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Biomedical subjects

M Keen

Publications and source records attributed to M Keen.

At least 19 recordsLinked to original sources
PubMed2000

Effective preexposure tuberculosis vaccines fail to protect when they are given in an immunotherapeutic mode.

Two vaccine formulations previously shown to induce protective immunity in mice and prevention of long-term necrosis in guinea pigs were tested as potential immunotherapeutic vaccines in mice earlier infected by aerosol with Mycobacterium tuberculosis. Neither vaccine had any effect on the course of the infection in the lungs, but both reduced the bacterial load in the spleen. Similarly, inoculation with Mycobacterium bovis BCG had no effect whatsoever and, if given more than once, appeared to induce an increasingly severe pyogranulomatous response in the lungs of these mice.

Animals↗
PubMed1998

Nursing assessment and intervention for adult hemodialysis patients: application of Roy's Adaptation Model.

A comprehensive assessment tool and intervention typology for adult hemodialysis patients, based on the Roy Adaptation Model, is presented. The Roy model is reviewed, and examples from the assessment tool and intervention typology are presented. A case study illustrates application of the tool and typology to nephrology nursing. Comparison of the tool and typology with the ANNA Standards of Clinical Practice revealed that the Roy Adaptation Model includes additional important aspects of nephrology nursing practice.

Adaptation, Physiological↗
PubMed1997

Expression of memory immunity in the lung following re-exposure to Mycobacterium tuberculosis.

OBJECTIVE: To examine the memory immunity expressed in the lung in response to a low-dose aerosol challenge. DESIGN: Memory-immune C57BL/6 mice were generated by infection followed by drug treatment with isoniazid and rifabutin. Both memory-immune and naive mice were then rechallenged via both the aerosol and intravenous routes. The growth of bacteria in target organs, the expression of cytokines within these organs and the ability of T cells to recognize selected mycobacterial protein antigens were determined over time. RESULTS: There was a finite delay before immunity was expressed in the lungs of the memory-immune mice. This was in contrast to the immediate control of bacterial growth seen in the liver of intravenously challenged mice. In both cases, the expression of interferon-gamma (IFN-gamma) mRNA in the target organ correlated with the control of bacterial growth. Memory immunity in the spleen and lung differed: whereas splenic T cells strongly recognized the major Ag85 protein, the 45 kDa protein, and a synthetic peptide representing the ESAT molecule, only the Ag85 molecule was recognized by T cells harvested from thoracic lymph nodes after pulmonary rechallenge. CONCLUSIONS: Immunity, as mediated by IFN-gamma, is expressed more slowly following an aerosol rechallenge and appears to be restricted in terms of antigen specificity. Moreover, very strong levels of memory immunity can prevent progressive disease in the lungs, but cannot prevent the establishment of secondary infection.

Animals↗
PubMed1997

Long-term clinical results and quality of life after insertion of a self-expanding flexible endourethral prosthesis.

OBJECTIVE: To evaluate the safety and efficacy of the Urolume self-expanding flexible endourethral stent, based on a long-term follow-up, and to determine its role amongst the various modalities of treatment available for the relief of bladder outlet obstruction (BOO) arising from benign prostatic hyperplasia (BPH). PATIENTS AND METHODS: From January 1991 to April 1992, the Urolume wallstent (American Medical Systems, USA) was placed successfully in each of 62 patients (aged 50-89 years) who had significant subjective and objective evidence of BOO. The stent was placed as a daycase procedure under general anaesthesia. Pre-operatively, each patient was assessed fully in an out-patient clinic by symptoms, a flow rate measurement and a rectal examination. Post-operatively, patients were assessed using transrectal ultrasonography, cystoscopy, symptoms and flow rate measurement, and after 5 years, the International Prostate Symptom Score and satisfaction score were obtained. RESULTS: After 5 years, 27 (39%) patients survived and 10 (14%) died with their Urolume stent intact; 22 (32%) completed the follow-up and five refused or were lost to follow-up. Day and night-time frequencies and flow rates improved continuously. Complete epithelialization occurred in 16 of the 22 patients assessed. Of those in whom the Urolume was removed, 20 are alive and five dead. CONCLUSION: The effectiveness of the Urolume in improving symptoms and flow rates in patients with BPH was confirmed. However, the high failure rate arose largely from inexperience in selection and deployment. There are no absolute criteria to predict a successful outcome. This study confirms the Urolume as a safe device. Most patients whose symptoms settled in the first year maintained a good flow rate and a significant improvement in symptoms for 5 years; their quality of life at the last follow-up was good.

Aged↗
PubMed1997

Quantitative magnetic resonance imaging of the knee: a method of measuring response to intra-articular treatments.

OBJECTIVES: To investigate the potential of quantitative magnetic resonance imaging (MRI) to differentiate between therapeutically induced changes in inflammation and synovial proliferation in rheumatoid arthritis (RA) of the knee. METHODS: MRI of the knee was performed on patients with RA before and one week after injection with corticosteroid (triamcinolone acetonide, TA group, n = 9) and before, four, and 12 weeks after injection with yttrium-90 plus TA (TA+Y group, n = 7). MRI scans were analysed by subjective visual grading by a trained observer and by computer aided quantitation for three features: synovial fluid volume, synovial pannus volume, and synovial enhancement after intravenous contrast agent. RESULTS: All TA subjects improved clinically at one week but the effects of TA+Y were more variable. TA significantly reduced synovial enhancement and effusion volume, whereas TA+Y at 12 weeks tended to increase synovial enhancement and decrease pannus volume. Quantitative MRI values agreed well with subjective assessment of scans. Comparison of calculated change on MRI scan before and immediately after aspiration with actual volume aspirated showed high correlation (r = 0.96). CONCLUSIONS: Quantitative MRI correlates with subjective visual assessment and, at least for synovial fluid, is accurate. MRI can differentiate actions of two therapeutic modalities on various pathological processes and is sensitive enough to detect change after one week. With the additional advantage of lack of observer bias, it will probably become a useful tool in the development and assessment of existing and novel treatments.

Adult↗
PubMed1996

Renal regulation of extracellular fluid volume and osmolality.

In order for our body cells to function properly, they must be surrounded in extracellular fluid that is relatively constant with regard to osmolality. The kidneys, in concert with neural and endocrine input, regulate the volume and osmolality of the extracellular fluid by altering the amount of sodium and water excreted. This is accomplished primarily though alterations in sodium and water reabsorption, the mechanisms of which differ within each nephron segment.

Chlorides↗
PubMed1995

Inhibition of prostacyclin release from cultured endothelial cells by nitrovasodilator drugs.

Pretreatment (18 h) of the bovine aortic endothelial cell line AG4762 to 500 microM sodium nitroprusside (SNP), glyceryl trinitrate (GTN) or 3-morpholino-sydnonimine (SIN-1) significantly inhibited 100 nM bradykinin-stimulated prostacyclin (PGI2) release. SIN-1 produced the greatest reduction (67 +/- 6%), followed by SNP (47 +/- 12%) and GTN (45 +/- 9%). Only SIN-1 and GTN inhibited basal PGI2 release where again the effect of SIN-1 (66 +/- 6%) was greater than that of GTN (31 +/- 15%). There was no effect of SNP on basal PGI2 release. We have demonstrated this inhibition of bradykinin-stimulated PGI2 release is not the result of cell death. In addition, 8-bromo-cyclic GMP, whilst having no effect on basal PGI2 release, demonstrated a small but significant inhibition (15 +/- 6%) of the enhanced response to 100 nM bradykinin. These studies may reflect a mechanism by which the release of vasodilators from endothelial cells is altered during therapy with nitrovasodilators and thus may contribute to the development of tolerance to these drugs.

Adenosine Triphosphate↗
PubMed1995

Current standards for dialysis adequacy.

Multiple lines of evidence suggest that inadequately prescribed or delivered dosage of hemodialysis is associated with increased morbidity and mortality. Conversely, retrospective studies indicate that increased levels of hemodialysis reverse this trend of poor outcome. The results of the National Cooperative Dialysis Study (NCDS), a prospective and randomized trial, suggested that urea kinetic modeling was a valid method of quantifying the dose of hemodialysis delivered and also identified a level of treatment below which a number of adverse events occurred. In the ensuing years, urea kinetic modeling has been increasingly applied to quantitate dialysis. The application of the NCDS results as well as the limitations of the study are reviewed, and the modifications in applying urea kinetic modeling due to urea rebound are discussed. To assess the impact of newer membranes and higher levels of dialysis on an older hemodialysis population with more comorbid conditions than the subjects studied in the NCDS, a 5-year, multicenter, prospective and randomized trial, the HEMO Study, has recently been initiated.

Evaluation Studies as Topic↗
PubMed1995

Nurse's role in achieving patient outcomes.

Nephrology nursing's influence on patient outcomes has as many facets as there are practice roles in nephrology nursing. These speakers discussed the impact on patient outcomes from a variety of practice perspectives. The roles of administrator, educator, staff nurse, government nurse, research nurse, and corporate nurse are each described.

Humans↗
PubMed1994

The role of protein kinase A and protein kinase C in prostanoid IP receptor desensitization in NG108-15 cells.

Pretreatment of NG108-15 cells for 1 h with 1 microM phorbol 12-myristate,13-acetate produced no significant effect on the subsequent stimulation of adenylate cyclase activity by the IP receptor agonist, iloprost, the adenosine A2 receptor agonist, N-ethylcarboxamidoadenosine (NECA), or sodium fluoride, suggesting that protein kinase C activation does not produce desensitization in this system. Pretreatment of cells with 10 microM iloprost or forskolin for 17 h produced a decrease in the specific binding of [3H]iloprost, consistent with a decrease in IP receptor number. Iloprost pretreatment produced a decrease in responses to iloprost, NECA and sodium fluoride, whereas forskolin pretreatment produced a decrease in subsequent responsiveness to iloprost and NECA, but the response to sodium fluoride remained unaffected. The desensitization produced by forskolin could be completely inhibited by the inhibitor of protein kinase A and protein kinase C, 1-(5-isoquinolinylsulfonyl)-2-methylpiperazine (H7), but H7 had no effect on the desensitization produced by iloprost.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗