Expression of cytokine transcripts was very similar in the two allogeneic strain combinations except IL-4, which was expressed at a much lower level in the nonrejected strain than in the rejected strain from day 2 onward. We conclude that selective downregulation of IL-4 gene expression is associated with, and a potential mediator of, the induction of tolerance in this model.

Acute-Phase Reaction↗