PubMed HealthSearch

Biomedical subjects

K Johnston

Publications and source records attributed to K Johnston.

At least 19 recordsLinked to original sources

The use of ECGs to record heart activity.

Most ECG recorders are single- or multi-channel. PC-based recorders are slowly evolving. Electrodes must be placed precisely to ensure accurate recording.

Arrhythmias, Cardiac

Valuing temporary and chronic health states associated with breast screening.

The aim of this study was to derive quality of life values for the four key breast screening outcomes (true negative, false positive, true positive and false negative), including the quality of life effects of the screening and treatment processes. In doing so, methodological issues in health status measurement were explored, in particular the valuation of temporary health states. The true negative and false positive descriptions were temporary health states, lasting for short term durations (12 months) and the true positive and false negative outcomes were chronic health states lasting for long term durations (rest of life). Descriptions of breast screening outcomes were valued using the time trade-off technique and the visual analogue scale. Paired comparisons between TTO values for states with the same duration found a difference between the true negative and the false positive time trade-off values but no difference for true positive and false negative descriptions. The TTO values for the false positive were low. The study highlights several important methodological issues such as the use of the two stage procedure for valuing temporary health states, the impact of duration on values, the impact of anchor points, and the importance of qualitative analysis of respondents values. Further empirical testing of all these issues is recommended.

Adult

Assessment of a new dipstick test in screening for microalbuminuria in patients with hypertension.

The prevalence of elevated urinary albumin levels is significantly greater in hypertensive than in normotensive subjects. To determine the sensitivity and specificity of a new dipstick test for microalbunimuria (the Micral-Test), 171 hypertensive patients were studied at a union-sponsored hypertension treatment program. Sensitivity, specificity, predictive values, and correlation coefficients between urinary albumin concentration results obtained by the Micral-Test and by nephelometry were determined in three urine samples. Sensitivity values of the Micral-Test, compared with 24-h nephelometry, were 81%, 75%, and 92% in a 24-h, overnight, and random sample, respectively. Specificity values were 89%, 90%, and 63% in the three samples, respectively. Positive predictive value ranged from 41% to 67%, whereas negative predictive value ranged from 93% to 97%. Correlation coefficients between the logarithms of albumin concentrations obtained from the three different urine specimens using nephelometry fell between 0.71 and 0.78, whereas those obtained with the Micral-Test fell between 0.49 and 0.71, and across techniques, 0.29 to 0.53 (all P < .001). Results obtained with both nephelometry and the Micral-Test using overnight and random urine collections approximated those obtained with 24-h collection. These results, coupled with the ease and convenience of both specimen collection and the Micral-Test itself, support the use of the test as a valuable screening tool for microalbuminuria in patients with hypertension.

Adult

Structures of SAP-1 bound to DNA targets from the E74 and c-fos promoters: insights into DNA sequence discrimination by Ets proteins.

SAP-1 is a member of the Ets transcription factors and cooperates with SRF protein to activate transcription of the c-fos protooncogene. The crystal structures of the conserved ETS domain of SAP-1 bound to DNA sequences from the E74 and c-fos promoters reveal that a set of conserved residues contact a GGA core DNA sequence. Discrimination for sequences outside this core is mediated by DNA contacts from conserved and nonconserved protein residues and sequence-dependent DNA structural properties characteristic of A-form DNA structure. Comparison with the related PU.1/DNA and GABPalpha/beta/DNA complexes provides general insights into DNA discrimination between Ets proteins. Modeling studies of a SAP-1/SRF/DNA complex suggest that SRF may modulate SAP-1 binding to DNA by interacting with its ETS domain.

Amino Acid Sequence

Electrolyte concentration differences between left and right vitreous humor samples.

Between-eye differences in electrolyte concentrations were studied in 200 medico-legal autopsies using an ion-specific electrode system. Taking the highest of the paired vitreous potassium concentrations, cases < 15 mM/L were classified as biochemically nonputrefied (Cat.1, n = 124), cases 15 to 20 mM/L as early putrefaction (Cat.2, n = 51), and cases > 20 mM/L as biochemically putrefied (Cat.3, n = 25). Mean paired vitreous sodium for all cases (n = 200) was 112 to 173 mM/L (mean 148, standard deviation (SD) = 8.9); between-eye differences were 0 to 8 mM/L (0% to 5.1% of mean), averaging 1.5 mM/L (1%) and with only one case (in Cat.3) outside instrument accuracy (+/- 3 mM/L). Mean paired vitreous chloride for all cases was 73 to 124 mM/L (mean 109, SD = 7.8); between-eye differences were 0 to 9 mM/L (0% to 8.8% of mean), averaging 1.7 mM/L (1.5%) and with 5 of 200 cases outside instrument accuracy (+/- 3 mM/L). Thus between-eye concentration differences of sodium and chloride are tolerable using this methodology. Previous reports of greater variability likely reflect errors introduced by sample manipulation prior to analysis. By contrast, between-eye differences in potassium in Cat.1 cases were 0 to 2.34 mM/L (0% to 21.8% of mean) averaging 0.37 mM/L (3.3%). Significant and erratic between-eye differences in potassium undermine the usefulness of vitreous potassium in estimation of time of death.

Electrolytes

Melatonin rescues dopamine neurons from cell death in tissue culture models of oxidative stress.

Dopamine (DA) neurons are uniquely vulnerable to damage and disease. Their loss in humans is associated with diseases of the aged, most notably, Parkinson's Disease (PD). There is now a great deal of evidence to suggest that the destruction of DA neurons in PD involves the accumulation of harmful oxygen free radicals. Since the antioxidant hormone, melatonin, is one of the most potent endogenous scavengers of these toxic radicals, we tested its ability to rescue DA neurons from damage/death in several laboratory models associated with oxidative stress. In the first model, cells were grown in low density on serum-free media. Under these conditions, nearly all cells died, presumably due to the lack of essential growth factors. Treatment with 250 microM melatonin rescued nearly all dying cells (100% tau+ neurons), including tyrosine hydroxylase immunopositive DA neurons, for at least 7 days following growth factor deprivation. This effect was dose and time dependent and was mimicked by other antioxidants such as 2-iodomelatonin and vitamin E. Similarly, in the second model of oxidative stress, 250 microM melatonn produced a near total recovery from the usual 50% loss of DA neurons caused by neurotoxic injury from 2.5 microM 1-methyl-4-phenylpyridine (MPP+). These results indicate that melatonin possesses the remarkable ability to rescue DA neurons from cell death in several experimental paradigms associated with oxidative stress.

Animals

Stability of hybridization activity of Coccidioides immitis in live and heat-killed frozen cultures tested by AccuProbe Coccidioides immitis culture identification test.

Frozen hyphal suspensions of Coccidioides immitis were evaluated for suitability as positive control cultures in the AccuProbe C. immitis culture identification test. The genetic probe hybridization activity of heat-killed and viable frozen cultures, stored at -20 and -70 degrees C and tested over a 10-month period, was compared to that of a freshly grown culture, and the results were evaluated based upon the manufacturer's established positive and negative photometric light unit (PLU) cutoff values. All C. immitis suspensions produced positive hybridization values well above the positive and negative cutoff values, and no significant decrease in hybridization activity was observed with the frozen cultures after 10 months of storage. The frozen, heat-killed suspensions produced PLU values with less variability (coefficient of variation, 8% over 10 months than the fresh or frozen viable cultures and were deemed the most stable and sale form of positive control material to use.

Coccidioides

UK breast screening programme: how does it reflect the Forrest recommendations?

OBJECTIVE: To compare the UK breast screening programme with the Forrest Report recommendations of 1986. SETTING: The UK breast screening programme. METHODS: A postal survey of 97 local breast screening programmes in the United Kingdom. The main outcome measures were the frequency of screening, the use of two view screening on incident screens, reading of screening mammograms, assessment procedures and visits, staffing levels, and the use of building and equipment. RESULTS: Eighty two (85%) of the questionnaires were completed and returned. All programmes screen every three years, as Forrest intended, with the exception of one health region which screens more often. The national policy is to use two views on incident screens where there is a clinical indication. None the less, 14% of programmes are using, or intending to use, two views on all women. Double reading of mammograms is not recommended in the United Kingdom outside Scotland, but is used by 88% of programmes. All programmes have access to the equipment required for the assessment techniques recommended by Forrest. Variation exists between programmes in the procedures women can expect to receive at their initial assessment visit and in the total number of assessment visits. Sixty eight per cent of programmes' breast screening budgets cover the staff required for a multidisciplinary team as defined by the Forrest Report. Ninety three per cent of screening programmes are organised around static sites, with 86% of these also using mobile vans. CONCLUSIONS: The national programme is following recommendations about the frequency of screening, but there seems to be some divergence from policy as regards the use of double reading, two views at incident screening, and the multidisciplinary team covered by the programmes' breast screening budget. Further research is needed on the effectiveness and cost effectiveness of two view incidence screening, double reading, and non-radiologists as readers. Investigation is also needed of the costs and effects of the variation between programmes in the number of assessment visits a woman may have.

Breast Neoplasms

Attitudes about skin cancer prevention: a qualitative study.

BACKGROUND: Skin cancer represents a significant threat to the health and well-being of Americans. By engaging in both primary and secondary preventive behaviors, individuals can reduce their risks of developing skin cancer. METHODS: Focus groups were used as a qualitative technique to explore the similarities and differences between those who practiced skin cancer prevention (a high-concern group) and those who did not (a low-concern group). Transcripts from the discussions were analyzed to identify themes regarding participants' attitudes, beliefs, and practices about skin cancer prevention. RESULTS: Seven themes emerged from the data: 1) benefits of sun exposure; 2) salience of skin cancer prevention; 3) perceived seriousness of the sun's harmful effects; 4) personal connection to skin cancer; 5) media attention regarding skin cancer; 6) problems with sunscreens; and 7) preventive health "have-tos." CONCLUSIONS: To improve skin cancer prevention, health education interventions must attend to individuals' attitudes about sun exposure and address the barriers related to them.

Adult

Hematologic emergencies in the intensive care unit.

Hematologic emergencies in the oncology population may require an admission to the intensive care unit (ICU). Syndrome of inappropriate antidiuretic hormone, hypercalcemia, tumor lysis syndrome, and disseminated intravascular coagulation are diseases defined in this article. These are common conditions in oncology patients that are reduced or prevented with close monitoring and accurate assessments. The purpose of this article is to introduce intensive care nurses to these disease entities so they will have a better understanding of the care involved with an oncology patient in the ICU unit.

Critical Care

An introduction to music therapy: helping the oncology patient in the ICU.

Oncology and critical care patients have unique and complex problems. With the explosion of technology and advances in medicine, many intensive care units are seeing an increase in oncology patients. Intensive care units are stressful and frightening; music therapy is a noninvasive holistic approach to bridging the gap between oncology patients and intensive care units.

Holistic Nursing

A new collaborative practice: critical care and hematology/oncology--altering the misconceptions.

For the two decades of development, intensive care units and hematology/oncology units have been separate entities, very territorial over their patient populations and precise in their expertise. The interactions between these units were minimal, and, therefore, many misconceptions have developed through the years. Some of these views have truth, and others are challengeable. A competitive rivalry has often developed between these two areas of expertise. However, with new technologies and therapies being investigated, these two units are interfacing to benefit patient care. Misconceptions can lead to fragmented care of the patient; poor communication between staff, units, patients and family members; and an increased stress level. The intent of this article is to define some of the most common misconceptions between these two disciplines and increase an understanding of each discipline's contribution to the well-being of the patient.

Attitude of Health Personnel

Two-year outcome of social skills training and group psychotherapy for outpatients with schizophrenia.

OBJECTIVE: The authors evaluated the effectiveness of behaviorally oriented social skills training and supportive group therapy for improving the social adjustment of schizophrenic patients living in the community and for protecting them against psychotic relapse. METHOD: Eighty male outpatients with schizophrenia were stabilized with a low dose of fluphenazine decanoate (5 to 10 mg every 14 days), which was supplemented with oral fluphenazine (5 mg twice daily) or a placebo when they first met criteria for a prodromal period. (Half of the patients did so at some time during the study.) Patients were randomly assigned to receive either social skills training or supportive group therapy twice weekly for 6 months and then weekly for the next 18 months. Rates of psychotic exacerbation were monitored, as were scores on the Social Adjustment Scale II. RESULTS: There were significant main effects favoring social skills training over supportive group therapy on two of the six Social Adjustment Scale II cluster totals examined (personal well-being and total) and significant interactions between psychosocial treatment and drug treatment for three items (external family, social and leisure activities, and total). In each case, these interactions indicated that the advantage of social skills training over supportive group therapy was greatest when it was combined with active drug supplementation. Social skills training did not significantly decrease the risk of psychotic exacerbation in the full group, but an advantage was observed (post hoc) among patients who received placebo supplementation. CONCLUSIONS: These findings suggest that social skills training resulted in greater improvement in certain measures of social adjustment than supportive group therapy. The greatest improvement in social outcomes occurred when social skills training was combined with a pharmacological strategy of active drug supplementation at the time prodromal worsening of psychotic symptoms was first observed. However, these improvements were modest in absolute terms and confined to certain subgroups of patients.

Adult

Experiences of battered women in health care settings: a qualitative study.

Interventions to help battered women seek and receive optimal health care must be informed by battered women's experiences in health care settings. In this study, we used a Systems Model to categorize the barriers battered women encounter in health care settings into patient, provider, and organizational levels. We conducted in-depth, face-to-face interviews with 31 battered women recruited by random digit dialing of households and by a publicity recruitment campaign. The data revealed that at the patient level, many women chose to conceal their abuse from their health care professionals, some fearing retaliation from their partners if they revealed the source of their injuries. At the provider level, the women perceived health care professionals to be disinterested or unsympathetic toward the needs of battered women, causing the women to feel ignored or trivialized. And at an organizational level, battered women believed that the structure of the health care system did not allow health care professionals enough time to deal with issues beyond treating their immediate presenting injuries. To ensure that battered women seek and receive optimal health care, multicomponent interventions should be designed to address the complex barriers at the three levels. We conclude by suggesting possible ways to help battered women get the tools they need to raise the issue of domestic violence with their health care professional. We also suggest ways to enable these professionals to identify battered women, validate their experiences, and provide appropriate referrals.

Adult