Search PubMed⌕ Search

Biomedical subjects

K Walter

Publications and source records attributed to K Walter.

At least 73 records · Page 4Linked to original sources
PubMed1994

Rate and gender dependence of the sweating, vasoconstriction, and shivering thresholds in humans.

BACKGROUND: The range of core temperatures not triggering thermoregulatory responses ("interthreshold range") remains to be determined in humans. Although the rates at which perioperative core temperatures vary typically range from 0.5 to 2 degrees C/h, the thermoregulatory contribution of different core cooling rates also remains unknown. In addition, sweating in women is triggered at a slightly greater core temperature than in men. However, it is unknown whether the vasoconstriction and shivering thresholds are comparably greater in women, or if women tolerate a larger range of core temperatures without triggering thermoregulatory responses. Accordingly, the authors sought to (1) define the interthreshold range; (2) test the hypothesis that, at a constant skin temperature, the vasoconstriction and shivering thresholds are greater during rapid core cooling than during slowly induced hypothermia; and (3) compare the sweating, vasoconstriction, and shivering thresholds in men and women. METHODS: Eight men and eight women participated. The men participated on 2 separate days; no anesthesia or sedatives were administered. On each day, they were cutaneously warmed until sweating was induced and then were cooled by a central venous infusion of cold fluid. The cooling rates were 0.7 +/- 0.1 degrees C/h on 1 day and 1.7 +/- 0.4 degrees C/h on the other, randomly ordered. Skin temperature was maintained near 36.7 degrees C throughout each trial. The women were studied only once, in the follicular phase of their menstrual cycles, at the greater cooling rate. RESULTS: The interthreshold range was approximately 0.2 degrees C in both men and women, but all thermoregulatory response thresholds were approximately 0.3 degrees C higher in women. All thresholds were virtually identical during slow and fast core cooling. CONCLUSIONS: Our findings confirm the existence of an interthreshold range and document that its magnitude is small. They also demonstrate that the interthreshold range does not differ in men and women, but that women thermoregulate at a significantly higher temperature than do men. Typical clinical rates of core cooling do not alter thermoregulatory responses.

Adult↗
PubMed1994

[The bioavailability of enteric coated diclofenac formulations. 2. Bioavailability following single administration of a multiple-unit formulation in comparison to a single-unit formulation under fasting and non-fasting conditions].

Relative bioavailability of enteric-coated diclofenac (CAS 15307-86-5) was investigated after a single-dose administration of a multiple-unit formulation (Diclo-Puren 50, test) in comparison to a single-unit formulation (reference). The study was carried out in a four-way change-over design including a group of 12 healthy male volunteers. Each formulation was administered after 10 h of fasting or just after (5 min) finishing a meal (standard breakfast). Diclofenac plasma concentrations were measured using a selective and sensitive GLC-MS method after liquid-liquid extraction and derivatisation. Area under the curve (AUC), maximum plasma concentrations (Cmax), time of maximum plasma concentration (tmax), time of delay of first measurable concentrations (tlag) and plateau time of concentrations above minimum effective concentrations (MEC) of 50 ng/ml (tMEC(50)) and 100 ng/ml (tMEC(100)), respectively, were evaluated as pharmacokinetic characteristics. Additionally, for AUC and Cmax, 90%-confidence intervals (parametric: ANOVA, ANOVAlog, non-parametric: Mann-Whitney) were calculated to evaluate the influence of food on bioavailability of each formulation. Mean (median) relative bioavailabilities of diclofenac of the test formulation (comparison: postprandial vs. fasting conditions) were determined for the test formulation as 96% (103%) and for the reference product as 70% (83%). Mean +/- SD (median) maximum plasma concentrations of the test formulation were determined as 695 +/- 313 (677) ng/ml (fasting) and as 452 +/- 163 (456) ng/ml (postprandial). Maximum plasma concentration occurred 1.2 +/- 0.5 (1.0) h and 4.8 +/- 1.0 (5.0) h after administration, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

[Stem cell apheresis--experiences in children].

Stem cell apheresis, as a means to support patients during aplasia, has become an important support in the management of patients with various malignant diseases in need for heavy therapeutic regimens. Progress in this field is due, among other reasons, to better knowledge of pathophysiology in haematopoiesis and of the functioning of cytokines. Furthermore, the technical feasibility of apheresis has been improved to such an extent as to allow for collection of a stem cell-containing fraction almost in pure form. Our experience with stem cell apheresis is relatively short but includes also children between the ages of 1 and 21 years (median: 5 1/2 years). Whereas the clinical results have been published elsewhere, we here report our experience in terms of safety, using the Fresenius AS 104 machine.

Adolescent↗
PubMed1993

Enhanced coronary blood flow velocity during intraaortic balloon counterpulsation in critically ill patients.

OBJECTIVES: The aim of this study was to assess coronary blood flow during intraaortic balloon counterpulsation by direct measurement. BACKGROUND: In a majority of human studies, increased coronary blood flow during intraaortic balloon counterpulsation measured by indirect techniques has not been consistently demonstrated. METHODS: Hemodynamic variables and coronary blood flow velocity (20-MHz Doppler-tipped catheter) data were measured in 19 patients requiring intraaortic balloon pumping for clinical indications (11 patients had acute myocardial infarction [9 with shock], 6 had unstable angina, 1 had acute mitral regurgitation and 1 was at high risk undergoing angioplasty). Hemodynamic data, mean and phasic diastolic flow velocity and velocity-time integrals (computed from digitized waveforms) were analyzed during periods of 1:1 balloon counterpulsation. RESULTS: Intraaortic balloon pumping decreased systolic pressure (6 +/- 10%, p < 0.001) and increased diastolic pressure (80 +/- 30% from baseline, p < 0.001) without changing RR interval. Peak phasic, mean coronary flow velocity and diastolic flow velocity integral were significantly increased (115 +/- 115%, 67 +/- 61%, 103 +/- 81%, respectively, all p < 0.001) during intraaortic balloon pumping. In addition, although a wide splay of data was evident due to operator set variations in balloon inflation and deflation timing, the greater increases in diastolic flow velocity integral (DFVi) occurred in patients with basal systolic pressure < or = 90 mm Hg (% delta DFVi = 102 - 0.1.[unaugmented systolic pressure], SEE = 21.7 mm Hg, r = 0.30, p < 0.001). CONCLUSIONS: Intraaortic balloon pumping unequivocally and significantly augments proximal coronary blood flow velocity, nearly doubling the coronary flow velocity integral in most patients. This mechanism may be a significant means of ischemia relief in hypotensive patients.

Blood Flow Velocity↗
PubMed1993

[Biological availability of gastric juice-resistant coated diclofenac preparations. 1. Bioavailability study following a single administration of a multiple-unit formulation in comparison with a single-unit formulation].

Bioavailability Study of Enteric Coated Diclofenac Formulations/1st Communication: Bioavailability study following single-dose administration of a multiple-unit formulation compared with a single-unit formulation Relative bioavailability of diclofenac (CAS 15307-86-5) was investigated after single-dose administration of an enteric coated multiple-unit formulation (Diclo-Puren 50, test) in comparison to a single-unit dosage form (reference). The study was carried out in a three-way changeover design with a group of 18 healthy male volunteers. Diclofenac plasma concentrations were measured using a selective and sensitive GLC-MS method after liquid-liquid extraction and subsequent derivatisation. Area under the curve (AUC) and maximum plasma concentrations (Cmax) were evaluated as pharmacokinetic characteristics. Moreover, time of maximum plasma concentration (tmax), lag-time (tlag) and plateau time of concentrations above minimum effective concentrations (MEC) of 50 ng/ml (tMEC(50)) and 100 ng/ml (tMEC(100)), respectively were calculated. Bioequivalence concerning AUC and Cmax was assessed by calculating 90%-confidence intervals using parametric (ANOVA, ANOVAlog) and non-parametric (Mann-Whitney) methods. Due to the inclusion rule bioequivalence was accepted if one of the calculated intervals was completely in the range of 80 to 125% (AUC) and 70 to 143% (Cmax). tmax, tlag and tMEC were evaluated considering the differences of mean values. Individual plasma profiles of diclofenac are more homogeneous after administration of the test formulation than after administration of the reference product. Mean relative bioavailability of the test formulation was calculated as 99%. Maximum plasma concentrations (mean +/- SD) were determined as 1159 +/- 632 ng/ml (test) and as 1481 +/- 637 ng/ml (reference). Maximum plasma concentrations (mean +/- SD) occurred 1.4 +/- 0.7 h (test) and 1.8 +/- 0.7 h (reference) after administration.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Immunohistochemical examination of routinely processed bone marrow biopsies.

Immunohistochemistry was performed on paraffin sections of 169 bone marrow biopsies fixed in a buffered methanol-formalin solution and decalcified with EDTA. The biopsies included specimens with normal hematopoiesis, and specimens that were affected by various hematological disorders as well as some metastatic carcinomas. The results demonstrate that a wide spectrum of antigens was preserved in routinely processed bone marrow biopsies, even after long-term fixation up to 12 days. Markers for granulopoietic cells were lysozyme, elastase, DAKO-M 1, and MT 1. Megakaryopoiesis was stained with glycoprotein IIIa, von Willebrand factor, and Ulex europaeus agglutinin (UEA), and erythropoiesis with LN 1. Normal lymphocytes as well as lymphoma cells of all non-Hodgkin's lymphomas tested were positive for leukocyte common antigen (LCA), and at variable degree, for MB 1, 4 KB 5, LN 1, LN 2, UCHL 1, or MT 1. Reed-Sternberg and Hodgkin's cells in Hodgkin's lymphomas were reactive with Ber-H 2, LN 2 and Dako-M 1. In plasma cell disorders, staining for immunoglobulin light chains gave best results. Metastatic carcinomas showed predominantly staining with EMA, and KL 1. A selected panel of specific cell markers is proposed, which proved to be helpful in routine bone marrow diagnosis in most cases.

Biopsy↗
PubMed1992

That was then: elderly survivors of incest.

1. Psychosocial ramifications of incest last a lifetime for some and may be of crucial importance in treating patients in the later developmental stages of life. 2. Nursing assessments that include current and past history of violence are important for understanding presenting symptomology and interpersonal dynamics, but they are often neglected. 3. There is a need for nursing research that looks at all facets of elderly incest survivors, including incidence, late life symptomology, and special treatment needs.

Adolescent↗
PubMed1991

The nutcracker syndrome: new aspects of pathophysiology, diagnosis and treatment.

Magnetic resonance imaging (MRI) was used to study vascular anatomy in 3 patients with the nutcracker syndrome and in 10 healthy volunteers. From these studies an abnormal branching of the superior mesenteric artery from the aorta was identified as being the cause of the nutcracker syndrome. Consequently, surgical transposition of the left renal vein to achieve an unobstructed renal venous backflow was performed successfully in 2 patients, while 1 underwent nephrectomy. In 1 patient adjuvant ureteral instrumentation became necessary to aid occlusion of persisting shunts between peripelvic venous varicosities and the urinary tract. Awareness of the pathophysiology of the nutcracker syndrome ensures an early diagnosis, which should be confirmed by a combination of diagnostic procedures, including MRI.

Adult↗
PubMed1991

[Color processing of ultrasonographic images in extracorporeal lithotripsy].

A number of technical difficulties are encountered in the ultrasonographic detection of renal stones which unfortunately limit its performance. The margin of error of firing in extracorporeal shock-wave lithotripsy (ESWL) must be reduced to a minimum. The role of the ultrasonographic monitoring during lithotripsy is also essential: continuous control of the focussing of the short-wave beamand assessment if the quality of fragmentation. The authors propose to improve ultrasonographic imaging in ESWL by means of intraoperative colour processing of the stone. Each shot must be directed to its target with an economy of vision avoiding excessive fatigue. The principle of the technique consists of digitalization of the ultrasound video images using a Macintosh Mac 2 computer. The Graphis Paint II program is interfaced directly with the Quick Capture card and recovers the images on its work surface in real time. The program is then able to attribute to each of these 256 shades of grey any one of the 16.6 million colours of the Macintosh universe with specific intensity and saturation. During fragmentation, using the principle of a palette, the stone changes colour from green to red indicating complete fragmentation. A Color Space card converts the digital image obtained into a video analogue source which is visualized on the monitor. It can be superimposed and/or juxtaposed with the source image by means of a multi-standard mixing table. Colour processing of ultrasonographic images in extracoporeal shockwave lithotripsy allows better visualization of the stones and better follow-up of fragmentation and allows the shockwave treatment to be stopped earlier. It increases the stone-free performance at 6 months. This configuration will eventually be able to integrate into the ultrasound apparatus itself.

Color↗
PubMed1989

[Clinical epidemiology using an electronic value-added tabulator. Application to cancer of the prostate in TNM classification and in calculating Kaplan-Meier curves].

The authors have been using the WHO-TNM 1977 classified, modified in 1982, for prostatic cancer for more than ten years. This classification has been considered to be insufficient to allow precise choice of therapeutic determinants and to accurately evaluate the results of treatments. A new WHO TNM 88 classification has been recently published and has raised many controversies in the urological literature which complicates the development of this classification. The authors have developed a value added system of TNM scoring using the Excel programme on a personal computer, which tries to integrate the various classifications 78-82-88. Very precise rules must be determined for information collection, the most reproducible medical indicators must be selected and they must be made as objective and as pertinent as possible. The rules of the WHO classification must then be formalized and introduced into the expert system as rules of production. The system allows optimal transcription of the scores from one classification to another, depending on the political orientations of the necessity of translation. Lastly, the system calculates, in real time, the actuarial survival and/or Kaplan-Meier curves for all of the events identified by an indicator for the patient files entered into the system.

Electronic Data Processing↗
PubMed1988

Binding of drugs to human skin: influencing factors and the role of tissue lipids.

For a series of ten drugs with different physicochemical properties, binding to human skin (epidermis and corium) was determined. Epidermis was obtained by suction blistering, and corium was sliced with a microtome (0.2 mm). Binding experiments were performed in dialysis chambers, containing labelled drug solutions. All drugs investigated were bound to epidermis and corium. With one exception, epidermal drug binding was significantly higher than corial binding. Nevertheless, a good correlation between binding of drugs to both skin fractions could be found. In a range from 10(-7) to 10(-3) mol L-1 binding of drugs to both skin fractions is linear and not saturable. A good correlation was found between binding and lipophilicity of drugs, determined as the partition coefficients between an organic phase (octanol or heptane) and phosphate buffer of pH 7.0. The results show that binding to epidermis and corium is not saturable and depends on lipophilicity of drugs, indicating unspecific binding. Further binding experiments were performed with lipid-depleted tissue. Since drug binding to lipid-depleted samples and control samples differ only to a moderate extent, it is suggested, that tissue lipids play a marginal role on drug binding. Hence, drugs are bound to human skin by other components like proteins.

Chemical Phenomena↗
PubMed1985

Double-blind comparison of haloperidol decanoate and fluphenazine decanoate effectiveness, side-effects, dosage and serum levels during a six months' treatment for relapse prevention.

In this present study 31 schizophrenic patients were treated for six months for relapse prevention under double-blind conditions with either haloperidol decanoate (22) or fluphenazine decanoate (9). In respect of the prophylactic action, both depot neuroleptics proved to be equal during the comparatively short period of observation. In both groups a psychotic relapse occurred that could not be managed by increasing the depot dosage. No side-effects worth mentioning appeared in either group of patients; patients under haloperidol decanoate, however, only required half the quantity of anti-parkinson medication as compared with patients treated with fluphenazine decanoate, and also displayed extrapyramidal motor symptoms (EPMS) to a lesser degree. Patients received a mean monthly injection of 80 mg of Haloperidol, reaching steady-state serum levels of about 3 ng/ml in the third injection interval. Fluphenazine serum levels known so far for seven patients amount to 0.8 ng/ml after fluphenazine injections of 21 mg every 14 days.

Adult↗