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Biomedical subjects

T Koch

Publications and source records attributed to T Koch.

At least 217 records · Page 12Linked to original sources
PubMed1992

A review of nursing quality assurance.

This paper presents an overview of frameworks used in nursing quality assurance, an outline of the quality assurance movement in nursing, and its current concerns. It is argued that quality assurance activity appears to be propelled by market forces, regulation, coercion and professionalism. The concern with measurement places quality assurance activity within the quantitative paradigm. The problems associated with measurement are discussed and the writer presents qualitative research as a complementary approach to quality assurance and improving care.

Education, Nursing↗
PubMed1992

Alterations of filtration coefficients in pulmonary edema of different pathogenesis.

Different pathomechanisms in the development of pulmonary edema are being discussed. We investigated the effect of pathogenetically varying forms of edema on lung vascular barrier function in isolated cell-free perfused rabbit lungs. As an index of permeability, capillary filtration coefficients (Kfc) were determined from the slope of lung weight change over periods of stepwise venous pressure elevation (5, 7.5, and 10 mmHg) before (controls) and 60 min after edema induction. Edema was induced by venous congestion (n = 6), by application of arachidonic acid in the presence of diclofenac sodium (n = 6), and by elastase application (n = 6). Control values ranged from 0.28 to 0.51 ml.min-1 x mmHg-1 x 100 g-1. Kfc was significantly enhanced after edema induction up to 243% of control value in the hydrostatic edema, 357% in the arachidonic acid edema, and 594% in the elastase edema. When the alterations in capillary filtration due to the different types of edema were compared, Kfc was significantly higher in the proteinase edema, indicating an irreversibly damaged barrier function. These data exemplify different pathophysiological characteristics due to the pathogenesis of interstitial edema formation.

Airway Resistance↗
PubMed1992

Evolution of white matter lesions in neurofibromatosis type 1: MR findings.

To characterize further the evolution of white matter lesions in neurofibromatosis type 1, we reviewed 68 MR images in 43 patients (age, 1-31 years), including 25 follow-up studies (mean interval, 27 months). Lesion number, location, morphology, signal characteristics, and contrast enhancement were assessed. Lesion characteristics and changes thereof were correlated with the patients' ages. Thirty-four patients (79%) had white matter lesions. These lesions were hyperintense on T2-weighted images, were isointense on T1-weighted images, and showed no mass effect or contrast enhancement in 31 patients; in three patients, T1-prolongation was observed (one with significant mass effect). None of the lesions evolved into a glioma. The most common locations were the cerebellum (49%), brainstem (22%), and internal capsule (19%). Nineteen patients had white matter lesions and follow-up studies. Lesions decreased in size or number in seven patients (average age, 13 years), showed no change in three (average age, 12 years), increased in size or number in four (average age, 5 years), and showed a mixed pattern (increased/decreased size/number) in four (average age, 7 years). White matter lesions in neurofibromatosis type 1 frequently increase in size or number early in childhood; this did not indicate neoplasia in our study. The lesions tend to resolve with increasing age. Lesion progression in a child more than 10 years old warrants close follow-up to rule out a neoplasm.

Adolescent↗
PubMed1992

[Late results of endonasal ethmoid bone operation with special reference to polypous sinusitis].

Out of total of 164 patients with chronic sinusitis undergoing intranasal microsurgery, 94 patients were submitted to a detailed analysis one year later. The patients were divided into groups of polypoid and hyperplastic sinusitis, depending on the morphological appearances and the histology of the tissue removed. Patients with polyps showed a significantly higher rate of recurrent (47%) than patients with hyperplastic sinusitis (8.6%). Allergy or bronchial asthma did not influence significantly the rate of recurrence in patients with nasal polyposis, whereas patients with a hyperplastic sinusitis showed a higher recurrence rate if they were atopic as well. However, even patients with polypoid sinusitis gained marked long-term relief of nasal obstruction and other symptoms.

Asthma↗
PubMed1991

Inhibition of adenylate-cyclase-coupled G protein complex by ototoxic diuretics and cis-platinum in the inner ear of the guinea pig.

The enzyme adenylate cyclase produces the second messenger cAMP and is located in the mammalian inner ear, predominantly in the stria vascularis and to a lesser extent in the organ of Corti. It is coupled to hormone receptors and regulating G proteins in the outer cell membrane. By means of immunofluorescence in cryostat sections of the guinea pig cochlea, we could demonstrate the G proteins Gs and Gi, which belong to the adenylate cyclase complex. These proteins had their highest density in the stria vascularis. In membrane preparations of this tissue, the adenylate cyclase complex was inhibited by ototoxic drugs (furosemide, ethacrynic acid and cis-platinum). Stimulation at different sites of the enzyme system showed that the target of these drugs was probably the regulating G protein complex and not the enzyme molecule itself. Inhibition depended on the concentration of the drug and the incubation time.

Adenylyl Cyclase Inhibitors↗
PubMed1991

[Allergic origin of recurrent middle ear effusion and adenoids in young children].

Recurrent middle ear effusions and adenoids in children might be caused by mechanical obstruction, infection or allergy. From 1989 to 1990 we examined 35 infants with no history of allergic rhinitis but with recurrent adenoids and middle ear effusions. During operation a skin test was performed for common allergens. Afterwards we tried to identify these allergens by RAST tests on tissue homogenates from the removed adenoids, the middle ear effusion and serum samples. Additionally the IgE levels were determined and the adenoid tissue was examined for eosinophils. In 12 of our 35 children (34%) the skin tests showed an allergy, mostly to different kinds of pollen or house dust. From these positive patients the respective allergens could be determined by RAST tests in serum in 84%, in tissue homogenates from the adenoids in 41% and in the middle ear effusions in 50% of cases. 50% of the children with positive skin tests showed an eosinophilia in the adenoid tissue. We did not find any allergen in the RAST of the infants with negative skin tests. The data show a correlation of allergen specific IgE antibodies in the serum of our patients and in the middle ear and the nasopharynx. Together with an eosinophilia these results suggest an allergic genesis of recurrent middle ear effusions and adenoids in about 20% to 30% of our cases. Early diagnostic procedures to rule out allergy in children with appropriate clinical symptoms are useful, and in positive cases antiallergic treatment is recommended.

Adenoids↗
PubMed1991

[Diagnostic value of the prick test and tissue RAST in allergic nasal polyposis].

Nasal polyposis is often accompanied by an allergy against inhaled allergens or various foods and drugs. We studied the relationship between nasal polyposis and type-I allergy, using a preoperative skin test on 43 patients with nasal polyposis. This was followed by RAST test of serum, nasal secretion and homogenized tissue from the polyps removed. The rest of the polyp material was examined histologically and cytologically for tissue eosinophilia. A type-I allergy was proved in 40% of the patients by the presence of the same IgE antibodies in the skin test and all the RASTs, accompanied by a distinct eosinophilia in the polyp tissue. In a further 40% of the cases most of the tests were positive, suggesting a probable allergic disposition. These results support the theory of an allergic genesis of many nasal polyps. The tissue RAST especially is of great diagnostic value. Thus, postoperative anti-allergic treatment of these patients should be successful.

Allergens↗
PubMed1990

Fc receptor phosphorylation during receptor-mediated control of B-cell activation.

It is well known that Fc receptors for IgG (FcRII) on macrophages mediate the endocytosis of antibody-antigen complexes and signal the release of inflammatory and cytotoxic agents. FcRII are also expressed at high levels on B cells where they are less involved in endocytosis than in modulating B-cell activation by membrane immunoglobulins. Although crosslinking of membrane immunoglobulins can result in B-cell differentiation and proliferation through stimulation of phospholipase C, mobilization of intracellular Ca2+, and activation of protein kinase C, crosslinking FcR with membrane immunoglobulins confers a dominant inhibitory signal that prevents or aborts activation. This form of regulation may have a role in the induction of tolerance by IgG and in controlling the B-cell repertoire by anti-idiotypes. The different functions of FcR on B cells and macrophages may reflect the fact that these cell types express closely related but distinct FcR isoforms. We have recently found that the main lymphocyte FcR isoform, FcRII-B1, is unable to mediate endocytosis by way of coated pits and coated vesicles owing to an in-frame insertion of 47 amino acids in its cytoplasmic tail. Here we show that this insert, absent from the FcRII-B2 macrophage isoform, also contains serine phosphorylation sites that may have a role in the ability of FcR to regulate B-cell activation through membrane immunoglobulins.

Alkaloids↗
PubMed1990

Sensorineural hearing loss owing to deficient G proteins in patients with pseudohypoparathyroidism: results of a multicentre study.

Pseudohypoparathyroidism (PHP) is a rare disorder that might be caused by an hereditary defect in the G protein system. These membrane-bound proteins are responsible for the transduction of biological signals through the outer cell membrane. The investigation of 22 patients with PHP showed a symmetric sensorineural hearing loss in 63.6% of the subjects. In erythrocyte membrane preparations from blood samples of 15 of these patients, we measured the concentration of the stimulatory Gs protein and the inhibitory Gi protein by means of the Western blot analysis using selective antibodies against alpha-subunits of G proteins. In nine of the 15 cases (60%), we found a distinct decrease in the amount of the Gs protein with a partial preponderance of the Gi protein. These patients had a considerable symmetric sensorineural hearing loss. Pathophysiological mechanisms and the possible role of G proteins in the inner ear are discussed.

Adolescent↗
PubMed1990

A new clinical career structure for nurses: trial and evaluation. The South Australian experience.

A new clinical career structure for nurses was planned, introduced, implemented and evaluated in South Australia in 1986. The new structure was based on the Royal Australian Nursing Federation (South Australian Branch) Model, and its trial took place in 11 health units, involving 5000 registered nurses, or one-third of the nurse workforce in South Australia. The findings of the evaluation research were utilized by Government. The sociopolitical context within which the evaluation of the new clinical career structure was implemented is re-examined in this paper.

Career Mobility↗
PubMed1990

[Diagnosis of carotid body tumor by imaging procedures].

The imaging techniques available for the diagnosis of tumors of the glomus caroticum are discussed with reference to four cases (three patients, one with tumor bilaterally). Taking into consideration the practicability and invasiveness of the investigations as well as the risks and costs involved, we propose that the procedures be performed in the following sequence: ultrasonography, Doppler ultrasonography, computed tomography (CT) or (even better) magnetic resonance imaging (MRI), and selective angiography. In most cases where there is a non-inflammatory mass in the neck, ultrasonography and Doppler ultrasonography may be adequate to establish the diagnosis of a glomus caroticum tumor. B-scan ultrasonography reveals an inhomogeneous mass that pushes the carotid arteries apart and an arteriovenous shunt may be seen using the Doppler technique. CT and MRI show the full extent of the tumor and provide information about infiltration of adjacent structures. Selective intra-arterial angiography confirms the diagnosis, demonstrating a profound vascularized tumor in the carotid bifurcation. If angiography leads to identification of an afferent vessel, selective embolization of the tumor may be performed, thus enabling a much safer operation with less blood loss.

Adult↗
PubMed1989

[Relevance of the new tumor marker SCC (squamous cell carcinoma antigen) for the diagnosis and follow-up control of squamous epithelial carcinoma of the head and neck].

The SCC antigen, a tumour marker for squamous cell carcinoma, is already used for the diagnosis and follow-up of carcinoma of the cervix and the lungs. We determined the SCC antigen levels at the time of diagnosis and during therapy in 108 subjects with a squamous cell carcinoma of the head and neck. According to our results and those of other authors, the normal serum range of SCC lies between 0 and 2 ng/ml. Before therapy we found an increased titre in 38.9% of the subjects, being 6.2%, 30.8%, 47.2% and 76.2% for stages T1 to T4 respectively. Thus even some stage T3 and T4 tumours did not express the antigen. No correlation was found between the titre at the time of diagnosis and the grade of differentiation, the site of the tumour, the presence of lymph node or remote metastases, and the sex of the patient. After operation the titres returned to normal within 1 week, but after radiation or chemotherapy the titre decreased more slowly. In recurrent tumours we found a rising titre, which could be measured in several cases some weeks before the recurrence was visible. In the light of the costs and the yield of the method, we suggest determining the serum SCC antigen level once before therapy. If it is increased, subsequent estimates should be done during the succeeding years to allow early diagnosis of a recurrence of the tumour.

Antigens, Neoplasm↗