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Biomedical subjects

J Saunders

Publications and source records attributed to J Saunders.

At least 55 records · Page 3Linked to original sources
PubMed1998

Relevant radiological anatomy of the pig as a training model in interventional radiology.

The use of swine for teaching purposes in medicine and surgery has largely increased in recent years. Detailed knowledge of the porcine anatomy and physiology is a prerequisite for proper use of pigs as a teaching or an experimental model in interventional radiology. A systematic study of the radiological anatomy was undertaken in more than 100 female pigs aged 6-8 weeks. All studies were performed under general anesthesia in a single session. Animals were sacrificed at the end of the study. Selective angiographies were systematically obtained in all anatomical territories. In other animals CT and MRI examinations were performed and were correlated to anatomical sections and acrylic casts of the vascular structures. Endoscopical examinations of the upper gastrointestinal tract, including retrograde opacification of the biliary and pancreatic ducts, were added in selected animals. The main angiographic aspects of the brain, head and neck, thorax, abdomen, and pelvis were recorded. Similarities and differences in comparison with human anatomy are stressed. Potential applications in interventional radiology are indicated.

Animals↗
PubMed1998

Spirituality and nursing: toward an ontological understanding.

The epistemological basis for nursing knowledge and practice is now well established. However, the ontological dimensions of nursing have not been as fully considered. Although the spirituality of people is receiving attention in nursing literature, a deeper understanding of its relevance as an ontological dimension of nursing, is needed. This paper examines reasons and strategies for emphasising spirituality as an ontological component of nursing.

Holistic Nursing↗
PubMed1998

Weighted Census-based deprivation indices: their use in small areas.

BACKGROUND: The concept of deprivation refers to the conditions experienced by people who are poor, whereas the concept of poverty relates to the lack of income and other resources that make these conditions difficult to break away from. The usual Census-based deprivation indices are often based on equally weighted (and highly correlated) variables. This is in spite of the fact that different social groups have been shown in numerous studies to have differing probabilities of suffering from deprivation. A weighted deprivation index based on individual level data and Census data produces a more accurate and more easily understandable method of estimating deprivation within an area, as it reflects the differences between social groups. This paper will describe how a technique used by Gordon (J Epidemiol Commun Hlth 1995; 49(Suppl. 2): S39-S44) can be applied to smaller areas to give estimates of the number of deprived living within them, producing a weighted index. METHODS: Breadline Greenwich data together with Census data were used to estimate the percentage of poor households in Greenwich wards using similar methods to those of Gordon. RESULTS: The results produced were very similar to the numbers estimated using the Breadline Britain weightings but there were differences in individual weightings for some of the variables. CONCLUSION: Gordon's approach can be applied to smaller areas to give estimates of the number of deprived using the nationally derived weightings. More accurate local estimates, subject to the different local conditions, can be easily derived if a similar survey to the Breadline Britain survey is conducted locally.

Censuses↗
PubMed1997

WHO Study on the reliability and validity of the alcohol and drug use disorder instruments: overview of methods and results.

The WHO Study on the reliability and validity of the alcohol and drug use disorder instruments in an international study which has taken place in centres in ten countries, aiming to test the reliability and validity of three diagnostic instruments for alcohol and drug use disorders: the Composite International Diagnostic Interview (CIDI), the Schedules for Clinical Assessment in Neuropsychiatry (SCAN) and a special version of the Alcohol Use Disorder and Associated Disabilities Interview schedule-alcohol/drug-revised (AUDADIS-ADR). The purpose of the reliability and validity (R&V) study is to further develop the alcohol and drug sections of these instruments so that a range of substance-related diagnoses can be made in a systematic, consistent, and reliable way. The study focuses on new criteria proposed in the tenth revision of the International Classification of Diseases (ICD-10) and the fourth revision of the diagnostic and statistical manual of mental disorders (DSM-IV) for dependence, harmful use and abuse categories for alcohol and psychoactive substance use disorders. A systematic study including a scientifically rigorous measure of reliability (i.e. 1 week test-retest reliability) and validity (i.e. comparison between clinical and non-clinical measures) has been undertaken. Results have yielded useful information on reliability and validity of these instruments at diagnosis, criteria and question level. Overall the diagnostic concordance coefficients (kappa, kappa) were very good for dependence disorders (0.7-0.9), but were somewhat lower for the abuse and harmful use categories. The comparisons among instruments and independent clinical evaluations and debriefing interviews gave important information about possible sources of unreliability, and provided useful clues on the applicability and consistency of nosological concepts across cultures.

Adult↗
PubMed1997

The perception of flicker on raster-scanned displays.

Experiments have verified the observations of Corbett and White that people are more sensitive to flicker on raster-scanned displays (e.g., television and visual display terminals) if the field scan direction is changed from the conventional top-to-bottom direction to bottom to top, left to right, or right to left. When measured by means of the flicker fusion frequency (FFF), this effect is present only when normal eye movements are permitted. With fixation, the FFF is similar for all scan directions. The effect is demonstrated by the different frequencies at which a directional component is detected in the flicker (which we have called the rolling flicker threshold frequency, or RFTF); the RFTF is lower for top-to-bottom scanning. The effect does not appear to be associated with any asymmetry in eye movements or with eccentricity of the retinal image. The hypothesis that this difference is a consequence of adaptation to televisions and VDTs is supported by the observation that the effect's magnitude correlates with daily exposure time to televisions and VDTs and by a pilot study showing that the effect is reduced when one views a television scanned from bottom to top for 1 h.

Adult↗
PubMed1997

Walking a mile in their shoes... Symbolic interactionism for families living with severe mental illness.

1. With deinstitutionalization and changes in legal rights of patients, care of patients with severe mental illness has shifted from a hospital-based to a community-centered system. 2. Families often serve as an extension of the mental health system, providing important case management functions such as assessment, monitoring, crisis management, and advocacy. 3. Symbolic interactionism provides a framework for understanding the role of meaning in individual and family responses to the disruption of life that results from severe mental illness.

Adaptation, Psychological↗
PubMed1997

2,2'-Dithiobisbenzamides and 2-benzisothiazolones, two new classes of antiretroviral agents: SAR and mechanistic considerations.

Substituted 2,2'-dithiobisbenzamides and 2-benzisothiazolones were prepared and shown to possess low microM activity with high therapeutic indices against HIV-1, HIV-2 and SIV in cell culture. The mechanism of antiviral action was determined to be directed toward the nucleocapsid protein (NCp7), which contains two zinc fingers and plays vital roles in the viral life cycle. The "active sulfides" of this study cause the extrusion of zinc from these zinc fingers. Structure-activity relationships of the 2,2'-dithiobisbenzamides reveal that the disulfide bond and the ortho benzamide functional groups are essential for activity, with the best compounds having a carboxylic acid, carboxamide, or sulfonamide substituent. The 2-benzisothiazolones are formed from the disulfides both chemically and in vivo and their SAR mimics that of the 2,2'-dithiobisbenzamides. The antiviral activity of the disulfides may require cyclization to the isothiazolones. Two agents, PD 159206 and PD 161374, which showed good antiviral activity, physical properties, and excellent pharmacokinetics in mice, were selected for advanced studies.

Alkylation↗
PubMed1997

-(S)-Alpha-phenyl-2-pyridine-ethanamine Dihydrochloride-, a low affinity uncompetitive N-methyl-D-aspartic acid antagonist, is effective in rodent models of global and focal ischemia.

[(S)-Alpha-phenyl-2-pyridine-ethanamine dihydrochloride] (ARL 15896AR) is a low affinity uncompetitive N-methyl-D-aspartic acid receptor antagonist that was tested in animal models of anoxia and ischemia. Pretreatment of rodents with ARL 15896AR extended survival time during exposure to hypoxia. With the rat four-vessel occlusion model of global ischemia (20 min), oral dosing commencing at reflow, resulted in significant protection of the CA1 hippocampal neurons. ARL 15896AR was, however, ineffective in the rat two-vessel occlusion model and in the gerbil models of forebrain ischemia, the latter due to an inability to attain suitable plasma levels. In the spontaneously hypertensive rat model of middle cerebral artery occlusion (MCAO) (2 hr plus 22 hr reflow), acute dosing with ARL 15896AR (i.p.) beginning from 30 min before or up to 1 hr post-MCAO significantly reduced cortical infarct volume. The ability of ARL 15896AR to influence infarct size, as well as functional correlates was examined in SHR after 90 min of MCAO. T2 weighted magnetic resonance images taken at 2 and 6 days post-MCAO revealed significantly smaller lesion sizes in the group receiving injections with ARL 15896AR beginning 30 min after occlusion. Spontaneously hypertensive rats were subsequently tested (30-42 days post-MCAO) and found to be deficient in skilled use of the forepaws (staircase test). The contralateral forepaw was most severely impaired, however, ARL 15896AR treatment prevented motor impairment in only the ipsilateral forepaw. Histopathological examination of cortical infarct size was unremarkable between treated and control rats. The findings indicate that ARL 15896AR exhibits neuroprotection in global and focal models of ischemia

Animals↗
PubMed1996

Discovery of a novel protein modification: alpha-glycerophosphate is a substituent of meningococcal pilin.

Pili, which are filamentous protein structures on the surface of the meningitis-causing organism Neisseria meningitidis, are known to be post-translationally modified with substituents that affect their mobility in SDS/PAGE and which might play a crucial role in adherence and bloodstream invasion. Tryptic digests of pili were analysed by fast atom bombardment and electrospray MS to identify putative modifications. Serine-93 was found to carry a novel modification of alpha-glycerophosphate. This is the first time that alpha-glycerophosphate has been observed as a substituent of a prokaryotic or eukaryotic protein.

Amino Acid Sequence↗
PubMed1996

Nonpeptidic HIV protease inhibitors: 4-hydroxy-pyran-2-one inhibitors with functional tethers to P1 phenyl ring to reach S3 pocket of the enzyme.

A systematic study of tethering various groups on 6-phenyl ring of 4-hydroxy-6-phenyl-3-[(2-isopropylphenyl)thio]pyran-2-one was performed to increase the binding affinity with HIV protease. This tethering approach was aimed to fill S3 pocket of the enzyme. Thus, tethering hydrophilic groups resulted in more potent inhibitors. Similarly, various aromatic hydrophobic rings as well as heterocyclic rings were explored as tethering substituents to alter the physical properties as well as to enhance the binding affinity with HIV protease. Inhibitor 24, 4-hydroxy-3-[(2-isopropylphenyl)thio]-6-[4-(3-pyridinylmethoxy+ ++ ) phenyl]-2H-pyran-2-one, was evaluated as a prototypic lead structure to study various physical as well as pharmacological properties of this class of HIV protease inhibitors.

Cell Line↗
PubMed1996

Estimation of fetal lung volume using enhanced 3-dimensional ultrasound: a new method and first result.

OBJECTIVE: To measure fetal lung volume using a computer based, enhanced, 3-dimensional ultrasound imaging system. DESIGN: An observational study. SETTING: The Fetal Medicine Unit at Guys Hospital, London. PARTICIPANTS: Twenty healthy women with a singleton pregnancy between 24 and 36 weeks of gestation were scanned on one occasion during pregnancy using an ultrasound based 3-dimensional imaging system. All delivered at term with weights above the 10th centile for gestation. RESULTS: Total lung volume increased exponentially with gestational age. Right lung volume measured consistently greater than left lung volume. CONCLUSIONS: The use of this new enhanced 3-dimensional imaging system allows for estimations of fetal lung volume. Preliminary data confirm that fetal lung volume, measured by a computerised 3-dimensional ultrasound imaging system increased exponentially with gestational age. The use of this system has obvious application in the further study of lung growth in utero and possible clinical application in disease states where fetal lung growth may be impaired.

Female↗
PubMed1996

Measuring management potential.

This article provides a brief introduction to instruments that may be used to measure management potential in persons being considered for administrative positions. Instruments that measure aspects of leadership, power, personality, conflict, and organizational climate are discussed. An overview of each instrument is provided as well as data on the type of test, time to complete, cost, and purchasing information. While objective tests such as these are useful in assessing individual suitability for management positions, we advise that they be used prudently and judiciously.

Administrative Personnel↗
PubMed1996

Direct cochlear nerve action potentials as an aid to hearing preservation in middle fossa acoustic neuroma resection.

A new application of auditory evoked potentials using direct cochlear nerve action potentials (CNAPs) for monitoring middle fossa acoustic neuroma resection with attempted hearing preservation is described. Twenty patients have been studied to date. With this technique, a monitoring electrode is secured between the floor of the internal auditory canal and the dura adjacent to the cochlear nerve in an extradural location. Standard auditory evoked potential techniques with click stimuli and microelectrical recording allow observation of nearfield waveforms in seconds versus several minutes required for farfield potentials recorded from the scalp. Advantages of this technique over auditory brainstem response monitoring may include nearly real time measurement of potentials, improved surgeon learning curve and possibly higher rates of hearing preservation, and applicability to all patients undergoing hearing-preservation surgery independent of presence or absence of ABR tracing. Immediate changes in amplitude and latency of waveforms appear to compare with reversible and irreversible intraoperative auditory system damage, thereby guiding surgical maneuvers.

Acoustic Stimulation↗
PubMed1995

Mapping the homotypic binding sites in CD31 and the role of CD31 adhesion in the formation of interendothelial cell contacts.

CD31 is a member of the immunoglobulin superfamily consisting of six Ig-related domains. It is constitutively expressed by platelets, monocytes, and some lymphocytes, but at tenfold higher levels on vascular endothelial cells. CD31 has both homotypic and heterotypic adhesive properties. We have mapped the homotypic binding sites using a deletion series of CD31-Fc chimeras and a panel of anti-CD31 monoclonal antibodies. An extensive surface of CD31 is involved in homotypic binding with domains 2 and 3 and domains 5 and 6 playing key roles. A model consistent with the experimental data is that CD31 on one cell binds to CD31 on an apposing cell in an antiparallel interdigitating mode requiring full alignment of the six domains of each molecule. In addition to establishing intercellular homotypic contacts. CD31 binding leads to augmented adhesion via beta 1 integrins. The positive cooperation between CD31 and beta 1 integrins can occur in heterologous primate cells (COS cells). The interaction is specific to both CD31 and beta 1 integrins. Neither intercellular adhesion molecule-1 (ICAM-1)/leukocyte function-associated antigen-1 (LCAM-1) nor neural cell adhesion molecule (NCAM)/NCAM adhesion leads to recruitment of beta 1 integrin adhesion pathways. Establishment of CD31 contacts have effects on the growth and morphology of endothelial cells. CD31(D1-D6)Fc inhibits the growth of endothelial cells in culture. In addition, papain fragments of anti-CD31 antibodies (Fab fragments) disrupt interendothelial contact formation and monolayer integrity when intercellular contacts are being formed. The same reagents are without effect once these contacts have been established, suggesting that CD31-CD31 interactions are critically important only in the initial phases of intercellular adhesion.

Antigens, Differentiation, Myelomonocytic↗