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Biomedical subjects

K Winter

Publications and source records attributed to K Winter.

At least 37 records · Page 2Linked to original sources
PubMed1997

Clinical utility of contrast-enhanced MR angiography.

MR angiography (MRA) is a technique under ongoing discussion. Its non-invasiveness and sensitivity to flow irregularities make it an investigational technique which is easy to apply but which does not always lead to comprehensive results. It requires special skill to perform and also experience for correct interpretation of the results. The lengthiness of the procedure combined with certain physical properties tends to limit its use to mostly neurovascular applications. With the introduction of ultrafast MRA in conjunction with peripheral bolus-injection of extracellular contrast media, a new approach to the imaging of such regions as the thoracic and abdominal vasculature not to mention other vascular territories has become possible. In this paper, considerations of bolus and measurement optimization and timing protocols for dedicated indications are presented together with an overview on the experience acquired to date for CE-MRA of the carotid artery, mediastinal and pulmonary vessels, abdominal vasculature, and peripheral vessels. The main advantage of ultrafast CE-MRA is that patients are subjected to much more tolerable breath-hold investigations with the result that physiological motion such as peristalsis or major pulsation is minimised.

Adolescent↗
PubMed1997

[MR angiography of thoracic blood vessels].

Through the introduction of newly invented high-performance gradient systems to MRI, which enable for echoplanar imaging (EPI), also magnetic resonance angiography (MRA) has gained an entirely new field of applications and techniques. Ultrafast imaging techniques in MRA allow the investigation of larger vascular areas within a single breath-hold-period. Artifacts like motion induced signal misregistrations, dephasing or saturation of the vascular signal are minimized by extremely short echo times. The technique thus requires the intravenous application of a contrast media bolus, usually a gadolinium compound, which is in standard clinical use. Coordination of the bolus injection and the timing of the data acquisition is crucial for optimal results. The first pass evaluation of the contrast media resembles CTA to a certain extend. Due to the fast measurement and the high contrast in contrast-enhanced MRA (CE-MRA) new applications and indications are developed like MRA of the pulmonary vessels. The paper offers considerations and trials for optimization of thoracical CE-MRA. Besides parameter constellation also bolus-optimization is described with respect to the dedicated anatomical premises. Investigations on volunteers and on patients build a basis for suggestions of optimized CE-MRA procedures. To date, a final estimation of the clinical value of the new technique cannot be given since ongoing improvements change the optimal protocol frequently and the potential of further developments is high.

Adolescent↗
PubMed1994

[Flow cytometry detected S-phase fraction and ploidy as prognostic parameters in primary, node-negative breast cancer].

100 specimens of patients with primary node-negative breast cancer were examined by flow cytometry. 64 tumours were shown to be diploid and 36 tumours were aneuploid. The median was the cut-off level for tumours with low S-phase (< or = 10.9%) and high S-phase values (> 10.9%). Aneuploid tumours were associated with high S-phase fraction. The average length of follow-up was 42 months. In univariate analysis for disease-free survival, diploid tumours were shown to have a slightly better prognosis than aneuploid tumours (p = 0.07). This trend could not be shown in multivariate analysis. The S-phase fraction proved to be an independent prognostic factor. Patients, whose tumours had S-phase fractions < or = 10.9%, had significantly longer disease-free survival in univariate (long-rank-test: p = 0.021), as well as in multivariate analysis according to the Cox regression model (p = 0.033). Since, as already stated, the S-phase fraction is an independent prognostic factor for node-negative breast cancer, further adjuvant therapy studies should take this factor into consideration.

Adult↗
PubMed1993

[Determination of drug availability from commercial topical formulations with a multilayer membrane model].

Using the multilayer membrane system (MMS) the drug availability of four drugs from commercial topical formulations are determined. It was found that the availability differs when commercial formulations of beta-methasone-17-valerate, hydrocortisone, diclofenac-Na and clotrimazole were studied. It is shown that the drug availability for characterizing topical formulations has to be taken into account. The MMS applied in this study can be used for the determination of this parameter.

Administration, Topical↗
PubMed1992

Regulatory protein phosphorylation of phosphoenolpyruvate carboxylase in the facultative crassulacean-acid-metabolism plant Mesembryanthemum crystallinum L.

Phosphoenolpyruvate PyrP carboxylase (PyrPC) and PyrPC kinase were copurified from dark-adapted leaves of the common ice plant Mesembryanthemum crystallinum L. with crassulacean-acid metabolism (CAM). Purification by (NH4)2SO4 fractionation, chromatography on Fractogel-DEAE and hydroxylapatite resulted in a PyrPC preparation with a specific activity of 23-25 U/mg protein and a protein kinase activity of 255 mumol Pi.mol-1 PyrPC.s-1. After in vitro phosphorylation, the most prominently phosphorylated polypeptide was identified as PyrPC by immunoblotting and sequencing. Phosphorylation of PyrPC in vitro by incubation with 400 microM MgATP decreased its sensitivity towards malate. When purified in the absence of the protease inhibitor chymostatin, PyrPC lost an N-terminal sequence of 128 amino acids. Although the carboxylation reaction was unaffected, the truncated PyrPC could neither be phosphorylated in vitro nor inhibited by malate. This result and data obtained by limited proteolysis concur with the hypothesis [Jiao, J.A. & Chollet, R. (1989) Arch. Biochem. Biophys. 283, 300-305] that Ser11 is the phosphorylation site of the CAM PyrPC of M. crystallinum. At pH 7.0, the Km for ATP of the protein kinase was 25 microM; phosphorylation of PyrPC was maximal after 30 min at pH 7.0. The kinase showed also activity with histone III-S but not with dephosphorylated casein. It was inhibited by malate. The results show, that reversible protein phosphorylation is an important factor in the regulation of PyrPC in the facultative CAM plant M. crystallinum, similar to C4 and constitutive CAM plants.

Adenosine Triphosphate↗
PubMed1992

[Intrauterine pericardial effusion. Early symptom of a primary symptomatic congenital cytomegaly].

We report of a fetus who was ultrasonographically shown to have growth retardation, oligohydramnios and a pericardial effusion without other components of a hydrops fetalis at 28 weeks' gestation. At 29 weeks' gestation the child was born by cesarean section of pathological CTG. A congenital cytomegaly was diagnosed. The etiological role of the infection for the development of the pericardial effusion is discussed.

Adult↗
PubMed1991

Salivary cortisol in children: correlations with serum values and effect of psychotropic drug administration.

This study compares the paired serum and salivary cortisol levels of 60 children and adolescents, obtained while performing a routine Dexamethasone Suppression Test. The results reveal significant correlations between serum and salivary cortisol levels in both drug-free (r = 0.90, p less than .001) and medicated patients (r = 0.81, p less than .001). Multiple regression analysis suggests that, while the slopes of the two regression curves are parallel (0.15 less than p less than 0.20), the intercepts are significantly different (p less than 0.05). This study supports the use of salivary measures of cortisol for children and adolescents. The authors suggest care in the use these measures while the patient is taking psychotropic medication.

Adolescent↗
PubMed1987

Magnetic resonance imaging in non-specific discitis.

In this 20-month-old girl with non-specific spondylodiscitis the typical clinical presentation was absent. A definite diagnosis was made by radiological examination. Several reports have appeared in the literature concerning the importance of MRI as a new imaging modality in the diseases of the spine, including spondylodiscitis. In the present report we discuss the potential role of MRI in early diagnosis of spondylodiscitis in childhood.

Female↗
PubMed1985

[Sialochemical and morphology studies of the submandibular gland of the diabetic patient--a contribution to diabetic sialadenosis].

Sixty-four sialochemical and six morphological examinations were carried out on diabetics with swollen glandula submaxillaris. The significant decrease of the sodium content, the significant increase of potassium content as well as the significantly decreased amylase content of submaxillary saliva speak for diabetogenous sialadenosis. The microscopical and ultramicroscopical findings in needle biopsies confirm the morphological pattern of sialadenosis in the diabetic submaxillary gland.

Amylases↗
PubMed1983

Effect of serotonin uptake inhibition by zimelidine on hypothalamic-pituitary-adrenal activity.

Plasma ACTH levels after oral ingestion of 2 g metyrapone at 24.00 hours in six healthy subjects were higher after pretreatment with zimelidine (300 mg) in comparison to placebo. Since zimelidine is a relatively selective serotonin reuptake inhibitor its action on hypothalamic-pituitary-adrenal (HPA) activity suggests that serotonin is a potent stimulator of ACTH release. The ratio of cortisol to 11-deoxycortisol was taken as a measure of 11-hydroxylase activity, which indicates biological activity of secreted ACTH. These cortisol/11-deoxycortisol ratios were significantly increased after zimelidine treatment, when compared to placebo. Both the ACTH response and the cortisol/11-deoxycortisol ratios substantiate evidence derived from animal experiments, indicating a stimulatory influence of serotonin on HPA activity. No firm conclusion, however, may be drawn on by which mechanism zimelidine exerts its action on the HPA-axis. Moreover these findings provide no information on whether serotonin has a stimulatory role on ACTH production under physiological condition.

Adrenocorticotropic Hormone↗