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Biomedical subjects

J Russell

Publications and source records attributed to J Russell.

At least 181 records · Page 10Linked to original sources
PubMed1994

Prognostic implications of normal exercise tomographic thallium images in patients with angiographic evidence of significant coronary artery disease.

This study examines the prognostic implications of normal exercise tomographic thallium images in medically treated patients with angiographic evidence of coronary artery disease (CAD). There were 97 patients aged 60 +/- 10 years; 52 had 1-, 30 had 2-, and 15 had 3-vessel CAD (> or = 50% diameter stenosis). The exercise test was submaximal in 51 patients (53%); ST-segment depression during exercise occurred in 20 patients (21%), and angina during exercise occurred in 23 patients (24%). Most patients (71%) were receiving antianginal therapy. During a mean follow-up of 32 months, only 3 patients had cardiac events: 2 died of cardiac causes and 1 had nonfatal myocardial infarction (event rate 1.1%/year). None of those 3 patients had positive ST response during exercise. Thus, medically treated patients with CAD (including those with multivessel CAD) have a benign prognosis in the presence of normal exercise thallium images. These results have important implications in patient management and cost of health delivery.

Coronary Angiography↗
PubMed1994

Alteration of the erythrocyte glutathione redox balance by N-acetylcysteine, captopril and exogenous glutathione.

The effect of the thiol containing compounds N-acetylcysteine and captopril on glutathione metabolism in human erythrocytes has been investigated non-invasively using 1H spin echo NMR. N-Acetylcysteine was found to increase the reduced form of glutathione while captopril increased the oxidized form, but no changes in the total glutathione concentration were observed. Incubation of the cells with buthionine sulphoximine to inhibit de novo glutathione synthesis did not affect the response. The results show that these compounds act by altering the redox balance of glutathione rather than by stimulating its synthesis, and that their mechanisms of action are different, and not simply due to the presence of the thiol group.

Acetylcysteine↗
PubMed1994

Synthesis, oral bioavailability determination, and in vitro evaluation of prodrugs of the antiviral agent 9-[2-(phosphonomethoxy)ethyl]adenine (PMEA).

A series of phosphonate prodrugs were evaluated in an attempt to increase the oral bioavailability of the anti-HIV agent 9-[2-(phosphonomethoxy)ethyl]adenine (PMEA; 1). The majority of the bis(alkyl ester) and bis(alkyl amide) prodrugs were prepared by alcohol or amine displacement of dichlorophosphonate 2. Basic hydrolysis of the bis(esters) or bis(amides) provided the corresponding monoesters or monoamides. Synthesis of bis[(acyloxy)alkyl] phosphonates 10a-c was accomplished by alkylation of PMEA with the appropriate chloromethyl ether in the presence of N,N'-dicyclohexylmorpholinecarboxamidine. The systemic levels of PMEA following oral administration of a PMEA prodrug to rats were determined by measuring the concentration of PMEA in the urine for 48 h after administration of the prodrug. The oral bioavailability of PMEA employing this method was determined to be 7.8%. Oral dosing with bis(alkyl) phosphonates 3a,b resulted in apparent absorption of the prodrugs (> or = 40%), although neither of the esters were completely cleaved to liberate the parent phosphonate PMEA. The mono(alkyl esters) 7a-e and 8a,b exhibited poor oral bioavailability (< or = 5%). Phosphonamides 5, 6, and 9 were unstable under acidic conditions and provided levels of PMEA comparable to the parent compound after oral administration. Bis[(acyloxy)alkyl] phosphonates 10a-c demonstrated significantly improved oral bioavailabilities of 17.6%, 14.6%, and 15.4%, respectively. When evaluated in vitro against HSV-2, (acyloxy)alkyl phosphonates 10a-c were greater than 200-fold more active than PMEA.

Adenine↗
PubMed1994

Total body nitrogen as a predictor of clinical status in anorexia nervosa.

It has been demonstrated that clinical outcome is positively correlated with depletion of total body nitrogen (TBN) and therefore of body protein in certain serious medical conditions such as cystic fibrosis or patients receiving dialysis for chronic renal failure. Patients with anorexia nervosa are not suffering from medical illness per se yet the illness can be chronic and severely debilitating requiring numerous hospitalizations for refeeding and/or management of medical complications. The prediction of chronicity remains an important and difficult issue that this study seeks to address by examining the correlation between several clinical indices in 18 patients suffering from anorexia nervosa with parameters of body composition, namely TBN and percentage body fat. TBN was measured using the technique of in vivo neutron-activation analysis (IVNAA) and expressed as nitrogen index. Percentage body fat was estimated using skinfold measurements. The highest correlation was between nitrogen index and number of hospitalizations (r = -.80). The data support a relationship between depletion of body nitrogen/protein and chronicity in anorexia nervosa.

Adolescent↗
PubMed1994

The effect of adult belt laws and other factors on restraint use for children under age 11.

We used data from 11 states (5,449 respondents) to examine the association between self-reported consistent use of occupant restraints for children under 11 years of age and presence of adult belt-use laws while controlling for other factors. Self-reported safety belt use by adults, age of youngest child in the household (child restraint use decreased with increasing age), and adult educational attainment were significant predictors of child restraint use; respondent age, race/ethnicity, sex, marital status, household income, and employment status were not. Adult and child occupant restraint use was higher in states with an adult safety belt law than in states without such a law.

Child↗
PubMed1994

Evidence for executive dysfunction in autism.

A group of young people with autism (ranging in ability from high functioning to moderately learning disabled), and ability-matched control groups of (i) non-autistic individuals with moderate learning disabilities, and (ii) normally developing children, were presented with two tests of executive function: the Intra-dimensional/Extra-dimensional set-shifting task and the Tower of London planning task. These tests were graded in difficulty and included internal control measures. On each task, the autistic group was differentially impaired with respect to both control groups. Moreover, this impairment was specific to the stages of each task which placed greatest demands upon executive control. This evidence for executive dysfunction in autism is discussed in the context of Norman and Shallice's (Centre for Human Information Processing Technical Report 99, 1980) "Supervisory Attentional System" model of frontal function.

Adolescent↗
PubMed1994

The assessment of the HO. scavenging action of therapeutic agents.

A new method is reported for the assessment of the HO. scavenging action of therapeutic agents. It is based on the photolysis of zinc oxide and has a detection limit of 3.3%. The scavenging order of the compounds tested was penicillamine > rentiapril > ascorbic acid > cysteine > glutathione > thiomalic acid > N-acetylcysteine > myocrysin > methionine. None were as effective as DMSO. It is argued that these compounds can have an in vivo protective effect where HO. is produced from oxidant producing cells, thus limiting radical induced damage.

Azo Compounds↗
PubMed1994

N-myc gene copy number in neuroblastoma cell lines and resistance to experimental treatment.

The N-myc oncogene is amplified in approximately 30% of neuroblastomas. It is well established that cases of neuroblastoma with amplified N-myc have markedly poorer prognosis than those in which N-myc copy number is not elevated. The mechanism for this association is not known but may be related to cellular resistance to radiation or cytotoxic drugs. Seven human neuroblastoma cell lines were used to investigate the relationship between N-myc copy number or expression and sensitivity to ionising radiation and to cisplatin. N-myc copy number was assessed by Southern blotting and hybridisation using the p-Nb1 probe. The signal produced by DNA from the cell lines was compared with that of single copy N-myc from normal human placental DNA. A range of N-myc copy numbers from 1 to 800 was found. Expression levels of N-myc mRNA were compared by "dot blotting" and subsequent hybridisation to the p-Nb1 probe. Radiosensitivity was assessed by surviving fraction at 2 Gy (SF2) following 60Co gamma irradiation. Values ranged from 0.13 to 0.52. Sensitivity to cisplatin was indicated by comparison of isoeffective concentrations (concentration required to produce 1 log cell kill). These ranged from 7.5 to 13 microM. Cisplatin studies showed a correlation between N-myc copy number (though not expression) and resistance to this drug. If this relationship is causal it may explain why treatment fails in those patients with an elevated N-myc copy number. However, no correlation was found between N-myc copy number or expression and sensitivity to radiation. It is possible that N-myc amplification confers resistance to some but not all treatments used in the therapy of neuroblastoma. Further investigations along these lines may lead to the identification of agents which are most appropriate for the treatment of neuroblastoma with amplified N-myc gene.

Blotting, Southern↗
PubMed1994

Role analysis of the advanced practice nurse using the Neuman Health Care Systems Model as a framework.

The role of the advanced practitioner of nursing is perceived and operationalized differently from practice setting to practice setting. These differences should compel practitioners to analyze and differentiate role expectations within specific practice situations. The Neuman Health Care Systems Model provides a systematic framework for role analysis, development, enactment, and evaluation. The analysis should serve to decrease role stress, strain, and ambiguity while ultimately increasing role implementation success. The purposes of this article are: (a) to describe the general systems theory that is the basis of the Neuman model, (b) to describe the Neuman Health Care Systems Model to provide a basis for role analysis, and (c) to provide a structure for role analysis of the CNS. The benefit of a systematic microanalysis of the role of the CNS will be to develop a template to be used in the analysis of a particular position in the real world.

Humans↗
PubMed1994

Inhibition of parathyroid hormone secretion by amino-terminal chromogranin peptides.

The parathyroid gland responds to decreases in levels of extracellular calcium by increasing the secretion of both PTH and chromogranin-A (CGA) in approximately equal molar ratios. Because CGA has been suggested to be a precursor for biologically active peptides, we used primary cultures of bovine parathyroid cells to examine the effects of various peptides from CGA as well as analogous peptides from chromogranin-B (CGB) on PTH secretion. In concentrations from 10(-8)-10(-7) M, amino-terminal peptide CGA-(1-76) effectively inhibited the release of PTH in response to low extracellular calcium. Truncated analogs of this peptide, CGA-(1-40), CGB-(1-41), and CGA-(17-38) were also found to be active in the following order: CGA-(1-76) = CGA-(1-40) = CGB-(1-41) > CGA-(17-38). The biological activity of CGA-(1-40) was markedly reduced after reduction and alkylation, which resulted in disruption of the single disulfide bond between Cys17 and Cys38. Moreover, peptides derived from other regions of CGA and CGB, which included CGA-(403-428), CGB-(1-16), CGB-(316-326), and CGB-(635-657) were inactive. Pulse-chase experiments, using primary cultures of bovine parathyroid cells, revealed the presence of a CGA peptide in the culture medium that had the same amino-terminal sequence and mobility on sodium dodecyl sulfate-polyacrylamide gels as synthetic CGA-(1-76). Furthermore, in binding and cross-linking studies using intact parathyroid cells, CGA-(1-40) formed a single, covalently linked protein complex with a mol wt of 78,000. Formation of the protein complex could be completely inhibited in the presence of an excess of either CGB-(1-41) or CGA-(17-38). These results show that a naturally occurring amino-terminal peptide from CGA as well as shorter analogs can act as potent inhibitors of PTH secretion, and that their biological activity may be mediated through binding to a specific cell surface protein.

Animals↗
PubMed1994

A study of the relation between eating disorder and death concern.

The relationship between eating disorder and various components of death orientation (fear, anxiety, acceptance and concern) was examined, taking into account the level of depression in patient samples as well as elements of religiosity. The results were not able to support more than a very modest relationship between eating disorder and death orientation. Eating disorder patients could not be distinguished from other clinical controls, nor did anorexia nervosa patients differ from other eating disorder patients in this respect. Beck and Beck [20] depression scores were higher in the non eating disordered clinical sample than in the eating disorder group, and death concern was shown to be related to the severity of depression. Religiosity did not appear important when indices of religiosity were considered, but did emerge as an important factor in the "free information" provided by participants.

Adolescent↗
PubMed1994

Urinary enzymes as biomarkers of renal injury in experimental nephrotoxicity of immunosuppressive drugs.

Urinary excretion of N-acetyl-beta-D-glucosaminidase (NAG) and of alanine-aminopeptidase (AAP) was studied after administration of cyclosporine A (CSA A), FK 506, or the corresponding vehicles to salt-depleted rats. On days 7, 14, and 28 after treatment for CSA and day 14 after treatment for FK 506, measurements of the urinary enzymes, serum creatinine (SCr), creatinine clearance (ClCr), and blinded renal histology were done. After 1 week on CSA there was a dramatic increase of 489% in the urinary excretion of AAP (162.6 IU/g Cr, CSA vs. 27.6 IU/g Cr control, p < .03), a significant decrease of 32% in ClCr, a significant increase of 41% in SCr, and mild proximal tubular atrophy and vacuolization. After 2 or 4 weeks of CSA treatment there were no more differences in the urinary AAP between CSA and control rats, but the urinary excretion of NAG was increased: 29.6 IU/g Cr, CSA vs. 20.9 IU/g Cr, control, p < .03 on day 14 and 26.9 IU/g Cr, CSA vs. 21.5 IU/g Cr, control, p < .008 on day 28. At the same time there was a progressive decline of the ClCr, a progressive increase in the SCr, and an increase in the severity of the histological lesion. After 14 days of treatment with FK 506 we observed a striking elevation in urinary AAP (62.6 IU/g Cr, FK 506 vs. 36.0 IU/g Cr, control, p < .01) consistent with a significant decrease in ClCr, a significant increase in SCr, and a moderate proximal tubular vacuolization and atrophy.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylglucosaminidase↗
PubMed1994

Herpes simplex virus latency in tissue culture cells.

We have developed tissue culture systems which mimic certain aspects of herpes simplex virus (HSV) latency, in order to facilitate molecular studies of the phenomenon. The initial approach utilised incubation at 42 degrees C to suppress virus replication and establish stable latency after infection of human fibroblasts at low multiplicity with HSV-2. Latent virus was reactivated efficiently by superinfection of cultures with HSV-1 or human cytomegalovirus. Improvement of the system was achieved by use of the HSV-1 mutant in1814, which has a 12 base pair insertion in the coding sequences for the transactivating protein Vmw65 (VP16). Upon infection with in1814 at 42 degrees, or 37 degrees, it was possible to obtain cultures in which up to 21% of cells contained a viral genome. More recent modifications include the use of mutant in1820 (a derivative of in 1814) and pretreatment of cells with interferon alpha, which enable latency to be established in approximately 100% of cells. A system has therefore been developed that is suitable for the analysis of gene expression and genome structure during latency and reactivation.

Cells, Cultured↗
PubMed1993

Themes of death: Helmut Thomä's "Anorexia nervosa" (1967)--a research note.

In the recent literature on eating disorders, little attention is usually given to the possible role played by heightened death fears and anxieties and failed death transcendence in the dynamics of patients who suffer from anorexia and bulimia nervosa. For reasons that remain unclear, early texts and articles in the literature do address death themes, particularly as they are discernible from patients' dreams and nightmares. Thomä's 1967 text Anorexia Nervosa may be interpreted as giving further illustration to this thesis.

Adult↗
PubMed1993

Pneumatization of the uncinate process.

We report one case of extensive and two of partial pneumatization of the uncinate process from a consecutive series of 250 CT scans of the paranasal sinuses. The CT findings are illustrated and the literature reviewed.

Air↗