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Biomedical subjects

T Koch

Publications and source records attributed to T Koch.

At least 181 records · Page 10Linked to original sources
PubMed1996

The biomedical construction of ageing: implications for nursing care of older people.

This paper reports on an existential phenomenological study carried out in a care of elderly people setting in a 1000-bed hospital in the United Kingdom. Fourteen participants were interviewed, each on several occasions. Two themes derived from these narratives are discussed, revealing negative experiences which are related to feelings of powerlessness. These two themes, routine geriatric style and segregation, are shown to arise from the history and culture of the wards and are shown to result in care deprivation and depersonalization. Patients' individual needs are ignored as they become the objects of inflexible routines within health care practice. In order to understand the situation, the history of care of older people and the biomedical construction of ageing are examined. It is concluded that what is needed is a wider social and political movement which opposes ageism and challenges ageist stereotypes. In addition, in health care there is a need for a review of the routine geriatric style of care and of segregation based on age and a social gerontology programme for nurse education.

Activities of Daily Living↗
PubMed1996

Implementation of a hermeneutic inquiry in nursing: philosophy, rigour and representation.

The thesis of this paper is that researchers working in interpretive traditions need to address three central issues: philosophy, rigour and representation. This paper discusses the process of an hermeneutic inquiry as a research methodology used in seeking to understand the experiences of older patients admitted to an acute hospital. The methodology includes the philosophical framework and assumptions underpinning the research. Philosophical hermeneutics guides the inquiry as a reflection of the research process. Three issues concerning legitimation of the hermeneutic research process arise: the philosophical underpinnings of the methodology, representation, or the participation of the researcher in making data, and rigour, or the way in which trustworthiness of hermeneutic research can be established. I recommend that Gadamer's primacy of application to the understanding of texts can also be applied to understanding of health environments. I conclude that Gadamer's post-modern sensibility regarding text and the framework of Guba & Lincoln's fourth generation evaluation are compatible within a hermeneutic inquiry.

Acute Disease↗
PubMed1996

Alteration of n-3 fatty acid composition in lung tissue after short-term infusion of fish oil emulsion attenuates inflammatory vascular reaction.

OBJECTIVES: To investigate whether modulation of the fatty acid profile can be achieved by the short-term infusion of a fish oil emulsion which may attenuate the pulmonary response to inflammatory stimulation. Changes of fatty acid pattern in-lung tissue and perfusate were analyzed and correlated with physiologic data after a 3-hr infusion of fish oil in comparison with a soybean oil preparation. DESIGN: Prospective, randomized, controlled trial. SETTING: Experimental laboratory in a university teaching hospital. SUBJECTS: Forty standard breed rabbits of either gender. INTERVENTIONS: Isolated lungs from anesthetized rabbits were ventilated and recirculation-perfused (200 mL/min) with 200 mL of cell-free buffer solution to which either 2 mL of saline (control, n = 6), 2 mL of a 10% soybean oil preparation (n = 6), or 2 mL of a 10% fish oil emulsion (n = 6) were added. Samples of perfusate and lung tissue were collected for analysis of fatty acid composition. Tissue and perfusate fatty acid composition were analyzed by capillary gas chromatography. To study metabolic alterations in states of inflammatory stimulation, lungs of each group were stimulated with small doses of the calcium ionophore, A23187 (10(-8) M), during the 180-min lipid perfusion period and again after washing out the lipids by exchanging the perfusion fluid. Pulmonary arterial pressure and lung weight gain were monitored, and eicosanoids were analyzed in the perfusate. MEASUREMENTS AND MAIN RESULTS: Free eicosapentaenoic acids increased several-fold in lung tissue and perfusate during a 3-hr infusion with fish oil. The intravenously administered n-3 fatty acids were rapidly hydrolyzed, as indicated by the appearance of substantial quantities of eicosapentaenoic acid in the perfusate free fatty acid fraction. This increase of perfusion levels of eicosapentaenoic acid was paralleled by an attenuated pressure increase and edema formation due to calcium ionophore challenge and an altered eicosanoid spectrum determined in the perfusate compared with soybean oil-treated lungs. CONCLUSION: Short-term n-3 lipid application (fish oil emulsion) exerts anti-inflammatory effects on lung vasculature, which may be due to the metabolism of eicosapentaenoic acid resulting in the generation of less potent inflammatory eicosanoids.

Animals↗
PubMed1996

Effects of N-acetylcysteine on bacterial clearance.

The aim of this study was to investigate whether the oxygen radical scavenger N-acetylcysteine (N-AC) impairs bacterial clearance, thus predisposing the host to increased risk of disease. Blood clearance of Escherichia coli and organ colonization were investigated in anaesthetized rabbits after pretreatment with N-AC (250 mg kg-1 body weight, n = 16) and in sham-operated animals (n = 12). To enable quantification of the clearance process, defined numbers of exogenous E. coli [1.3 x 108 colony-forming units (CFUs)] were injected intravenously. Parameters monitored were kinetics of bacterial elimination from the blood, and polymorphonuclear leucocyte (PMN) oxidative burst activity. Samples of liver, kidney, spleen and lung were collected for bacterial counts. Compared with controls, pretreatment with N-AC resulted in delayed bacterial elimination from blood and higher organ colonization with increased numbers of E. coli in liver, lung and kidney (P < 0.05). N-AC treatment was associated with a suppressed PMN oxidative burst activity. Impaired bacterial clearance and enhanced organ colonization in N-AC-treated animals correlated with reduced oxidative burst activity, suggesting impaired granulocyte-dependent bacterial killing due to N-AC application.

Acetylcysteine↗
PubMed1996

[A new procedure for determining leg length and leg length inequality using ultrasound. II: Comparison of ultrasound, teleradiography and 2 clinical procedures in 50 patients].

The clinical methods still in common use for measuring leg length and leg length discrepancy (LLD) cannot always meet the demands of precision and accuracy. A method using ultrasound is presented and shown to be a standardized, non-invasive method allowing accurate determination of leg length and LLD. Once the validity had been proved experimentally, practical handling, precision and accuracy of this method were tested on 50 patients in whom teleradiography of the lower extremity was performed for different reasons. The sonographically determined measures of LLD were compared with the radiographic measurements and in addition clinical measurements were taken by direct (tape measure) and indirect methods ("lengthening" of the shorter leg by wooden blocks of known thickness). Adjustments to the ventral hip joint and to the medial knee joint served as standardized, easily reproducible sonographic reference points. The mean variance of repeated sonographic measurements as a reflection of precision amounted to 3.5 mm2 for leg length measurement, with a maximum of 13.5 mm2. In the case of LLD the mean divergence between sonographically and radiographically determined LLD was 0.9 +/- 2.7 mm, with a maximum of 6.4 mm. The clinical methods with mean divergence of -1.2 +/- 9.6 mm (direct method) and -1.0 +/- 6.1 mm (indirect method) proved to be less accurate. The method examined for measuring leg lengths and LLD by means of ultrasound is easy to manage and non-invasive. Its precision and accuracy make it superior to clinical measuring methods and could even make some radiographical examinations superfluous.

Adult↗
PubMed1995

Differential Fos-protein induction in rat forebrain regions after acute and long-term haloperidol and clozapine treatment.

Both acute and long-term effects of haloperidol and clozapine on Fos-like immunoreactive nuclei in several rat forebrain areas were quantified. Rats were treated with saline (1 ml/kg.day, control), haloperidol (1 mg/kg.day) and clozapine (20 mg/kg.day) i.p. for 21 days. Two hours before perfusion fixation a single (acute treatment) or last (long-term treatment) dose of the drug was given. Drug-induced catalepsy and gain in body weight were also measured. A single dose of haloperidol produced large increases in Fos-like immunoreactive nuclei in the striatum, the nucleus accumbens and central amygdala. Following long-term treatment these increases were reduced in all nuclei studied, except the lateral septum. Acute clozapine treatment had slight (if any) effects on the number of Fos-like immunoreactivity-expressing nuclei in the striatum, but the increases in the nucleus accumbens, the lateral septum, the paraventricular and supraoptic nuclei of the hypothalamus and the central amygdala were substantial. Long-term clozapine treatment reduced the acute response significantly in all the areas except the nucleus accumbens. Both haloperidol and clozapine treatment reduced the weight gain of the rats. Haloperidol, but not clozapine, induced catalepsy that remained maximal during the long-term haloperidol treatment. These results indicate that in most brain areas high Fos-protein levels are not necessary to maintain antipsychotic activity or side-effects. The persisting effect of clozapine in the nucleus accumbens may be of significance to the efficacy of this drug in treatment-refractory schizophrenia.

Animals↗
PubMed1995

Influence of B2 receptor antagonists on bradykinin-induced vasodilation and edema formation in isolated rabbit hindlimbs.

In search of new possibilities to prevent acute inflammatory vascular reaction, we examined the effect of two selective B2 receptor antagonists, CP 0127 ([Bissuccimidohexane (L-Cys6)-1] and HOE 140 (D-Arg[Hyp3, Thi5, D-Tic7, Oic8]BK), on changes in perfusion pressure and on edema formation caused by bradykinin (BK) in the isolated perfused rabbit hindlimbs. CP 0127 and HOE 140 were added to the perfusion fluid 2 min prior to the first BK-administration (5 x 10(-9) mol/l). A second BK-stimulation was performed after 30 minutes. The antagonists were tested in groups of 6 experiments each at concentrations of 10(-6) mol/l, 5 x 10(-9) mol/l and 10(-10) mol/l. CP 0127 was also tested in a concentration of 10(-8) mol/l. The application of BK resulted in an acute decrease of the mean arterial pressure and in a continual edema formation, reflected by an increase of organ weight (controls, n = 6). Pretreatment with CP 0127 as well as with HOE 140 attenuated dose-dependently the BK-induced vasodilation (p < 0.005) and edema formation. The current results indicate that CP 0127 and HOE 140 are able to reduce BK-induced effects on vascular tone and edema formation.

Amino Acid Sequence↗
PubMed1995

Interpretive approaches in nursing research: the influence of Husserl and Heidegger.

This paper aims to throw some light on Husserlian phenomenology and Heideggerian hermeneutics, and to discuss their influences and applicability to the nursing research agenda. There are definite distinctions between Husserlian transcendental phenomenology and Heideggerian hermeneutic phenomenology and these distinctions have implications for the methodology employed. These traditions are discussed with respect to some fundamental research issues: the philosophical perspectives of the traditions and the notion that data that result from the inquiry are created by the interaction between researcher and researched. The central recommendation in this paper is that nurse researchers appraise the philosophical underpinnings of the methodologies they pursue.

Nursing Research↗
PubMed1995

Listening to the voices of older patients: an existential-phenomenological approach to quality assurance.

The motivation behind this study was a desire to gain access to the experiences of elderly people receiving nursing care in hospital. Previous experience with quantitative approaches to quality assurance had led to dissatisfaction with their neglect of the patient perspective or reliance on patient satisfaction questionnaires. An existential-phenomenological approach was used in an attempt to reconstruct patients' experiences as reported in their own words. Themes which emerged from the data and are reported here focus on 'routine geriatric care', 'care deprivation', 'depersonalization', and 'geriatric segregation'. The findings are discussed against the background of literature about nursing care of elderly people. It is suggested that in the setting studied, limitations posed by past management deficiencies, under-staffing and poor physical environment contributed to the situation reported. Trained nurses felt they worked hard to give the best care they could but, with a high ratio of untrained staff and lack of continuing education, they were aware that their levels of achievement were far from ideal. The study demonstrates that, with an appropriate methodology, it is possible to gain access to how patients' experience their care and in this sense the attempt to 'listen to the voices of patients' was successful and gives pointers to developing more patient-sensitive quality-assurance processes.

Aged↗
PubMed1995

Comparison of two second-generation anti-hepatitis C virus ELISA on 21431 US blood donor samples.

We have compared two different second-generation (2.0) enzyme-linked immunosorbent assays (ELISA) for the presence of antibodies to hepatitis C virus (anti-HCV) in blood from volunteer, unpaid donors. At two separate blood centres, a total of 21,431 donor samples were tested with Abbott Anti-HCV 2.0 ELISA and Ortho Anti-HCV 2.0 ELISA. Samples found to be repeatedly reactive were tested by supplemental/investigational assays. MATRIX HCV (Abbott) and anti-HCV RIBA II (Ortho/Chiron), to 'confirm' the presence of anti-HCV. Discordant ELISA samples were additionally tested by the polymerase chain reaction (PCR) for the presence of HCV RNA. The Abbott anti-HCV assay had a repeatedly reactive rate of 0.59% (127/21,431) and the Ortho anti-HCV assay 0.51% (110/21,431). Overall agreement between assays was 99.76%, 72/127 (56.7%) of Abbott repeatedly reactive samples confirmed on MATRIX and 61/127 (48.0%) on RIBAII; 70/110 (63.6%) of Ortho repeatedly reactivate samples confirmed on MATRIX and 61/110 (55.5%) on RIBA II. Discordant ELISA samples tested by PCR yielded negative results. Hence the two ELISA had equal sensitivity, as defined by detection of true positive samples; the slightly lower specificity of the Abbott Anti-HCV 2.0 ELISA may be owing to culling of donors with a false positive test by Ortho's Anti-HCV 1.0 and 2.0 ELISA tests (the routine tests in place at each blood centre). A sample found to be repeatedly reactive by two different ELISA tests for anti-HCV is likely to be a true positive and may not require further 'confirmatory' testing.

Blood Donors↗
PubMed1995

Sequence-specific purification of nucleic acids by PNA-controlled hybrid selection.

Using an oligohistidine peptide nucleic acids (oligohistidine-PNA) chimera, we have developed a rapid hybrid selection method that allows efficient, sequence-specific purification of a target nucleic acid. The method exploits two fundamental features of PNA. First, that PNA binds with high affinity and specificity to its complementary nucleic acid. Second, that amino acids are easily attached to the PNA oligomer during synthesis. We show that a (His)6-PNA chimera exhibits strong binding to chelated Ni2+ ions without compromising its native PNA hybridization properties. We further show that these characteristics allow the (His)6-PNA/DNA complex to be purified by the well-established method of metal ion affinity chromatography using a Ni(2+)-NTA (nitrilotriactic acid) resin. Specificity and efficiency are the touchstones of any nucleic acid purification scheme. We show that the specificity of the (His)6-PNA selection approach is such that oligonucleotides differing by only a single nucleotide can be selectively purified. We also show that large RNAs (2224 nucleotides) can be captured with high efficiency by using multiple (His)6-PNA probes. PNA can hybridize to nucleic acids in low-salt concentrations that destabilize native nucleic acid structures. We demonstrate that this property of PNA can be utilized to purify an oligonucleotide in which the target sequence forms part of an intramolecular stem/loop structure.

Base Composition↗
PubMed1995

Overexpression, purification, and characterization of the ADP-ribosyltransferase (gpAlt) of bacteriophage T4: ADP-ribosylation of E. coli RNA polymerase modulates T4 "early" transcription.

The bacteriophage T4 Alt gene product is a component of the phage head and enters the host cell in the process of infection together with the phage DNA. It immediately ADP-ribosylates host RNA polymerase, presumably at only one of the two alpha-subunits. Transcription from T4 "early" promoters, therefore, might be catalyzed, at least in part, by an altered RNA polymerase. The T4 alt gene was cloned into the expression vector pBluescript. E. coli cells, transformed with this recombinant vector, overexpressed the 76 kDa Alt gene product, which was purified to homogeneity. The purified enzyme not only ADP-ribosylates the alpha-subunit of RNA polymerase, but also subunits beta and beta', as well as the sigma 70-factor. The recombinant enzyme behaved like the native enzyme isolated from mature phage particles. The effect of the ribosylation reaction on the transcription activity of host RNA polymerase was investigated in vivo. It results in a modulation of T4 "early" promoter strengths, presumably, in a number of cases, leading to an overexpression of T4 "early" genes. The degree of overexpression, in some cases, should reach 50%, and seems to be well dosed for each promoter, controlling an individual transcription unit.

Amino Acid Sequence↗