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Biomedical subjects

K Phillips

Publications and source records attributed to K Phillips.

At least 73 records · Page 4Linked to original sources
PubMed1997

Current practices regarding visitation policies in critical care units.

BACKGROUND: Previous research has emphasized the importance of visitation in critical care units and its beneficial effects on patients and their families. However, nurses' attitudes and beliefs about visitation did not correlate with those of patients and their families, nor did actual visitation practices correlate with written policy. OBJECTIVE: To investigate nurses' perceptions about open vs restricted visiting hours and the effects on the patient, the patient's family, and the nurse. METHODS: Quantitative and qualitative data were collected from 201 nurses who completed a survey instrument about nurses' perceptions of visitation at five metropolitan hospitals in a midwestern city. RESULTS: Seventy percent of official policies for visitation were restrictive. In practice, 78% of nurses were nonrestrictive in their visitation practices. Variables that affected practices regarding visiting hours were the patient's need for rest, the nurse's workload, and the beneficial effects of visitation on patients. Requests from patients and their families were ranked least important. Significant differences in practices were found regarding restriction of visiting by immediate family members and of the number of visitors. Restricted hours were perceived to decrease noise (83%) and promote patients' rest (85%). Open visitation practices were perceived to beneficially affect the patient (67%) and the patient's family (88%) and to decrease anxiety (64%). Perceptions of ideal visiting hours included restrictions on the number of visitors (75%), hours (57%), visits by children (55%), and duration of visits (54%), but no restriction on visitation by immediate family members (60%). Qualitative data revealed recurrent themes in visitation practices, policies and exceptions, control of visitation by patients, and nurses' wishes. CONCLUSION: Data indicate that most nurses do not restrict visitation, regardless of whether restrictive policies are in place. Most nurses base their visitation decisions on the needs of the patient and the nurse. Needs of the family were ranked as less important in decision making about family visitation.

Adult↗
PubMed1997

[Monitoring personal exposures to environmental air pollutants].

The fields of environmental epidemiology and analytical chemistry should work more closely together and with careful planning, could result in the two discrete disciplines complementing each other in a most positive way. Some of the methods for sampling air and its subsequent analysis have been described and analytical measurements have been compared with subjective assessments. Some real world exposure values for respirable suspended particles and environmental tobacco smoke in Hong Kong and Beijing have been contrasted with those for Barcelona in Europe. Time weighted average concentrations were discussed and cumulative frequency distributions compared between cities.

Air Pollutants↗
PubMed1996

The crystal structure of horse deoxyhaemoglobin trapped in the high-affinity (R) state.

Co-operative oxygen binding by the vertebrate haemoglobins arises from an equilibrium between a quaternary structure with low affinity (T), favoured in the absence of ligand, and a high affinity form (R) adopted by the fully ligated protein. While R state haemoglobin has an oxygen affinity close to that of isolated subunits, the affinity of the T state is roughly 300-fold lower. The mechanism by which the T state restrains ligand binding, and the pathway of the quaternary transition, have been largely revealed by detailed crystallographic analyses of a number of haemoglobin molecules in the equilibrium states, as well as intermediate forms of the T state including partially ligated species. The ligation intermediates of the R state, however, have not been as well characterized structurally. We report here the crystal structure of one such intermediate species, namely, horse deoxyhaemoglobin in the R state, at 1.8 A resolution. While ligand binding in the T state may result in unfavourable stereochemistry in and around the haem-ligand complex, the more plastic R structure appears to accommodate equally well both liganded and ligand-free haem. Loss of ligand at the R state haem results in movements of the haem and shifts of the FG corners, which form characteristic intersubunit contacts that distinguish the quaternary states. The shifts are comparable in magnitude to the corresponding movements associated with de-ligation in the T state, although they differ in direction. These and other differences illustrate how the structural changes in the haem pocket are communicated to the subunit interfaces and how the movements that can occur in the R state may be impeded in the T state.

Animals↗
PubMed1996

Effect of time of administration on the pharmacokinetics and tolerance of doxazosin in healthy male volunteers.

A randomized, open-label, two-way crossover study of 24 normotensive, healthy male volunteers with nocturia was conducted to compare morning and evening administration of doxazosin in terms of pharmacokinetics and tolerance. In both the morning and evening phases, participants received doxazosin 1 mg once daily for 10 days, followed by 2 mg once daily for 5 days. Pharmacokinetic data were evaluated from blood samples serially collected for 72 hours after drug administration on the last day of each phase. Vital signs and adverse events were recorded throughout the study. Mean peak plasma concentrations (C(max)) were 16.98 and 15.76 ng/mL after morning and evening administration, respectively. Corresponding mean values of area under the plasma concentration-time curve (AUC0-24) were 227.90 and 253.66 ng.hr/mL, respectively. Statistical analysis of the log-transformed values for C(max) and AUC0-24 indicated that morning and evening administration of doxazosin were bioequivalent. There were no statistically or clinically significant differences between phases for mean apparent half-life (t1/2) or total body clearance. There were no clinically relevant differences in blood pressure or in pulse rate between phases, and no occurrences of orthostatic hypotension. The incidence of adverse experiences during morning and evening administration was similar. Morning and evening administration of doxazosin are equivalent and have similar tolerance profiles.

Adrenergic alpha-Antagonists↗
PubMed1996

Identification of Tumor Suppressor Genes by Microcell Hybridization

Somatic cell genetic studies gave the first proof that functional tumor suppressor genes exist in mammalian genomes. Initial studies showed that whole-cell hybrids between tumorigenic mouse or human cell lines and their normal counterparts became nontumorigenic upon inoculation into animals. However, identification of the operative tumor suppressor gene proved difficult due to the presence of the entire chromosomal complement of the normal cell parent. The development of the technique of microcell hybridization has provided a powerful method for overcoming this obstacle. Suppression of transformed properties of a cancer cell line upon transfer of single human chromosomes from normal cells directly maps the location of tumor suppressor activity. One can then use positional cloning techniques or differential expression strategies to isolate the functional tumor suppressor gene. We present a general strategy for the mapping of tumor suppressor genes in mammalian cells. We also outline some of the important control experiments as well as pitfalls encountered in such studies.

Journal Article↗
PubMed1996

Moderating binge drinking: it is possible to change behaviour if you plan it in advance.

Recent theories of enactment suggest that behaviour change is increased by planning how, where, and when to execute a behavioural response. Drawing on these theories, a brief planning intervention was designed and its effectiveness compared to an information-based health promotion programme (control). All participants were given information about the safe limits per drinking occasion and the adverse consequences of binge drinking, and were asked to drink within the safe limits in order to avoid these consequences. In addition, participants in the planning group received an option menu of possible responses for refusing a drink, asked to choose one strategy and specify a time and place in which the chosen strategy would be implemented. The planning intervention group did not differ from the control group on reported likelihood of future binge drinking, nor on levels of past drinking, age and gender. At a 2-week follow-up, members of the planning intervention group reported lower drinking frequency than controls. The implications of prior planning for interventions aimed at reducing alcohol-related harm are discussed.

Adolescent↗
PubMed1996

Comparison of Periotest values of integrated implants with and without healing abutments: a pilot study.

The role of the Periotest in the clinical evaluation of osseointegration has been well documented. Some clinicians have used the initial Periotest values at second-stage surgery as a baseline to measure changes in integration at the bone-implant interface over time. The purpose of this pilot study was to compare Periotest values made with and without healing abutments in place. A statistically significant difference was found between the Periotest values that were recorded with and without healing abutments, with the values without the healing abutments being more negative and suggestive of greater osseointegration.

Dental Abutments↗
PubMed1996

The effect of epidural bupivacaine on the fetal electrocardiogram.

Fetal electrocardiogram waveform analysis was used to assess the effect of epidural bupivacaine on the fetal myocardial conducting system by evaluating its effect on the PR interval, RR interval, T/QRS ratio and the PR-RR correlation coefficient. There were no significant changes in either the PR interval or the PR-RR correlation coefficient. There was a significant increase in the fetal heart rate and a significant fall in the T/QRS ratio. Epidural bupivacaine does not alter fetal myocardial conduction as measured by the PR interval and it does not induce ischaemic cardiac changes as assessed by the T/QRS ratio.

Adolescent↗
PubMed1996

Assessment of air quality in Stockholm by personal monitoring of nonsmokers for respirable suspended particles and environmental tobacco smoke.

Exposure to respirable suspended particles (RSP) from all sources and environmental tobacco smoke (ETS) was assessed for 190 nonsmokers in Stockholm during 1994. Each subject wore a personal monitor for 24-h, provided saliva samples for cotinine analysis, and completed a detailed questionnaire about air quality and life-style. The subjects consisted of housewives and househusbands in one main group and working men and women in the second. The housewives and househusbands wore a single monitor throughout the 24-h period and the working subjects wore one monitor at work and a separate monitor while not at work. The geodemographic distribution of the recruited subjects accurately reflected the population of Stockholm. For most of the subjects, exposure to ETS and nicotine was at or below the limits of quantification (LOQ). This finding was supported by the fact that about 80% of the recruited subjects claimed that their exposure to ETS was "none" or "low". The concentration of RSP was found to be highest (median 39 micrograms.m-3) in homes where smoking occurred and below the LOQ in the workplace irrespective of its smoking status. These levels are at the lowest end of typical indoor air levels for RSP. For the housewives and househusbands living in smoking homes (nonsmoking homes in parentheses), the median exposure levels were 39 micrograms.m-3 (18 micrograms.m-3) for RSP, 17 micrograms . m-3 (0.12 micrograms . m-3) for ETS particles, and 1.1 micrograms.m-3 (0.05 micrograms.m-3) for nicotine. Both the pre- and postmonitoring continine saliva levels measured for these housewives and househusbands were 2.9 ng.ml-1 (pre-0.56 ng.ml-1, post-0.41 ng.ml-1). The highest exposure levels were recorded for the housewives and househusbands in the age range of 35-49 years. For the working subjects, the exposure measured in smoking workplaces (nonsmoking workplaces in parentheses) gave median levels of 16 micrograms.m-3 (16 micrograms.m-3) for RSP, 1.1 micrograms.m-3) for ETS particles and 0.2 micrograms.m-3 (0.15 microgram.m-3) for nicotine. Similarly measured exposures at home (nonsmoking homes in parentheses), including all other locations outside the workplace, gave median levels of 24 micrograms.m-3 (19 micrograms.m-3) for RSP, 1.4 micrograms. m-3 (0.2 microgram.m-3) for ETS particles, and 0.15 microgram.m-3 (0.07 microgram.m-3) for nicotine. Overall, the exposure levels of ETS due to living with smokers in Stockholm was found to be much lower than similar exposures measured previously in the United Kingdom and the United States. Over 70% of all the nicotine measurements and 60% of all the ETS measurements were below the LOQ. When the median values for nicotine and ETS particles are converted to cigarette equivalents, Stockholm housewives and househusbands living with smokers would receive 6-9 cigarette equivalents per year, working nonsmokers living with smokers would receive 0.6-0.7 cigarette equivalents at home, and nonsmokers working with smokers would be exposed to 0.1-0.2 cigarette equivalent at work. The exposures were therefore up to six times greater at home than in workplaces where smoking was occurring. Although all the subjects were recruited as nonsmokers on the basis of their self-reported nonsmoking status, saliva continine measurements were used for confirmation. Subjects with continine levels below 25 ng.ml-1 were considered to be nonsmokers although the selection of a threshold level within the range of 10-50 ng.ml-1 was not considered to be critical. With a threshold of 25 ng.ml-1, between 2.7% and 5.3% were later shown to be misclassified as nonsmokers, depending on the definition of misclassification used. During the study period the air quality in Stockholm could be described according a British nomenclature as "very good" for the majority of the time. The daily average at no time fell below "good," and the maximum hourly nitrogen dioxide level was 111 micrograms.m-3 (inner city at street level) on the coldest day

Adult↗
PubMed1996

High-efficiency retroviral vector mediated gene transfer into human peripheral blood CD4+ T lymphocytes.

Genetic modification of peripheral blood T lymphocytes has been proposed as a therapeutic strategy for treating congenital disorders, cancer and viral diseases. Central to all T lymphocyte-based gene therapy strategies is the ability to efficiently and stably deliver genes into primary T lymphocytes. In this study, we sought to increase the gene transfer efficiency in CD4+ peripheral blood T lymphocytes using procedures which could be utilized in clinical applications. In order to quantity the gene transfer efficiency in primary CD4+ T cells, a high-titer retroviral vector which efficiently expresses a truncated version of the human low-affinity nerve growth factor receptor (delta LNGFR) was constructed. Transduced cells were then accurately enumerated with immunofluorescence staining and fluorescence activated cell sorting (FACS) analysis and rapidly isolated at high purity for further analysis. Using this system, a supernatant-based gene transfer procedure was developed which routinely yields gene transfer efficiencies of 25-40% into a wide repertoire of both freshly obtained and cryopreserved peripheral blood CD4+ T lymphocytes.

3T3 Cells↗
PubMed1995

Randomized clinical trial of antithymocyte globulin induction in renal transplantation comparing a fixed daily dose with dose adjustment according to T cell monitoring.

Antithymocyte globulin (ATG) has been used successfully for induction therapy as well as for treatment of established allograft rejection. However, this therapy has often been associated with problems of overimmunosuppression and increased costs. In a randomized clinical trial, we compared the immunosuppressive benefits, complication rates, and treatment costs when ATG is given as a fixed daily dose or when the dose is adjusted daily according to its biologic effects on T cells. Forty-five recipients of cadaver renal allografts were randomized into two groups. In group 1 (n = 23), ATG (ATGAM) was administered in variable doses to maintain the absolute number of peripheral CD3 T cells at 50-100/microliters. In group 2 (n = 22), ATG was given at a fixed dose of 15 mg/kg/day. All patients received azathioprine and prednisone. ATG was discontinued at 7-14 days when cyclosporine was introduced. In both groups, CD2, CD3, CD4, CD8, and CD19 cells were measured by flow cytometry and the levels of cytokines IL-1 beta, IL-2R, ICAM-1, IL-6, IL-7, and levels of cytokines IL-1 beta, IL-2R, ICAM-1, IL-6, IL-7, and levels of cytokines IL-1 beta, IL-2R, ICAM-1, IL-6, Il-7, and IL-10 were measured by ELISA. In group 2, the levels of all T cell subsets were profoundly suppressed. In group 1, the number of CD3 and other T cells was maintained at about 100 cells/microliters, while the CD19 T cells remained unsuppressed. Cytokine levels were greatly suppressed in group 2 compared with group 1, except for IL-10 levels, which remained elevated in the latter group. Patient survival, graft function, and the incidence of acute and recurrent rejections were similar in the two groups. Bone marrow suppression and infective complications were greater in group 2 than in group 1. The mean daily dose and the total quantity of ATG used in group 1 were significantly smaller than in group 2, resulting in a savings of $2,398.00 per patient per treatment. It is concluded that monitoring of ATG by its biologic effects on T cells is a rational and safe method of regulating the dose of this important agent; in this way, it is possible to reduce the total amount of the drug given to patients with consequent reduction in undesirable complications as well as in the cost of treatment without loss of immunosuppressive benefits.

Adult↗
PubMed1995

Quantitative genetic analysis of injury liability in infants and toddlers.

A threshold model of latent liability was applied to infant and toddler twin data on total count of injuries sustained during the interval from birth to 36 months of age. A quantitative genetic analysis of estimated twin correlations in injury liability indicated strong genetic dominance effects, but no additive genetic variance was detected. Because interpretations involving overdominance have little research support, the results may be due to low order epistasis or other interaction effects. Boys had more injuries than girls, but this effect was found only for groups whose parents were prompted and questioned in detail about their children's injuries. Activity and impulsivity are two behavioral predictors of childhood injury, and the results are discussed in relation to animal research on infant and adult activity levels, and impulsivity in adult humans. Genetic epidemiological approaches to childhood injury should aid in targeting higher risk children for preventive intervention.

Adult↗