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Rayner BL, Williams DS, Oliver S. Inoculation of peritoneal dialysate fluid into blood culture bottles improves culture rates. S Afr Med J 1993; 83:42-3. [PMID: 8424203] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
The aim of the study was to determine if direct inoculation of peritoneal fluid into Bactec blood culture bottles would improve the positive bacteriological yield compared with conventional techniques in continuous ambulatory peritoneal dialysis (CAPD) patients with peritonitis. All patients presenting with suspected peritonitis had peritoneal fluid injected directly into aerobic and anaerobic Bactec blood culture bottles as well as into sterile culture tubes. Thirty-seven paired samples were analysed. Twenty conventional cultures (54%) were positive compared with 33 (89%) done according to the Bactec system (P < 0.002). In only 1 case did the former technique prove superior. Direct inoculation of peritoneal fluid into Bactec blood culture bottles is therefore superior to conventional methods and has obvious therapeutic implications.
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Coombs LM, Oliver S, Sweeney E, Knowles M. Immunocytochemical localization of c-erbB-2 protein in transitional cell carcinoma of the urinary bladder. J Pathol 1993; 169:35-42. [PMID: 8094432 DOI: 10.1002/path.1711690107] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The level of expression and cellular localization of the c-erbB-2 gene product in transitional cell carcinoma of the urinary tract is controversial. Analysis of the c-erbB-2 gene structure and comparison of its expression in the same cells by Southern, Northern and immunoblotting, and by immunocytochemistry minimize the errors of interpretation inherent in one technique. Such a 'correlative study' has been performed on tumours from 82 patients. c-erbB-2 gene amplification was detected in 14 per cent of initial tumours and was associated with grade (P < 0.001). Raised levels of mRNA were seen in those tumours with increased gene copy number and in 13 per cent of the remainder. Immunoblotting detected the expected 185 kD immunoreactive protein and a 155 kD protein associated with high gene copy number. Immunocytochemistry localized c-erbB-2 immunoreactivity to the cell membrane and cytoplasm, and the latter predominated. Four antibodies to c-erbB-2 (AB-3, 21N, pAb 1, and NCL CB11) were compared on contiguous sections of the same tumour and showed the same pattern of immunoreactivity. Similarly, analyses carried out in three independent laboratories identified the same cellular localization. Membrane and cytoplasmic immunoreactivity was demonstrated in all tumours with gene amplification or increased mRNA levels and in 40 per cent of the remaining tumours. We showed that immunocytochemistry requires careful standardization of techniques and quantitation between different groups. However, despite variations in the intensity of immunoreactivity, the total number of positive cells remained constant. Therefore quantitation must be based on the number of positive cells and, ideally, their immunoreactive content relative to normal and positive tissue controls.
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Hopkins P, Shaw R, Acik L, Oliver S, Eddy AA. Fluorocytosine causes uncoupled dissipation of the proton gradient and behaves as an imperfect substrate of the yeast cytosine permease. Yeast 1992; 8:1053-64. [PMID: 1293884 DOI: 10.1002/yea.320081208] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
At pH 5-6 ATP-depleted washed cell preparations of strain NC233-10b[pII4-9], in which the cytosine permease was overexpressed, absorbed cytosine, hypoxanthine or fluorocytosine stoichiometrically with, respectively, about 1, 1.4 and 5 proton equivalents. The cellular pH fell proportionately. The membrane depolarization caused by each compound was assayed in the presence of glucose with a voltage-sensitive dye and increased in the same order. Fluorocytosine significantly lowered the growth yield that a 'petite' strain of the yeast formed at limiting glucose concentrations. At pH 5.6 with extracellular [K+] below 1 mM, each of the three substrates was accumulated about 200-fold from a dilute solution at the expense of the proton gradient. This concentration ratio corresponds to a solute gradient (delta mu(s)) of 13 kJ mol-1. Raising [K+]o systematically lowered the substrate accumulation ratio and delta muH. The mean ratio delta mu(s)/delta muH was 0.82 for all three substrates. It was concluded that whereas the behaviour of cytosine approximated to that expected for a symport of unit proton stoichiometry, the absorption of protons with fluorocytosine and, to a lesser extent, hypoxanthine, was only partly conserved as useful work. A possible mechanism of this novel phenomenon is outlined.
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Mewes HW, Oliver S, Goffeau A. Response
: The Smithsonian and Sheep Hunting. Science 1992; 256:1378-9. [PMID: 17791593 DOI: 10.1126/science.256.5062.1378-b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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131
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Norman IJ, Redfern SJ, Tomalin DA, Oliver S. Developing Flanagan's critical incident technique to elicit indicators of high and low quality nursing care from patients and their nurses. J Adv Nurs 1992; 17:590-600. [PMID: 1602075 DOI: 10.1111/j.1365-2648.1992.tb02837.x] [Citation(s) in RCA: 149] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
This paper discusses a development of Flanagan's critical incident technique (CIT) to elicit indicators of high and low quality nursing from patients and their nurses on medical, surgical and elderly care wards. Stages in undertaking the CIT are identified and presuppositions held by most researchers about the nature of the technique are identified. The paper describes how the authors moved to a different set of presuppositions during the course of the study. Preliminary analysis of interview transcripts revealed that critical incidents need not always be demarcated scenes with a clear beginning and end, but may arise from respondents summarizing their overall experience within their description of one incident. Characteristically respondents were unable to give a detailed account of such incidents but validity may be established by the fact that respondents appear to recount what actually happened as they saw it, and what they said was clearly important to them. The researchers found that the most appropriate basic unit of analysis was not the incident itself but 'happenings' revealed by incidents that are 'critical' by virtue of being important to respondents with respect to the quality of nursing care. The importance of CIT researchers achieving an understanding of the 'meaning' of critical happenings to respondents is emphasized. Analysis of the interview transcripts is facilitated by the use of INGRES, a relational database computer program which should enable a 'personal theory' of quality nursing for each respondent, both patients and nurses, to be described. The study suggests that the CIT is a flexible technique which may be adapted to meet the demands of nursing research. If carefully applied, the CIT seems capable of capitalizing on respondents' own stories and avoids the loss of information which occurs when complex narratives are reduced to simple descriptive categories. Patients and nurses have unique perspectives on nursing and their views are of primary importance in understanding what quality means with respect to the interpersonal processes that are integral to nursing care. This paper discusses the identification of indicators of quality nursing from interviews with patients and nurses using the authors' development of Flanagan's critical incident technique.
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Norman I, Redfern S, Tomalin D, Oliver S. Applying triangulation to the assessment of quality of nursing. NURSING TIMES 1992; 88:43-6. [PMID: 1538979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The claim that generic quality assessment instruments provide an objective assessment of quality of nursing care is questioned. Recent research suggests that most instruments are in need of extensive validity testing, particularly in relation to the concepts that they purport to assess. This paper outlines a research study designed to test the validity of the generic quality assessment instruments, Monitor, Senior Monitor and Qualpacs. In the absence of an independent criterion of quality against which to validate these instruments we propose a multiple triangulation research strategy in order to achieve the goals of 'confirmation' and 'completeness' within the same research design. The research incorporates approaches that purport to focus on quality of nursing care that are complementary to the generic instruments. We pay particular attention to the meanings of quality of nursing to those most closely involved and in positions of expertise--that is, nurses and patients. Comparisons between scores from the generic instruments and data generated by these complementary approaches will enable a more accurate picture of the validity of the generic instruments to emerge. The research should also increase our understanding of the meaning of quality in relation to nursing care.
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Hill AJ, Oliver S, Rogers PJ. Eating in the adult world: the rise of dieting in childhood and adolescence. BRITISH JOURNAL OF CLINICAL PSYCHOLOGY 1992; 31:95-105. [PMID: 1559122 DOI: 10.1111/j.2044-8260.1992.tb00973.x] [Citation(s) in RCA: 115] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Dieting is a common practice among adolescent girls. Recent research suggests that adolescent dieting may not be benign and that it is becoming more frequent in younger age groups. The present study investigated dieting motivation and the underlying attitudes to body weight and shape in two age groups. Eighty-four nine-year-old and 86 14-year-old girls from the same school completed assessments of dietary restraint, body esteem, body satisfaction and body figure preferences. The girls' body weight and height were also measured. The distribution of restraint scores revealed individuals from both age groups in every category of dieting motivation. Subjects in the upper and lower quartiles of the restraint distribution were identified and compared on the other measures. The highly restrained girls expressed low body esteem and discontent with their body build, weight and certain regions of their bodies. Furthermore, their 'ideal' body shape was significantly slimmer than their perceived current body shape, and slimmer even than that of the non-dieters. This pattern held for both the nine- and 14-year-olds, of whom half of each age group were of average or below average weight index for their age. The appearance of these dispositions and behaviours by the age of nine, or possibly earlier, may result in a marked increase in future clinical eating problems and disorders.
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Shoaf J, Oliver S. Efficacy of normal saline injection with and without heparin for maintaining intermittent intravenous site. Appl Nurs Res 1992; 5:9-12. [PMID: 1570963 DOI: 10.1016/s0897-1897(05)80077-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
This study evaluated the effectiveness of normal saline versus normal saline containing 10 U per 1 mL heparin for preventing loss of an intermittent intravenous site (heparin lock). The sample consisted of 260 surgical patients from a general surgery and a cardiovascular surgery nursing unit at a tertiary care hospital. Results indicated that heparinized saline is not needed to maintain the patency of an intermittent intravenous site, and the use of saline solution alone is less irritating, causes less phlebitis, is less expensive to patients, and saves nursing time.
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Temple GS, Oliver S, Wilson JA. Detection of micro-organisms using a two bottle blood culture system: a twelve month study. MEDICAL LABORATORY SCIENCES 1991; 48:178-82. [PMID: 1787773] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Over a twelve month period the isolation rate of pathogens, frequency of isolation of non-significant organisms, and time taken to detect positive cultures from a two-bottle blood culture system were analysed. Of 6916 blood cultures collected, 978 organisms were isolated from 863 cultures, 540 organisms being considered clinically significant and the majority (81%) being isolated within 48 h. Our results showed that use of more than one bottle increased the general isolation rate, with both bottles facilitating growth independently. This situation was particularly apparent in the cases of Haemophilus influenzae and Neisseria meningitidis, which showed that using the system alone only 76% and 33% (respectively) of the total number of strains would have been isolated. The results of this study reinforce the need for a second bottle containing a suitable culture medium.
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Shenai JP, Major CW, Gaylord MS, Blake WW, Simmons A, Oliver S, DeArmond D. A successful decade of regionalized perinatal care in Tennessee: the neonatal experience. J Perinatol 1991; 11:137-43. [PMID: 1890472] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
We hypothesized that successful implementation of regionalized perinatal care would result in early identification and antenatal referral of high-risk neonates, and also improved stabilization before and during transport of those transferred postnatally. We conducted a retrospective study of demographic characteristics and transport outcome in two defined groups of neonates transported to regional perinatal centers in Tennessee, one group (n = 218) from the first year of regionalization (1975), and a second group (n = 261) from the 12th year (1986). The percentage of outborn infants decreased, from 50% of all admissions in 1975 to 22% in 1986 (P = .005). Likewise, the percentage of low-birthweight neonates transported after birth decreased, from 59% of all transports to 32% (P = .002). The frequency of stabilization measures performed before and during transport increased between study years (intravenous line placement: 12% to 58%, P = .0001; assisted ventilation: 10% to 33%, P = .001). The incidence of complications during transport decreased between study years (cyanosis: 25% to 8%, P = .0001; hypothermia: 30% to 3%, P = .0001; acidemia: 33% to 13%, P = .011). Both transport-related mortality and neonatal mortality decreased between study years (2.8% to 0.8%, P = .043; 17% to 7%, P = .0001, respectively). We conclude that regionalization during its first decade has been successful in improving perinatal care in Tennessee as indicated by favorable changes in referral patterns and improved outcome of transported neonates.
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138
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Oliver S, Redfern SJ. Interpersonal communication between nurses and elderly patients: refinement of an observation schedule. J Adv Nurs 1991; 16:30-8. [PMID: 2005287 DOI: 10.1111/j.1365-2648.1991.tb01494.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The aim of the study was to refine and improve the inter-observer reliability of an observation schedule, developed by Le May & Redfern, designed to record the amount and type of nurse-patient interpersonal communication. The new technique involved observation of non-verbal interactions using a portable computer programmed as an event recorder and a tape recorder to record conversation. The observation schedule was employed in an acute/rehabilitation care of the elderly ward and inter-observer reliability was tested on two occasions. The second observer used a handwritten version of the schedule. Reliability coefficients were acceptable (greater than or equal to 0.60 or greater than or equal to 70% agreement) for all the schedule components although the recording of non-verbal response was inadequate. Use of the portable computer produced no additional benefits over the handwritten schedule. The observation confirmed previous research which found that relatively little expressive touch takes place between nurses and elderly patients. A simplified version of the handwritten schedule together with tape-recording of verbal communication is likely to increase reliability.
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139
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Bass DH, Oliver S, Bornman PC. Pseudomonas septicaemia after endoscopic retrograde cholangiopancreatography--an unresolved problem. S Afr Med J 1990; 77:509-11. [PMID: 2188380] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Over a 6-month period 5 patients with obstructive jaundice developed Gram-negative septicaemia, all within 48 hours of undergoing endoscopic retrograde cholangiopancreatography. The sepsis proved fatal in 3 patients, despite prompt decompression of the obstructed biliary system. In all cases the organism responsible was Pseudomonas aeruginosa and the source of infection appeared to be a contaminated water-bottle attached to the endoscopic apparatus. This report highlights the importance of disinfection techniques and reviews the present situation in respect of antibiotic prophylaxis.
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Abstract
This article presents information related to conceptualizing, initiating, and maintaining a private practice in the music therapy field. The author discusses her experience in establishing Music Therapy Services of Arizona (MTSA), an independent agency for providing services in the Phoenix metropolitan area. Contents include a description of the agency's concept and service provision and a discussion of practical business considerations for therapists considering private practice.
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141
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Nerubay J, Oliver S, Volpin G, Katznelson A. Segmental reconstruction of the femoral shaft. ORTHOPAEDIC REVIEW 1987; 16:755-6. [PMID: 3503979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
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142
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Beale IL, Matthew PJ, Oliver S, Corballis MC. Performance of disabled and normal readers on the Continuous Performance Test. JOURNAL OF ABNORMAL CHILD PSYCHOLOGY 1987; 15:229-38. [PMID: 3611521 DOI: 10.1007/bf00916351] [Citation(s) in RCA: 33] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Twelve-year-old reading-disabled children of normal intelligence were compared on the Continuous Performance Test with two control groups of normal intelligence and reading ability either of the same age or of the same reading age as the reading-disabled group. Signal-detection analysis showed that the reading-disabled were more conservative than chronological-age controls in their willingness to identify the target letter sequence. Although this conservative performance was shared by the reading-age controls, the reading-disabled suffered an additional handicap of relatively frequent anticipatory errors. Groups also differed on a sensitivity measure, suggesting a deficit in working memory in the reading-disabled children.
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143
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Potgieter PD, Linton DM, Oliver S, Forder AA. Nosocomial infections in a respiratory intensive care unit. Crit Care Med 1987; 15:495-8. [PMID: 3568713 DOI: 10.1097/00003246-198705000-00008] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
A total of 250 consecutive admissions to an open-plan respiratory ICU were analyzed prospectively to identify the incidence of secondary hospital-acquired infections and possible predisposing factors. Despite preventative measures and a restricted antibiotic policy, 23.6% of patients developed secondary infections. Patients admitted after multiple trauma were the only diagnostic category of patients who showed a significantly increased incidence of secondary infections. The length of hospitalization and number of patients who had intubations or tracheostomies was higher in the group with secondary infection; the causal relationship was difficult to establish. Patients who were not intubated or tracheostomized did not develop secondary infection. Prior administration of antibiotics did not appear to influence the incidence of secondary infection. There was a significant increase in secondary infections in patients with a higher therapeutic intervention scoring system score. The predominant pathogens cultured were highly resistant Gram-negative organisms, particularly Acinetobacter sp. and Pseudomonas sp. Staphylococcus aureus was the most common Gram-positive pathogen. The ICU course was probably prolonged by the complication of nosocomial infection, which may have contributed to the deaths.
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144
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Lin E, Oliver S, Lieberman Y, Nerubay J, Bubis JJ, Blankstein A. Osteoblastoma of the sternum. ARCHIVES OF ORTHOPAEDIC AND TRAUMATIC SURGERY. ARCHIV FUR ORTHOPADISCHE UND UNFALL-CHIRURGIE 1987; 106:132-4. [PMID: 3566508 DOI: 10.1007/bf00435429] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Osteoblastoma has become a well defined bone tumor since its first description by Jaffe and Mayer in 1932. This tumor was considered to occur in almost any bone of the skeleton. Only one previous case of sternal osteoblastoma was described in the literature. Herein we report, as far as we know, the second reported case of osteoblastoma in the sternum, as an isolated tumor.
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Caspi I, Ezra E, Oliver S, Lin E, Lotan G, Horoszowski H. Treatment of avulsed clavicle and recurrent subluxations of the ipsilateral shoulder by dynamic fixation. THE JOURNAL OF TRAUMA 1987; 27:94-5. [PMID: 3806725 DOI: 10.1097/00005373-198701000-00021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
A new operative approach is presented for treatment of fractured distal end of clavicle associated with recurrent anterior shoulder subluxations. One case is presented in which open reduction of the fractured clavicle and stabilizing the anterior shoulder joint were accomplished by transfer of the coracoid process with its attached muscles under the subcapularis muscle onto the clavicle. The operation was followed by complete reduction of the fracture and a stable shoulder joint.
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146
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Lin E, Oliver S, Caspi I, Ezra E, Bubis JJ, Nerubay J. Hip arthroplasty in quiescent mycobacterial infection of hip. ORTHOPAEDIC REVIEW 1986; 15:232-6. [PMID: 3135526] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Three patients underwent hip arthroplasty--one total hip replacement and two, Thompson's hemiarthroplasty. The diagnosis was degenerative joint disease and subcapital fracture of the femur, respectively. Histologic and bacteriologic examination revealed mycobacterial infection. None of the patients had a past history of mycobacterial infection. In one instance, there was a reactivation of the infection eight months following surgery, which was treated successfully by antituberculosis drugs.
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147
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Lin E, Oliver S, Nerubay J, Caspi I, Vered Z, Katznelson A. The cardiac pacemaker patient with a femoral neck fracture. ORTHOPAEDIC REVIEW 1986; 15:95-7. [PMID: 3453452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
More than half the patients with permanent cardiac pacemakers (PCPMs) are over the age of 70 years. Patients in this age group are also more susceptible to fractures of the femoral neck requiring surgical intervention. The authors studied five patients with PCPMs who underwent surgery for femoral neck fracture. They discuss the special precautions necessary during surgery to prevent electromagnetic interference with the cardiac pacemaker as well as the special management of these patients.
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148
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McKeran RO, Firth G, Oliver S, Uttley D, O'Laoire S. A potential application for the intracerebral injection of drugs entrapped within liposomes in the treatment of human cerebral gliomas. J Neurol Neurosurg Psychiatry 1985; 48:1213-9. [PMID: 2418156 PMCID: PMC1028604 DOI: 10.1136/jnnp.48.12.1213] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
After intravenous injection of therapeutic doses of bleomycin only small amounts could be measured in glioma tissue obtained at operation in patients with malignant gliomas and the drug was rapidly cleared from the blood (T1/2 = 2 hrs). Negatively charged liposomes injected through Ommaya reservoirs into the glioma tumour bed were tolerated without observable side effect. The appearance of bleomycin in the blood and urinary clearance after intracerebral injection of bleomycin entrapped within negatively charged liposomes through an Ommaya reservoir in patients with malignant gliomas was decreased as compared with levels when free bleomycin was injected. These preliminary observations suggest a role of drugs entrapped within liposomes as a depot preparation in the treatment of human cerebral gliomas.
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149
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Oliver S, Bubley G, Crumpacker C. Inhibition of HSV-transformed murine cells by nucleoside analogs, 2'-NDG and 2'-nor-cGMP: mechanisms of inhibition and reversal by exogenous nucleosides. Virology 1985; 145:84-93. [PMID: 2990104 DOI: 10.1016/0042-6822(85)90203-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
A murine cell line transformed with HSV TK (LH-1) exhibits a greatly enhanced cytotoxicity to the nucleoside analog 9-[(2-hydroxy-1-(hydroxymethyl)ethoxy) methyl]guanine (2'-NDG) as compared to the parental LM cell line (I50 LH-1 = 0.4 microM; I50 LM = 44.4 microM). Toxicity of 2'-NDG for LH-1 and LM is reversed only by the addition of 100 microM thymidine (dThd), indicating that 2'-NDG is a substrate for the viral and cellular TK. In LM(TK-) cells--murine cells expressing no TK activity, 2'-NDG cytotoxicity is partially reversed only with dGuo. A cyclic phosphate derivative of 2'-NDG, 2'-nor-cGMP, contains a phosphodiester bond, is also taken up by cells, and does not depend on viral TK for activation. LH-1 cells and LM(TK-) cells are inhibited by similar concentrations of this analog (5.1 and 4.1 microM, respectively). In all three cell lines (LM, LH-1, LM(TK-], the toxicity of 2'-nor-cGMP is significantly reversed with dGuo or cyclic dGMP. This pattern of reversal differs significantly from that observed with 2'-NDG, suggesting that 2'-nor-cGMP is metabolized as a guanosine analog, similar to acyclovir, in LM and LM(TK-) cells. These results indicate that a cyclic monophosphate analog of 2'-NDG can be activated independently of viral TK expression and that cellular metabolic pathways resulting in elevated dGTP concentrations are important for reversal of toxicity induced by guanosine-like nucleoside analogs.
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150
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Ruben LN, Buenafe A, Oliver S, Malley A, Barr K, Lukas D. Suppression in Xenopus laevis: thymus inducer, spleen effector cells. Immunology 1985; 54:65-70. [PMID: 3156089 PMCID: PMC1454854] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Studies were carried out on suppressor function in the amphibian Xenopus laevis, the South African clawed toad. Suppression by the thymus of haemagglutinin (HA) production by spleen is antigen-dependent, partially specific and not MHC-restricted in this species (Ruben, Buenafe & Seivert, 1983). Three questions were considered in this study. Does the thymus effect suppression by stimulating peripheralized spleen effector cells, or do effector cells reside within the thymus? Do macrophages participate in the induction and/or expression of thymus-dependent suppressor function? Can thymus suppressor and helper functions be distinguished by using irradiation treatment? The capacity of immunized thymus to suppress HA when co-cultured with spleen fragments from immunized, cyclophosphamide (CyP)-injected animals was tested. Immunized thymus failed to suppress the high levels of HA production by spleen fragments from CyP-treated, immunized donors. Colloidal carbon injection resulted in blockade of macrophage function, and both the capacity of thymuses to suppress and of spleens to be suppressed in co-cultures. Finally, the effect of thymus exposure to gamma-irradiation in vitro was tested using autogeneic thymus/spleen combinations. This enabled the visualization of thymic helper function, which is MHC-restricted in Xenopus (Bernard et al., 1981). Four dosages of irradiation were tested after antigen challenge. The highest HA titres were produced by spleen co-cultures with thymuses which had received 1000 rads. We conclude that suppression of HA production in spleen is not the result of thymus suppressor effector cells, but that suppressor function is mediated by thymus inducer cells which stimulate suppressor effectors in spleen. Both the thymic inducers and effectors in the spleen are sensitive to CyP and macrophage blockade. Our studies further suggest that we are able to distinguish between the thymic functions of help and suppression in Xenopus by taking advantage of their differential sensitivities to irradiation. While it has been postulated, on other grounds, that suppression was one of the earliest thymic regulatory functions to have evolved (L.N. Ruben & R.H. Clothier, submitted), here we suggest the presence of sequential activities of more than one cellular subset, as early in evolution as the primitive anuran (tail-less) amphibia.
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