Biomedical subjects

Matthias Kraemer

Publications and source records attributed to Matthias Kraemer.

6 recordsLinked to original sources

PubMed2006

Present status and perspectives of cell-based therapies for liver diseases.

In recent years the interest in liver cell therapy has been increasing continuously, since the demand for whole liver transplantations in human beings far outweighs the supply. From the clinical point of view, transplantation of hepatocytes or hepatocyte-like cells may represent an alternative to orthotopic liver transplants in acute liver failure, for the correction of genetic disorders resulting in metabolically deficient states, and for late stage liver disease such as cirrhosis. Although the concept of cell therapy for various diseases of the liver is widely accepted, the practical approach in humans often remains difficult. An international expert panel critically discussed the recent published data on clinical and experimental hepatocyte transplantation and the possible role of stem cells in liver tissue repair. This paper aims to summarise the present status of cell based therapies for liver diseases and to identify areas of future preclinical and clinical research.

Cell Transplantation↗

PubMed2006

Physiological monitoring and control in hemodialysis: state of the art and outlook.

Medical devices for monitoring and feedback control of physiological parameters of the dialysis patient were introduced in the early 1990s. They have a wide range of applications, aiming at increasing the safety and ensuring the efficiency of the treatment, and at an improved restoration of physiological conditions, leading to an overall reduction in morbidity and mortality. Such devices include sensors for the measurement of temperature, optical parameters and sound speed in blood, and electrical characteristics of the human body, and other parameters. Essential for the development of these devices is a detailed understanding of the pathophysiological background of a therapeutical problem. There is still a large potential to introduce new devices for further therapy improvement and automation. Also, the size of the hemodialysis market appears attractive; however, a new product has to meet several specific requirements in order to also become commercially successful. This review describes the therapeutic and technical principles of several available devices, reports on concepts for possible future devices, and presents a short overview on the market environment.

Blood Pressure↗

PubMed2005

Prospective, randomized study: proximate PPH stapler vs. LigaSure for hemorrhoidal surgery.

PURPOSE: It has been shown that for hemorrhoidal surgery both LigaSure and stapler cause less pain than diathermy or scissor dissection. This study has attempted to establish which of the less painful alternatives proves best in an unselected series of patients with hemorrhoidal disease. METHODS: Fifty patients were randomized to undergo stapling hemorrhoidopexy or LigaSure hemorrhoidectomy. Parameters investigated were pain (primary parameter), patient satisfaction with treatment, and recovery of personal activity. Other factors investigated were operative result, ease of handling, analgesic requirements, and postoperative course. RESULTS: Both methods were found to be equivalent in all major aspects analyzed. Postoperative pain scores (P = 0.99), patient satisfaction (P = 1), and self-assessment of activity (P = 0.99) were almost identical in both groups of patients. Significant differences were found in none of the numerous factors investigated. CONCLUSION: Both methods can be used safely and without major disadvantage for the patient regardless of stage and extent of hemorrhoidal disease.

Activities of Daily Living↗

PubMed2004

Delayed shrinkage of the brain after ischemic stroke: preliminary observations with voxel-guided morphometry.

BACKGROUND AND PURPOSE: The most important effect of cerebral ischemia is brain infarction. In this magnetic resonance imaging (MRI) study, the authors aimed at assessing postischemic brain atrophy. METHODS: Ten patients suffering from their first acute cerebral ischemia in the territory of the middle cerebral artery were studied retrospectively. Three-dimensional MRI volume scans were recorded in the acute and chronic stage after infarction and analyzed voxel by voxel intraindividually with the newly developed voxel-guided morphometry. RESULTS: Shrinkage of brain tissue was detected in all patients, not only in the perilesional cortical structures but also in contralateral homolog cortex areas and subcortically in the striatum and thalamus. This secondary shrinkage was not related to the size of the infarcts or to the clinical outcome of patients. CONCLUSIONS: Our study suggests that delayed brain atrophy after acute ischemic stroke involved areas anatomically connected with the ischemic brain lesion but nevertheless was accompanied by a simultaneous improvement of the neurological deficit.

Atrophy↗

PubMed2003

Determination of urea distribution volume for Kt/V assessed by conductivity monitoring.

BACKGROUND: Kt/V can be calculated continuously during dialysis without blood samples using the ionic dialysance method. Unlike the usual method using blood samples, a precise value for the patients' urea distribution volume is required. This study compared different methods for the determination of urea distribution volume (V) to evaluate their use in Kt/V measurement, based on conductivity monitoring. METHODS: Ten patients were studied during 40 dialysis sessions. Total body water and V were determined using bioimpedance spectroscopy (BIS), anthropometric data, and blood-based kinetic data. Ionic dialysance was measured by conductivity monitoring. RESULTS: Total body water measured by bioimpedance was determined as VBIS= 37.0 +/- 7.1 L or 49.6 +/- 4.4% of body weight. V determined using ionic dialysance as input to urea kinetic modeling (UKM) was found to correlate well with total body water (VKecn= 36.4 +/- 5.2 L). All anthropometric equations overestimated measured V: VWatson= 40.7 +/- 3.9 L, VHume= 41.8 +/- 2.5 L, VChertow= 44.6 +/- 3.3 L, and VChumlea= 43.1 +/- 2.9 L. Single-pool Kt/V obtained by kinetic modeling was used as reference (Kt/V)SPVV= 1.49 +/- 0.15. Using different Vs as the V component in the ionic dialysance Kt/V, we obtained: Kecn*t/VWatson= 1.34 +/- 0.12, Kecn*t/VBIS= 1.51 +/- 0.21 and Kecn*t/VKecn= 1.52 +/- 0.18. CONCLUSION: The single-pool Kt/V calculated using the ionic dialysance method agreed with the conventional blood sample method provided that V was calculated using BIS or urea kinetics. V by either method was reproducible and varied little in an individual patient. Monthly determination of V allows determination of Kt/V for each dialysis session by ionic dialysance.

Adult↗

PubMed2003

Voxel-guided morphometry ("VGM") and application to stroke.

Monitoring of cerebral diseases associated with a change of morphology (e.g., stroke) requires unprecedented accuracy for quantification of its morphological progression for each voxel. The purpose of this paper is to provide a technique [voxel-guided morphometry (VGM)] to quantify macroscopic anatomical differences. VGM consists of four steps: 1) coarse linear alignment by the extended principle axes theory (ePAT) generalized to affine movements; 2) a cross-correlation-based technique using a matrix-norm for fine linear alignment; 3) the applied high-dimensional multiresolution full multigrid method determines the nonlinear deformations, thereby achieving a complete exploitation of information and effective processing. The method measures a gray-value-guided movement of each voxel from source to target. The resulting high-dimensional deformation field is further processed by 4) determination of volume alterations for each voxel. Furthermore, the effect of linear registration errors on final morphometric measurements is discussed and the conditions for a bijective correspondence of voxels assuming small alterations are derived. To illustrate the technique the changing morphology of different subjects suffering from cerebral infarction is presented by using commonly available T1-weighted magnetic resonance volumes. VGM visualizes that ischemic as well as remote regions are affected by stroke.

Algorithms↗