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Biomedical subjects

L Clarke

Publications and source records attributed to L Clarke.

At least 109 records · Page 6Linked to original sources
PubMed1996

The last post? Defending nursing against the postmodernist maze.

Is postmodernism in many ways the empiricist-liberal tradition at the inevitable end of its intellectual and political tether? Or is postmodernism the 'laughter of genius' that art and argument in their traditional forms are dead? Can postmodernism be applied to social and economic issues whilst carrying a denial of the manner by which Western thought has shaped these issues? Can postmodernism provide moral pathways to help us with contemporary ethical issues? How can postmodernist thought encompass the activities of nurses, particularly in the area of psychiatric care? Can nurses afford postmodernist suppositions in the face of suffering and pain? If postmodernism exists, does it exist everywhere (as does nursing) or is it a more localized event?

Attitude to Health↗
PubMed1996

Influence of rearing temperature on lung development following methimazole treatment of postnatal lambs.

This study examines the effect of ambient temperature on lung development over the first month of postnatal life in lambs treated with a drug which inhibits thyroid hormone synthesis (methimazole, 50 mg day-1 (kg body wt-1)). Twin lambs were hand-reared at a fixed level of nutrition in either a warm (WR, 25 degrees C) or cool (CR, 10-15 degrees C) ambient temperature. Plasma thyroid hormone concentrations were significantly (P < 0.05) lower in WR lambs, but there were no differences between WR and CR groups in thyroid gland weight or hepatic iodothyronine 5'-deiodinase activity at 8 or 29 days of age. Lung weights and the ratio of lung weight to O2 consumption were similar in WR and CR groups at 8 days but both were significantly lower (P < 0.01) in CR lambs at 29 days. Lung weight at 29 days was significantly (P = 0.002) correlated with plasma triiodothyronine concentration in CR but not WR lambs, and laryngeal braking of expiratory airflow was observed in three of seven CR lambs but not in WR lambs. Four WR, but no CR, lambs exhibited a rapid deterioration in health or died unexpectedly between 14 and 21 days of age. These WR lambs were characterized by having small lungs and slower growth rates. It is concluded that in WR lambs chronically treated with methimazole, both lung development and the ability of an individual to adapt effectively to methimazole treatment are compromised. In CR lambs, although lung growth may be reduced this does not appear to compromise O2 consumption or health.

Animals↗
PubMed1996

Effect of rearing temperature on perirenal adipose tissue development and thermoregulation following methimazole treatment of postnatal lambs.

This study examined the effect of ambient temperature on perirenal adipose tissue development and thermoregulation over the first month of postnatal life in lambs treated with a drug that reduces thyroid hormone synthesis (methimazole; at a dose of 50 mg day-1 (kg body weight)-1). Twin lambs were hand-reared at a fixed level of nutrition in either a warm (WR; 25 degrees C) or cool (CR; 10-15 degrees C) ambient temperature. Oxygen consumption, heart rate and colonic temperature were measured during non-rapid eye movement sleep in different ambient temperatures (6, 15, 25 and 34-36 degrees C) at 7, 14 and 28 days of age. Plasma thyroid hormone concentrations decreased with postnatal age and were higher in CR than in WR lambs. All lambs increased plasma thyroid hormone concentrations and O2 consumption during cold exposure but this was associated with a mean increase in colonic temperature in WR lambs at 7 or 28 days. Colonic temperature increased with the onset of panting at all ages when lambs were exposed to 34-36 degrees C, a response that was greatest at 28 days in CR lambs. An increase in colonic temperature with age was observed in CR but not WR lambs. Heart rate declined with age only in the WR group. At 8 and 29 days there were no significant differences between WR and CR groups in the occurrence of shivering or in the thermogenic activity (i.e. GDP binding to mitochondria) of perirenal adipose tissue. At 29 days WR lambs possessed more adipose tissue with a higher lipid and DNA content. It is concluded that modest changes in rearing temperature can have a large influence on the control of body temperature and thyroid hormone response to methimazole treatment. CR lambs are able to maintain higher plasma thyroid hormone concentrations and exhibit improved thermoregulation compared with WR lambs without any detectable differences in brown adipose tissue function.

Adipose Tissue↗
PubMed1996

Effect of beta 3-adrenergic agonist (Zeneca D7114) on thermoregulation in near-term lambs delivered by cesarean section.

We investigated the effect of a beta 3-adrenergic agonist, Zeneca D7114, on thermoregulation in near-term lambs delivered by cesarean section. Lambs were delivered into a cool ambient temperature of 15 degrees C, and between 60 and 80 min of life were given an oral dose of Zeneca D7114 (10 mg.kg body weight-1) dissolved in 20 mL of milk, or milk alone. During the first 0.5 h of life colonic temperature decreased in all lambs, and then increased to plateau levels (39.6-40.4 degrees C) after 120-150 min of life, in 19 out of 23 lambs studied. In the remaining lambs, colonic temperature failed to return to normothermic values, plateauing at 34.3 degrees C. All control lambs were observed to shiver throughout the study, but after Zeneca D7114 treatment 7 out of 10 normothermic lambs stopped shivering, and plateau colonic temperature was 0.8 degree C higher. Hypothermic beta 3-agonist-treated lambs had significantly lower rates of heat production, breathing frequency, and plasma triiodothyronine and cortisol concentrations than normothermic lambs. the level of GDP binding and norepinephrine content of brown adipose tissue (BAT) sampled from hypothermic beta 3-agonist-treated lambs was significantly lower than in normothermic lambs. There was no difference in GDP binding in BAT between control and Zeneca D7114-treated groups, but the Hb content was higher in the latter group. It is concluded that administration of Zeneca D7114 to euthyroid lambs enhances their ability to thermoregulate and restore colonic temperature without altering the thermogenic activity of BAT. This response may be mediated by increasing blood flow to BAT and/or an improvement in the animal's thermal efficiency (i.e. decreased heat loss) due to a reduced reliance on shivering thermogenesis.

Adaptation, Physiological↗
PubMed1996

Selective blockade of cholecystokinin type B receptors with L-365,260 does not impair gallbladder contraction in normal humans.

OBJECTIVES: To evaluate the effect of selective blockade of type B cholecystokinin receptors on gall bladder contraction in normal humans and to compare methods for quantitative analysis of gall bladder contraction. METHODS: L-365,260, a novel, nonpeptide cholecystokinin antagonist shown to be selective for type B cholecystokinin receptors, was administered every 6 h over a 5-7 day period. Plasma levels of L-365,260 were determined by high pressure liquid chromatography. Gallbladder contraction after a standardized fatty meal was measured by ultrasonography, and results were calculated by ellipsoid or sum of cylinders methods. RESULTS: L-365,260 levels were comparable to levels in earlier studies demonstrating inhibition of pentagastrin-stimulated acid secretion in normal subjects and blockade of anxiogenic effects of cholecystokinin injections in patients with panic disorder. Regardless of the method used for estimating gallbladder size, none of the L-365,260 doses studied inhibited gallbladder contraction. Gallbladder size was most consistently estimated by the ellipsoid method using measurements normalized to individual values for minimum and maximum gallbladder dimensions. CONCLUSIONS: Multiple oral doses of L-365,260 do not alter ultrasonographically assessed gallbladder contraction at doses shown to be clinically effective in earlier studies. Despite being more difficult to implement, the sum of cylinders method for estimating gall bladder size offers no advantage over the ellipsoid method.

Adult↗
PubMed1996

Recombinant human interleukin-3 (rhIL-3) enhances the mobilization of peripheral blood progenitor cells by recombinant human granulocyte colony-stimulating factor (rhG-CSF) in normal volunteers.

To identify a precisely timed and safe protocol for progenitor cell mobilization, we studied the effects of rhIL-3 and rhG-CSF administration to normal volunteers. rhG-CSF 5 micrograms/kg/d was administered subcutaneously (s.c.) for 7 consecutive days either alone or preceded by rhIL-3 5 micrograms/kg/d s.c. for 4 consecutive days in sequential or partially overlapping schedules. The combined cytokines were well-tolerated--adverse effects were similar to those of the individual agents. Total white blood cell (WBC) and neutrophil counts rose briskly in response to rhG-CSF, and peak mean values were similar between treatment cohorts. Mean platelet counts were modestly elevated during rhG-CSF treatment only in the cohorts receiving rhIL-3 and rhG-CSF. Mean circulating CD34+ cells peaked on day 5 in the rhG-CSF group (38.9+/-14.3/microliter), day 6 in the sequential rhIL-3/rhG-CSF group (56.4+/-12.4/microliter), and day 6 in the partial overlap group (46.1+/-10.9/microliter). On day 3, mean CD34+ cell counts of the subjects who received sequential treatment were markedly higher than observed in the other groups (p<0.05) and were estimated to have been sufficient for collection of adequate grafts by single 10-L leukapheresis procedures in 60% of subjects. Circulating clonogenic cells (CFU-GM and/or BFU-E) were substantially higher in the sequential group than the rhG-CSF group on days 3-6 but were only minimally elevated above baseline in the partial overlap group. The numbers of circulating CD34+/Lin-/Thy-1+ cells (putative stem cells) were increased substantially, especially in the sequential group. On the basis of this pilot trial, we conclude that priming with rhIL-3 is a safe and well-tolerated method for enhancing the mobilization of human blood progenitors and stem cells by rhG-CSF.

Adult↗
PubMed1996

Dispersal of 10-14-mesh corncob granules in stacked tires.

Dispersal of 10-14-mesh corncob granules was evaluated in 2 random-stacked tire piles, one shingle-stacked tire pile, and one column-stacked tire pile located in a used-tire storage facility in Chicago, IL. Ninety percent and 98%, respectively, of the tires in the 2 random-stacked piles contained granules. In the shingle-stacked tire pile 87% of the tires sampled contained granules, and the number of granules per tire was dependent on depth. The 2 bottom rows of tires were 73.9% less likely to contain granules than the 5 rows above them. In the column-stacked tire pile 91.2% of the tires contained granules and the relationship between granule recovery and tire depth was logarithmic. Overall, the dispersal of 10-14-mesh corncob granules was comparable to that of 8-mesh corncob granules evaluated in a previous study at this site.

Mosquito Control↗
PubMed1996

Anxiety in patients with symptomatic breast disease: effects of immediate versus delayed communication of results.

Immediate reporting of fine needle aspiration biopsy (FNAB) specimens has been introduced into many breast clinics; in others, women return to a later clinic to receive the result. This delay in communication of results may lead to elevated anxiety. This study compared anxiety levels in two groups having FNAB. One group received results at the initial clinic visit (n = 51), the other having delayed communication (n = 51). Anxiety was measured using the six-item short form of the Spielberger State-Trait Anxiety Inventory (STAI-SSF) and was administered before and after each consultation. Initial anxiety was high in both groups. Women with malignant results had higher post-communication anxiety compared with women with benign results. However, within the group with benign results (the vast majority), immediate communication was associated with a significantly greater fall in STAI-SSF scores from before to after the first consultation (U = 587.0; P < 0.02). There was no difference between the immediate and delayed communication among women with a malignant diagnosis (U = 26.0; P = 0.91). These results provide preliminary support for the more widespread introduction of a cytologist into breast clinics to allow immediate communication of results.

Anxiety↗
PubMed1995

Increased genital shedding of herpes simplex virus type 2 in HIV-seropositive women.

OBJECTIVE: To compare the prevalence of genital herpes simplex virus type 2 (HSV-2) shedding in human immunodeficiency virus (HIV)-seropositive women and HIV-seronegative women. DESIGN: Cross-sectional study. SETTING: A major inner-city medical center. PATIENTS: 106 women who were HIV-seropositive and HSV-2-seropositive and 70 women who were HIV-seronegative and HSV-2-seropositive were enrolled from various primary care settings. MEASUREMENTS: Herpes simplex virus type 2 antibody determinations were done for all patients. Regardless of symptoms, vulvar and cervical HSV cultures were obtained from all HIV-seropositive women and from a randomly selected subgroup of HIV-seronegative women. RESULTS: The prevalence of HSV-2 shedding was nearly four times greater in HIV-seropositive than in HIV-seronegative women (13.2% compared with 3.6%; P = 0.04; odds ratio, 4.1 [95% CI, 1.0 to 27.4]) when the serum antibody for HSV-2 was present. Seventy-nine percent of viral shedding among HIV-seropositive women was asymptomatic. Overall viral shedding increased significantly as the CD4 cell count decreased. CONCLUSIONS: Women with HIV infection, particularly those with low CD4 cell counts, shed HSV-2 from the vulva and cervix more commonly than women not infected with HIV. Most of this shedding is asymptomatic.

CD4 Lymphocyte Count↗
PubMed1995

Pharmacodynamics of daily subcutaneous recombinant human interleukin-3 in normal volunteers.

Normal volunteers received subcutaneous injections of recombinant human interleukin-3 (rhIL-3) on 4 consecutive days to characterize toxicity, pharmacokinetics, and hematopoietic effects. Dosages were 2.5, 5.0, and 7.5 micrograms/kg/day (n = 6 subjects per group). Adverse effects consisted predominantly of flu-like symptoms such as fever and headache. Mean area under the serum concentration-time curve and maximum serum concentration were linearly related to dose. Serum clearance was not apparently related to dose. Clearance increased slightly but significantly between days 1 and 4. Rapid but modest elevations in neutrophil and eosinophil counts were observed during treatment. Mean platelet counts rose modestly, peaking on day 10. Increases of CD34+ cell counts were correlated with increases of colony-forming unit-granulocyte macrophage (peak, day 7).

Adult↗
PubMed1995

A novel cis-acting centromeric DNA element affects S. pombe centromeric chromatin structure at a distance.

The chromatin structure of the central core region of Schizosaccharomyces pombe centromeric DNA is unusual. This distinctive chromatin structure is associated only with central core sequences in a functional context and is modulated by a novel cis-acting DNA element (centromere enhancer) within the functionally critical K centromeric repeat, which is found in multiple copies in all three S. pombe centromeres. The centromere enhancer alters central core chromatin structure from a distance and in an orientation-independent manner without altering the nucleosomal packaging of sequences between the enhancer and the central core. These findings suggest a functionally relevant structural interaction between the enhancer and the centromeric central core brought about by DNA looping.

Blotting, Southern↗
PubMed1995

Nursing research: science, visions and telling stories.

Some aspects of qualitative and quantitative approaches to nursing research are described, with particular emphasis on the critical assessment of the qualitative approach. While common objections to quantitative (statistical) studies are mentioned, the main thrust is against the lack of generalizability of much contemporary qualitative work. Concepts of validity and reliability are additionally scrutinized in the context of their use by ethnographers. Grounded theory is a primary focus since it harbours most of the departures--and terminology--of the non-quantitative schools. It is surmised that much of what passes as qualitative research is really a creative activity akin to the writing of the poem or novel.

Nursing Methodology Research↗
PubMed1995

Environmental effects on thermoregulation and breathing patterns during early postnatal development in hand-reared lambs.

This study examines the effect of hand-rearing developing lambs in a warm (WR; 25 degrees C) or cool (CR; 10-15 degrees C) ambient temperature on the control of thermoregulation and breathing patterns, when maintained at a fixed level of nutrition over the first month of postnatal life. Measurements were made during non-rapid eye movement sleep whilst lambs were maintained for at least 1 h at warm (28-19 degrees C) and cold (14-5 degrees C) ambient temperatures at 1, 7, 14 and 30 days of age. All lambs were able to maintain normal body temperature, but oxygen consumption was higher in CR lambs at 14 and 30 days of age. At 1 day of age shivering was rarely observed in any lambs, but at 7 and 14 days of age more WR than CR lambs responded to cold exposure via shivering. Plasma concentrations of triiodothyronine were higher at 7 and 14 days of age in CR lambs. Breathing frequencies were similar in WR and CR lambs, and from 7 days of age the incidence of expiratory laryngeal braking was higher in warm compared with cold study temperatures. By 30 days of age the recruitment of this mechanism was greater in CR lambs. Mean growth rate was slower over the first week of postnatal life in CR compared with WR lambs. This difference decreased over the first month of life, as growth rate increased from 83 to 130 g day-1 in the CR group but remained constant at approximately 150 g day-1 in the WR lambs. Total weight of the lungs and heart, but not the liver, were lower at 1 month but not at 1 week of postnatal life in CR lambs. It is concluded that a modest decrease in the ambient temperature in which postnatal lambs are reared, when on a fixed feed intake, alters lung size, the recruitment of laryngeal braking and the control of body temperature.

Animals↗
PubMed1995

Replication of centromere II of Schizosaccharomyces pombe.

The centromeric DNAs of Schizosaccharomyces pombe chromosomes resemble those of higher eukaryotes in being large and composed predominantly of repeated sequences. To begin a detailed analysis of the mode of replication of a complex centromere, we examined whether any sequences within S. pombe centromere II (cen2) have the ability to mediate autonomous replication. We found a high density of segments with such activity, including at least eight different regions comprising most of the repeated and unique centromeric DNA elements. A physical mapping analysis using two-dimensional gels showed that autonomous replication initiated within the S. pombe sequences in each plasmid. A two-dimensional gel analysis of replication on the chromosomes revealed that the K and L repeat elements, which occur in multiple copies at all three centromeres and comprise approximately 70% of total centromeric DNA mass in S. pombe, are both sites of replication initiation. In contrast, the unique cen2 central core, which contains multiple segments that can support autonomous replication, appears to be repressed for initiation on the chromosome. We discuss the implications of these findings for our understanding of DNA replication and centromere function.

Base Sequence↗
PubMed1995

Psychiatric nursing and electroconvulsive therapy.

Sufficient doubt surrounds electroconvulsive therapy (ECT) to warrant nurses opting out of its administration and/or advising patients that it may be only one of a range of treatments open to them. In the latter respect, this discussion touches on aspects of the concept of advocacy. Relationships with the medical profession are also considered, as is the indefatigable attention given to issues of 'professional status' by nurses; this preoccupation facilitates an avoidance of therapeutic/advocacy issues.

Electroconvulsive Therapy↗
PubMed1995

Novel Methods of Evaluating the Growth Response Patterns of Treated Brain Tumors.

Unique methods for determining exact borders of intra-axial brain tumors using magnetic resonance imaging-based, computer-assisted, and automated systems are currently under development at the H. Lee Moffitt Cancer Center & Research Institute. Detection of tumor growth rate changes may be obtained more accurately and easily, leading to improved patient care through early institution of effective, new chemotherapy and radiotherapy regimens.

Journal Article↗