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Biomedical subjects

M Schuster

Publications and source records attributed to M Schuster.

At least 37 records · Page 2Linked to original sources
PubMed2004

[Does patient satisfaction correlate with pain level during patient-monitored epidural analgesia. Evaluation of data from postoperative pain service].

INTRODUCTION: The evaluation of patients' satisfaction and outcome after surgery is of increasing importance. An optimized postoperative pain management may contribute substantially to this important goal. METHODS: After approval of the local ethics committee and written informed consent, 150 adult patients receiving epidural catheters for postoperative pain management were evaluated over 1 week postoperatively with respect to their satisfaction with the pain therapy and incidence of side effects. All patients received a continuous epidural infusion with ropivacaine 0.2% plus sufentanil 0.5 microg/ml via a PCEA pump (basal rate 6-8 ml/h, bolus 2 ml, lockout time 5 min). For assessment of pain the VAS scale (0-100 mm) was used, and patients' satisfaction was evaluated using a numeric rating scale (1-6, 1=very good, 6=very dissatisfied). RESULTS: Of the patients, 95 were operated in general surgery, 32 in orthopedics, and 23 in gynecology. Time of treatment with epidural catheters (71% thoracic, 29% lumbar catheters) was 5.1 +/- 2.9 days. Of the patients, 87.8% evaluated the postoperative pain service as very good or good, and 89% of the patients would choose the same pain therapy again. Side effects mainly consisted in bladder dysfunction (19%) and intermittent motor blockade (18%) especially with lumbar catheters. Correlation between patient satisfaction and the remembered maximum pain levels was low ( r=0.266). CONCLUSION: Evaluation of patients' satisfaction with postoperative epidural pain therapy resulted in a high degree of satisfaction without correlation between patients' satisfaction and recalled maximum pain levels. These results, including side effects and special problems during pain therapy, provide motivation to further improve postoperative pain management.

Anesthesia, Epidural↗
PubMed2004

A new fast and large area neutron detector using a novel image plate readout technique.

At Agfa Medical Imaging Systems, a new type of image plate scanner is being developed. Instead of scanning the irradiated image plate with a single laser and reading the luminescence information with a single light collector and photomultiplier, the new system employs a whole line of laser diodes and a set of CCD line sensors. This technique allows for virtually unlimited detection areas and a very fast readout.

Diagnostic Imaging↗
PubMed2003

[Social orientation of parents of children with cleft lip and palate].

BACKGROUND: Cleft lip and palate are the most common malformation in the orofacial region. The type and dimension of the cleft determine the functional limitations of respiration, swallowing, speech, articulation and hearing. In addition, cosmetic and communicative restrictions influence the cognitive, social and educational progress and the wellbeing of the children affected. Their parents face a difficult and lasting task: They have to cope with their child's handicap and the current standardised treatment procedures which start in early infancy. To guarantee optimum therapeutic success parents must be included as co-therapists. Therefore more information about parents' concerns and coping strategies are required. METHOD: To assess the strain put on parents of children with cleft lip and palate as well as the parents' coping strategies, a standardised questionnaire for the German-speaking parents was used during consultation in the out-patient clinic. RESULTS. In comparison with parents of children with other handicaps, the parents of children with cleft lip and palate feel less stressed out and adopt strategies of coping such as intensification of partnership, use of social support, as well as self-respect and fulfillment. Working mothers are less preoccupied and less at risk of being focussed on the handicapped child only. In comparison, the parents of children with Orofacial clefts focus less on the handicapped child in general than those parents whose children suffer from additional behavioural disorders. DISCUSSION: Though several functional, behavioural and psychological disorders may occur in children with cleft lip and palate their parents feel comparatively little stress. They do use a variety of coping strategies and tend to adopt a rather positive approach. Certainly, additional disorders of the child lead to more parental stress and likewise requiring more attention to the child which may even accentuate existing behavioural disorders. CONCLUSION: Parents of children with cleft lip and palate experience less stress in comparison with parents of children with other handicaps. Therapeutic efforts and regular check of the child's progress might support parents' coping strategies. Therapists should also ask for additional disorders such as behavioural disorders and initiate adequate support.

Adaptation, Psychological↗
PubMed2003

[Coping strategies in laryngectomy patients].

BACKGROUND: Over the last few years, paradigms for judging the results of treatment of tumor patients have shifted. In addition to characteristics such as the complete excision of the tumor and the duration of patient survival, restoring the quality of life has become an equally important aim. There is still a lack of systematic (and sufficient) research on coping strategies as a means of dealing with malignant tumors of the head and neck. PATIENTS AND METHOD: In a cross-sectional study, 25 laryngectomees, whose voices had been successfully restored with a Provox voice prosthesis,were examined for their coping strategies and the effects of the illness on their lives. The standardized Trier Scales of Coping Strategies and a custom-made questionnaire, which helped to structure the anamnesis of disease specific functional restrictions and the state of rehabilitation, were used as the means of inquiry. RESULTS: A high percentage of patients were content despite objective and subjective restrictions. Voice replacement was mainly experienced as unproblematic,with psychosocial restraints more commonly being felt in connection with pain and difficulties ingesting food. A correlation between the patients' evaluation of physical,psychological and social experiences and the coping strategies applied could not be verified. The way laryngectomees deal with their illness does not differ from the strategies of patients suffering from malignant or chronic diseases of other organ systems. CONCLUSION: The Trier Scales of Coping Strategies is a suitable means for determining the coping strategies of laryngectomees who have been successfully rehabilitated with the help of voice prostheses. The patients examined here did not apply different coping strategies from groups of patients with other severe illnesses. Obviously, the limitations on communication do not constitute a determining factor in coping with the disease. This finding is useful when planning psychological and social rehabilitation, e.g. by psychosomatic interventions.

Adaptation, Psychological↗
PubMed2003

[Nutrient composition of the muscle, fat, and bone tissue of carcasses during the development of lambs of the merino breed with different feeding intensities].

In a developmental study of lambs, the following question was investigated: What is the influence of gender, bodyweight, and feeding intensity on the nutritional value of the carcass as well as the body tissues? This study was conducted with 108 lambs (50% males and 50% females) of the merino breed. The animals were fattened according to three feeding intensity levels ("high","medium", and "low") using varied feed concentrates and hay in their daily rations. They were slaughtered at body weights of 30, 45 or 55 kg. Six male and six female lambs were slaughtered at a bodyweight of 18 kg which was the initial weight of the fattening lambs. The left half of the slaughtered animal was carved according to the guidelines provided by the DLG (German Agricultural Society). For each cut, an examination of the meat(muscle), fatty tissue and bone/tendons was carried out and the percentages of these tissue components were determined for the whole joint. The samples of the tissues as well as the cuts were analysed for dry matter, crude protein, total fat level and crude ash. The carcasses of the male lambs showed higher protein content and lower fat levels. With increasing feeding intensity level and bodyweight, the differences in these nutritional components between the sexes rose. The muscle tissue (meat) of the lamb carcasses at the usual slaughter weight of 45 kg showed relatively low fat content (less than 10%). This was especially noticeable in carcasses of male lambs (less than 8%).

Adipose Tissue↗
PubMed2003

[Guidelines and their practical application in congenital hearing loss].

BACKGROUND: Permanent congenital hearing loss in children does not only influence speech acquisition but also has a severe impact on the entire intellectual and psychological development, and thus social integration is handicapped. However, at least partial compensation can be achieved by complex rehabilitative measures. One of the first medical therapies in children with congenital hearing loss is to equip them with hearing aids. As part of quality management the purpose of this study is to discuss pedaudiological aspects and results of hearing - impaired children equipped with hearing aids against the background of guidelines from Germany and the US. METHODS: Data of 107 children equipped with hearing aids from 1997 to 1999 were analysed referring to the relevant German and US guideline. RESULTS: In 53 girls and 54 boys, 45% were suffering from at least severe, 45% from moderate and 10% from mild hearing loss. 93 children presented sensory hearing loss, 8 combined and 2 conductive hearing loss. 2 children had unilateral hearing loss, one a combined on one ear and a sensory hearing loss on the other and one child had a central auditory processing disorder. The age when the hearing loss was diagnosed depended on its grade and correlated with adverse environmental aspects. 34 children suffered from a syndrome or multiple handicaps, in these cases, the hearing loss was diagnosed at a later date than in children suffering from hearing loss only. In cases with near deafness audiological results with hearing aids were not sufficient; in these cases, cochlea implantation had to be discussed as an alternative measure. CONCLUSION: The data obtained from this study underline the need for universal hearing screening. Discussing the data against the relevant German and US guidelines clearly shows that German benchmarks are not as strict as the American ones. This has to be taken into account for further guideline development in Germany. As permanent hearing loss in children with syndromes and multiple handicaps and children with adverse environment is diagnosed at a later date than in other children public, measures have to be taken to improve this situation.

Adolescent↗
PubMed2003

The laryngectomee substitute voice: image processing of endoscopic recordings by fusion with acoustic signals.

OBJECTIVES: The most radical cancer therapy of the throat is the total excision of the larynx which post-operatively results in the loss of voice. A widely-used method of voice rehabilitation is the insertion of a silicone valve, which establishes an unidirectional connection between trachea and esophagus. Thus, during exhalation, air can be directed from the trachea into the esophagus. This air stream excites tissue vibrations of the esophagus and the hypo-pharynx which act as a substitute voice generator. Purpose of the current study is to present a technique for visualizing the dynamics of the substitute voice generating element. METHODS: Digital high speed videos of the vibrating tissue are simultaneously recorded with the emitted acoustic signal. The high speed sequences are directly evaluated by a three-step knowledge based algorithm. It considers correlation between image and acoustic data, information about the gray value of each pixel, and continuity of tissue vibration. The temporal properties of an image series are investigated by evaluating the time dependent gray value at each pixel position. RESULTS: The applicability of the algorithm is exemplarily demonstrated using the data of one male patient. It enables the identification of the regions within an image series which are mainly responsible for the acoustic signal. Additionally, the dynamics of tissue vibrations are visualized. The main propagation direction can be clearly identified. CONCLUSIONS: The new methodology summarizes the information about endoscopic and acoustic recordings of substitute voice into a single image. The results allow a first estimation of tissue velocity and elastic properties of oscillating tissue.

Algorithms↗
PubMed2002

Expression and purification of homogenous proteins in Saccharomyces cerevisiae based on ubiquitin-FLAG fusion.

The construction of an expression vector for increased expression of cytoplasmic proteins in Saccharomyces cerevisiae is described. To enhance the yield of expressed proteins, fusion of ubiquitin to an octapeptide (a FLAG tag) upstream of the respective model genes was applied. During protein maturation ubiquitin is efficiently removed by yeast autologous hydrolases, generating the FLAG octapeptide at the N-terminus. Fusion proteins were recognized by the specific monoclonal antibody M1 directed against the FLAG tag. The FLAG-tagged proteins were purified to homogeneity by immunoaffinity chromatography using an anti-FLAG M1 agarose. Different model proteins, green fluorescent protein, green fluorescent protein-human lysozyme, green fluorescent protein elongation-initiahon factor 5a, green fluorescent protein-rapamycin-selective 25-kDa immunophilin, and green fluorescent protein-heat shock protein 90 beta have been selected to demonstrate the efficiency of the new vector construct.

Antibodies, Monoclonal↗
PubMed2002

[Influence of positioning on the quality of unilateral spinal anesthesia].

OBJECTIVE: Unilateral spinal anaesthesia ("hemi-spinal") is theoretically associated with the advantages of fewer cardiovascular effects and longer duration of action while offering high density motor block of the extremity affected. METHODS: In a prospective, randomised study 60 patients received 2 mls of 4 % hyperbaric mepivacaine intrathecally. Group I (n = 30) was returned into the supine position after 5 minutes in the lateral position, Group II (n = 30) was kept in the lateral position for 15 minutes. Spread and subsequently offset of sensory and motor block were assessed separately for each side at predetermined time intervals pre-, intra-, and postoperatively. RESULTS: Both groups were identical regarding their morphometric parameters. In Group I (5 minutes), the mean cephalad spread of sensory block of the initially dependent side was T6 after 15 mins and T4 after 25 mins. On the initially non-dependent side, the sensory block reached to T5 after 25 mins. In Group II (15 mins), the initial mean difference was equivalent to two segments (T7/T9). After 25 minutes there was no difference to the results in Group I. CONCLUSIONS: Unilateral spinal anaesthesia ("hemi-spinal") is an attractive concept, supposed to be associated with the above mentioned advantages and the additional benefit of a partially maintained sensation of one limb. The results demonstrated in this study seriously question this theoretical concept. The most likely reason for the lack of inter-lateral differences in sensory block is the high concentration of hyperbaric local anaesthetic in the cerebrospinal fluid on the dependent side, which, on turning the patient to the supine position, will transit to the previously non-dependent side subsequently leading to a significant block.

Anesthesia, Spinal↗
PubMed2001

Observation of breather resonances in Josephson ladders.

We report experimental observation of resonances excited by nonlinear localized states (rotobreathers) in Josephson junction ladders. The rotobreathers are found to persist in a frequency range that allows for their resonant interaction with linear electromagnetic modes in the ladders. This interaction leads to nearly constant voltage steps on the current-voltage characteristics. We also present numerical simulations that agree well with experimental data and confirm the resonant interaction between breathers and linear waves. Resonances occur at the base frequency as well as higher harmonics of the linear modes. The observed substructures on the resonances are attributed to the cavity modes for the ladders. Both experimental and simulated current-voltage characteristics show good quantitative agreement with an analytically calculated dispersion relation for linear electromagnetic modes.

Journal Article↗
PubMed2001

Increased prevalence of autoimmune phenomena and greater risk for alloreactivity in female heart transplant recipients.

BACKGROUND: The influence of sex on alloreactivity and graft outcome after heart transplantation was evaluated. METHODS AND RESULTS: A retrospective review of 520 consecutive recipients of a primary cardiac allograft between 1992 and 2000 at a single center was performed. The influence of sex on alloreactivity, acute rejection, transplant-related coronary artery disease, and survival was determined. Statistical methods included logistic regression analysis and Kaplan-Meier actuarial survival analysis. Female recipients had an increased prevalence before transplant of idiopathic cardiomyopathy, antinuclear antibodies, and HLA-B8, DR3 haplotypes. After transplant, female sex predicted shorter duration to a first rejection, higher cumulative rejection frequency, and earlier posttransplant production of anti-HLA antibodies. Female recipients had higher early mortality rates (<6 months) that were due to infection. Fatal infections correlated with 2-fold higher cyclosporine levels in female recipients. However, the incidence of transplant-related coronary artery disease developing beyond 1 year after transplant was lower in female than in male recipients. CONCLUSIONS: Females undergoing cardiac transplantation are more likely to manifest features of an underlying autoimmune state. This may predispose to a higher posttransplant risk of allograft rejection and requirement for increased immunosuppression. Earlier diagnosis and management of alloreactivity in female recipients before development of acute rejection and the use of more focused and less globally immunosuppressive agents during established rejections may have a significant effect on the clinical outcome of female cardiac allograft recipients.

Autoantibodies↗
PubMed2001

Inhibition of fucosyltransferase V by a GDP-Azasugar.

A GDP-azasugar conjugate was synthesized starting from an enzymatically obtained phosphorylated azasugar. It inhibits human fucosyltransferase V at micromolar concentrations, which is discussed in terms of transition state analogy.

Binding Sites↗
PubMed2001

Conformational coupling in the chemotaxis response regulator CheY.

CheY, a response regulator protein in bacterial chemotaxis, serves as a prototype for the analysis of response regulator function in two-component signal transduction. Phosphorylation of a conserved aspartate at the active site mediates a conformational change at a distal signaling surface that modulates interactions with the flagellar motor component FliM, the sensor kinase CheA, and the phosphatase CheZ. The objective of this study was to probe the conformational coupling between the phosphorylation site and the signaling surface of CheY in the reverse direction by quantifying phosphorylation activity in the presence and absence of peptides of CheA, CheZ, and FliM that specifically interact with CheY. Binding of these peptides dramatically impacted autophosphorylation of CheY by small molecule phosphodonors, which is indicative of reverse signal propagation in CheY. Autodephosphorylation and substrate affinity, however, were not significantly affected. Kinetic characterization of several CheY mutants suggested that conserved residues Thr-87, Tyr-106, and Lys-109, implicated in the activation mechanism, are not essential for conformational coupling. These findings provide structural and conceptual insights into the mechanism of CheY activation. Our results are consistent with a multistate thermodynamic model of response regulator activation.

Amino Acid Sequence↗
PubMed2001

Infectious complications the year after autologous bone marrow transplantation or peripheral stem cell transplantation for treatment of breast cancer.

Few studies have examined the specific incidence of infections after autologous bone marrow transplantation (BMT) or peripheral stem cell transplantation (PSCT) for treatment of breast cancer. We reviewed the medical records of 127 consecutive patients who underwent autologous BMT or PSCT for breast cancer at the University of Pennsylvania Medical Center from 1 May 1991 through 31 March 1995 and through 1 year of follow-up. The mean duration of neutropenia after transplantation was 10 days. Initial infections included catheter-site cellulitis (in 20 patients [16%]), bacteremia (17 [13%]), Clostridium difficile colitis (13 [10%]), and urinary tract infection (in 10 [8%]); there was only 1 documented invasive fungal infection (1% of patients). The mortality from infection was 2%. Infections during the 1 year follow-up included upper respiratory infections (11 patients [10%]) and dermatomal zoster (9 [8%]); neither was significantly associated with death. This group of patients who underwent BMT or PSCT for breast cancer had a low rate of infectious morbidity and mortality. Viral and fungal infections were rare despite inconsistent prophylaxis.

Adult↗
PubMed2001

Transmembrane-sequence-dependent overexpression and secretion of glycoproteins in Saccharomyces cerevisiae.

Protein expression using the secretory pathway in Saccharomyces cerevisiae can lead to high amounts of overexpressed and secreted proteins in culture supernatants in a short period of time. These post-translational modified expression products can be purified up to >90% in a single step. The overexpression and secretion of the transmembrane glycoprotein signaling lymphocytic activation molecule (SLAM) was studied. SLAM belongs to the immunoglobulin superfamily and its engagement results in T-cell expansion and INF-gamma production. The molecule is composed of an extracellular, a single-span transmembrane and a cytoplasmatic domain. The extracellular part may be relevant for stimulation studies in vitro since SLAM is a high-affinity self-ligand. Therefore several fragments of this region have been expressed as Flag-fusions in S. cerevisiae: a full-length fragment containing the transmembrane region and the autologous signal sequence, another without the transmembrane region, and two fragments without the autologous signal sequence with and without the transmembrane region. By molecular cloning, the different deletion mutants of the cDNA encoding the full-length construct have been inserted in a yeast episomal plasmid. Upstream of the cDNA, the alpha-leader sequence of a yeast mating pheromone has been cloned to direct the fusion proteins into the secretory protein maturation pathway. All four fragments were expressed but yield, location, and maturation were highly influenced by the transmembrane domain and the autologous signal sequence. Only the fragment without autologous signal sequence and transmembrane domain could be efficiently secreted. High-mannose glycosylation was analyzed by lectin mapping and digestion with specific glycosidases. After enzyme treatment, a single band product with the theoretical size could be detected and identified as SLAM by a specific monoclonal antibody. The fusion protein concentration in the supernatant was 30 microg/ml. The affinity-purified and deglycosylated protein is a tool for further biochemical and biophysical characterization of SLAM.

Animals↗
PubMed2001

Rapid exchange of large numbers of donor- and host leukocytes after human liver transplantation.

After liver transplantation, the release of donor leukocytes into the host and the uptake of host leukocytes by the graft is one of the earliest immunologic interactions between donor and host. Using three-color flow cytometry, these interactions were investigated in eight patients from 5 min-24 h after receiving HLA unmatched liver grafts. Five minutes after reperfusion, 5.0 % +/- 1.4 % of all blood leukocytes in the host were of donor origin, decreasing to 1.1 % +/- 0.8 % after 24 h. Donor granulocytes preferentially disappeared from the host circulation, whereas no differences were found between NK-cells and various B- and T cell subpopulations. Furthermore, host granulocytes were preferentially retained in the donor liver. Thus, despite extensive pre-operative perfusion, more than 10(9) donor leukocytes quickly leave the liver graft while host granulocytes preferentially accumulate there. A better understanding of the molecular mechanisms mediating these early interactions might help to develop new strategies for diagnosis and therapy of liver graft rejection.

Adult↗