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Biomedical subjects

R Brunner

Publications and source records attributed to R Brunner.

At least 55 records · Page 3Linked to original sources
PubMed1998

Piezoelectrical shear-force distance control in near-field optical microscopy for biological applications.

We present a piezoelectrical shear-force distance control setup for scanning near-field optical microscopy. The setup is compact and tip exchange is easy. The topographical sensitivity is comparable to optical feedback systems. With an acceptable vibration amplitude of 5-10 nm we obtained a topographical resolution of 5 pm/square root of Hz. Because there is no laser necessary for tip position feedback, there is no extraneous light to interfere with spectroscopic and other low-light level experiments. Our technique permits measurements of soft biological samples in aqueous solution, which opens up many possible applications of near-field optical microscopy in biology and medicine.

Animals↗
PubMed1998

[Multi-flash ERG in cone dystrophies and cone-rod dystrophies].

BACKGROUND: Scotopic electroretinograms elicited with a multiple flash procedure were reported to be helpful in diagnosis of macular diseases. To evaluate the contribution of rods and cones to the recovery of light responses as recorded with this technique we performed a triple flash ERG procedure in patients with cone dystrophies and cone-rod dystrophies. MATERIALS AND METHODS: In 8 patients with cone dystrophy and 8 patients with cone-rod dystrophy and also in 18 healthy controls we recorded a standard ERG and the scotopic triple flash ERG with intensities between 0.01 and 0.2 cds/m2. Interflash intervals were adjusted at 140, 280, and 560 ms. Responses of the standard ERG were analysed as well as b-wave amplitudes at the short dark interval (140 ms) and the longer dark interval (280 ms). These responses were compared to responses after a long interflash interval (560 ms). Using a theoretical model parameters of b-wave recovery were determined and compared between the groups. RESULTS: In cone dystrophies responses of the scotopic triple flash ERG and the b-wave recovery parameters were normal whereas in combined dystrophies the triple flash responses were abnormal and the recovery data were pathologic. CONCLUSIONS: Cones did neither contribute to responses obtained with the multiple flash technique nor did they affect b-wave recovery as tested with this technique. Pathologic responses as described earlier with this technique in macular diseases could only be attributed to pathomechanisms globally affecting the rod system, e.g. dysfunction of retinal energy metabolism.

Adolescent↗
PubMed1998

Changes of hemorheological and biochemical parameters after plasma perfusion using a tryptophan-polyvinyl alcohol adsorber leading to clinical improvement in patients suffering from maculopathy.

BACKGROUND: Selective adsorption is an extracorporeal treatment able to reduce high-molecular-weight proteins and lipids. We evaluated its efficacy in lowering hemorheological parameters to achieve a better microcirculation of the retina. PATIENTS AND METHODS: Ten patients suffering from maculopathies of various origin underwent a selective plasma adsorption procedure using the TR-350. Plasma and whole blood viscosity, erythrocyte aggregation and proteins and lipids were determined before and 24 h after therapy. RESULTS: Selective adsorption therapy reduced the high-molecular-weight proteins and lipids. Plasma viscosity, standardized whole blood viscosity and erythrocyte aggregation were significantly lowered to 87, 88 and 65%, respectively, of their values prior to treatment. An improvement of visual acuity was achieved in 6/10 patients. Minor side effects were noted in 2/10 patients. CONCLUSIONS: Selective adsorption using the TR-350 adsorber is a safe technique, showing a high impact on blood rheology. The changes of hemorheological parameters led to clinical improvement in 6/10 patients suffering from retinal disorders.

Blood Viscosity↗
PubMed1998

Which procedure gives best results in reconstructing dislocated hip joints in cerebral palsy?

A retrospective study of the surgical repair of dislocated or subluxed hip joints in patients with spastic cerebral palsy was carried out to determine the procedure with the lowest recurrence rate. An open reduction and a corrective femoral osteotomy were combined with different pelvic osteotomies and different interventions on the iliopsoas muscle in most cases. The radiological results in 58 hip joints of 42 patients were assessed with a follow-up time of 5.9 years on average (2.8 to 11.0 years). Although some combined procedures were carried out in only an small number of cases, we can still draw some conclusions. The results were better, if a pelvic osteotomy and an intervention on the iliopsoas muscle were performed. An additional iliopsoas transfer made the hip joints more stable over the long term than lengthening. For severely deformed acetabula the Pemberton osteotomy was superior to the Chiari osteotomy. The Salter osteotomy was a good alternative in cases with mild subluxation. With some combined procedures the redislocation rate was as high as 66%, whereas the combination of an open reduction, a femoral osteotomy, an iliopsoas transfer and a Pemberton or Salter osteotomy gave a redislocation rate of only 11%. A concentric reduction of the hip joints was necessary. Primarily noncentered joints did not improve during the later course.

Acetabulum↗
PubMed1998

Conversion problems concerning automated mapping from ICD-10 to ICD-9.

The increasing parallel use of ICD-9 and ICD-10 complicates the comparability of coded diagnoses. This is the reason why we developed a symmetric table for interactive conversion between ICD-9 and ICD-10, based on a vector space text-retrieval method that resulted in unambiguous mapping from ICD-9 to ICD-10 in 64%, from ICD-10 to ICD-9 in 87% of all three- and four-character classes of the tabular list. Out of the remaining 13% of multi-valued relations, a table for automated mapping from ICD-10 to ICD-9 was created. In 9% of cases, the selection offered no problems. A compromise between preserving information content and maintaining the logical integrity had to be found in 2.4%; in 1.6% automated mapping was impossible because of newly defined concepts and structural differences between ICD-9 and ICD-10 that are not counterbalanced by a consistent system of residual categories. We recommend that in a future revision of the ICD, compatibility with the then existing classification system should be considered.

Diagnosis, Computer-Assisted↗
PubMed1998

[Psychotherapy aspects of inpatient treatment of adolescents with acute psychiatric illnesses].

In the inpatient treatment of acute psychiatric episodes in children and adolescents, the psychiatrist must set up an initial treatment plan incorporating one or more psychotherapeutic modalities and adapt this plan to the patient's clinical course. This article summarises the clinical experience of a model unit at the University of Heidelberg, the result of a collaboration between the Department of General Psychiatry and the Department of Child and Adolescent Psychiatry at the Clinic of Psychiatry. A series of 116 adolescent admissions was reviewed for clinical diagnosis, the nature and frequency of psychotherapeutic modalities, and the role of family involvement in patient care. Differential and adaptative approaches to the selection of treatment modalities in the context of an acute care setting are emphasised.

Acute Disease↗
PubMed1997

[Vitrectomy in treatment of eyes with complicated uveitis].

BACKGROUND: Vitrectomy serves as an important treatment modality in uveitis, removing inflamed vitreous body and eliminating secondary complications. The aim of our retrospective study was to evaluate the value of vitrectomy in the treatment of complications in uveitis. PATIENTS AND METHOD: We included 50 eyes of 50 patients suffering from chronic uveitis, which underwent vitrectomy surgery during the period of 1990 to 1993. The study only included patients who had vitrectomy for uveitis for the first time. Indications leading to surgery were density of optic media, retinal detachment, cyclitic or preretinal membranes. The mean follow-up was 455 (range 48-1420) days. RESULTS: Vitrectomy was performed at a mean delay of 452 days after initial presentation. The mean visual acuity at the time of surgery was 0.05. The best visual acuity postoperatively was measured at a mean time of 118 days after vitrectomy. Overall, at the last control, eyes with preoperative retinal detachment presented a much worse final functional result (visual acuity of 0.02) than eyes without detachment (visual acuity of 0.5). Ten eyes resulted in hypotonia after surgery (7 eyes with persisting hypotonia). Most frequent complications in the postoperative course were macular pucker (11 eyes), secondary glaucoma (10 eyes), macular edema (6 eyes) and retinal detachment (6 eyes). Fifty percent of all complications occurred within the first 3 months following surgery. CONCLUSION: Vitrectomy leads to a permanent increase in visual acuity through the treatment of complications, on the condition that a stable retinal situation was present preoperatively.

Adult↗
PubMed1997

Arthrogrypotic joint contracture at the knee and the foot: correction with a circular frame.

The purpose of this study was to investigate the efficacy of an external fixator (Ilizarov apparatus) for the treatment of severe joint contractures in patients with arthrogryposis multiplex congenita. Thirteen knees and 16 feet were treated in 13 patients at an average age of 11.9 years. The knee flexion contractures were corrected from 38.9 degrees preoperatively to a mean of 6.5 degrees postoperatively and to 17.3 degrees at follow-up (34 months). In the foot deformities, the equinus position was corrected from 29.7 degrees to 7.8 degrees on average. This external fixator is an efficient tool for correction of deformities in arthrogryposis.

Adolescent↗
PubMed1997

Morphology of the acetabulum in hip dislocations caused by cerebral palsy.

Twenty-four hip joints in 20 children with spastic cerebral palsy were assessed by standardised three-dimensional reconstructions from computed tomographic scans. All the hip joints showed a channel-like ebony deformity of the acetabulum along which the femoral bead had slid out, indicating a unidirectional instability. The channel was oriented along the longitudinal axis of the body within a sector of 25 degrees anteroposteriorly. In relation to the pelvis, the dislocation was directed more dorsally by 20 degrees as a result of a flexion contracture of the hip. The size of the femoral head corresponded with the size of the acetabulum in every case, even in long-standing dislocations.

Acetabulum↗
PubMed1997

Minimum alveolar concentration for halothane in children with cerebral palsy and severe mental retardation.

Children with cerebral palsy and severe mental retardation who present for operation may require lower concentrations of inhalational anaesthetics than healthy children. The minimum alveolar concentration (MAC) for halothane was measured in 36 children and adolescents, aged 4-18 years, who underwent orthopaedic surgery. The control group consisted of 12 healthy children (group 1). Children with cerebral palsy and severe mental retardation were allocated to one of two groups: those taking chronic anticonvulsant medication (group 2) (n = 12) and those who did not take any drugs (group 3) (n = 12). The mean (SEM) MAC value for halothane (expressed in volume per cent) was 0.90 (0.02) for healthy children. Children with cerebral palsy had significantly lower MAC values whether they took anticonvulsant drugs or not (0.62 (0.03) and 0.71 (0.10), respectively).

Adolescent↗
PubMed1997

Multidrug resistance-associated protein in acute myeloid leukemia: No impact on treatment outcome.

Drug resistance remains a major problem in the treatment of patients with acute myeloid leukemia (AML). Expression of the MDR1 gene in leukemic cells was shown previously to be associated with worse clinical outcome of the patients. The multidrug resistance-associated protein (MRP) has been shown recently to be another protein causing the multidrug resistance phenotype in cell lines, but its impact on clinical outcome in patients with AML remains to be proven. To determine the clinical significance of MRP in patients with de novo AML, we have studied the MRP expression in leukemic cells and its association with both response to induction chemotherapy and survival of the patients. MRP gene expression was determined by immuno-cytochemistry (n = 80) by means of the monoclonal antibodies QCRL-1 and QCRL-3. MRP expression was low, intermediate, and high in 19, 55, and 26% of the patients, respectively. High MRP expression was independent of age and sex of the patients, WBC count, and percentage of blasts. However, high MRP expression was more frequent in the FAB M5 subtype as compared to the other subtypes. MRP expression had no impact on clinical outcome. The complete remission rates were 65, 68, and 63% for patients with low, intermediate, and high expression, respectively. Overall survival was also independent of MRP expression. In contrast, patients with P-glycoprotein-positive AML had lower complete remission rates and shorter durations of survival. These data indicate that MRP is expressed in patients with de novo AML but, in contrast to P-glycoprotein, does not predict for outcome of induction chemotherapy or survival.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1996

The triple flash electroretinogram and its significance in macular diseases. B-wave recovery as a diagnostic tool.

PURPOSE: The purpose of this study was to evaluate recovery data for the b-wave of the electroretinogram (ERG) elicited using multiple flash stimulation with increasing stimulus intervals in normal controls and in patients with macular diseases. The results will describe effects of age and macular disease and define indexes characterizing the recovery process. METHODS: Scotopic Ganzfeld flash ERGs were elicited using interstimulus intervals of 140, 280, and 560 ms. Relative b-waves were calculated as the ratio b140 ms/b560 ms and b280 ms/b560 ms, respectively. Responses obtained in 134 eyes of 134 normal controls served as reference data. Fifty-four patients with different macular diseases were also examined and their data compared to the reference data. RESULTS: Relative b-wave amplitudes correlated with interstimulus interval and with flash luminance, but not with age. All patients had a normal ERG when recorded following the standard of clinical electroretinography. A sigmoidal model was suggested, providing three indexes characterizing the b-wave recovery process. Relative b-waves and recovery indexes varied in age-related macular degeneration, central serous retinopathy, vitelliform macular degeneration, Stargardt's disease, and pattern dystrophy. CONCLUSION: The triple flash ERG reflects energy-yielding and -utilizing mechanisms. It proved to be more sensitive in detecting functional lesions in macular diseases than the standardized explorating procedure. The b-wave recovery model allows differentiation between two independent mechanisms contributing to the b-wave recovery process. One or more of the three characterizing indexes are affected in different macular diseases.

Adolescent↗
PubMed1996

[Effects of fluorescein and indocyanine green angiography on subsequent dark adaptation and the electroretinogram].

BACKGROUND: In clinical practice the electroretinogram (ERG) usually should not be recorded immediately after conventional fluorescein angiography (FLA), because of the bleaching effects of strong light exposure on the course of dark adaptation and on the ERG. Currently it is not known, if indocyaningreen (ICG) angiography using the Heidelberg Retina Angiograph (HRA) has similar effects on the outer retina and if therefore the ERG should also not be recorded after ICG angiography. METHODS: Eight patients with different retinal diseases were examined. After 5 minutes of light adaptation to 160 cd/m2, Ganzfeld ERGs were repeatedly recorded using DTL electrodes during a 30 minutes dark period with a flash luminance of 0.1 cds/.m2. After this dark adaptation period a standardized ERG was recorded according to the ISCEV recommendations. This procedure was followed either by ICG angiography using the HRA or by conventional fluorescein angiography using the Canon CF 60 fundus camera. Within an interval of 5 minutes the above mentioned ERG procedure was repeated. RESULTS: ICG angiography using the HRA did neither affect the course of dark adaptation as measured by increasing b-wave amplitudes during the 30 minutes dark adaptation period, nor the values for each response of the Ganzfeld standard ERG. FLA did neither affect b-wave responses to dim stimuli, nor to stronger stimuli in the scotopic range. However, the course of dark adaptation was significantly prolonged after FLA. The maximum b-wave was not affected. CONCLUSIONS: ICG angiography using the HRA could be performed prior to the recording of the ERG, without any effect on the ERG. In contrast conventional FLA must be performed after ERG recordings, in order not to alter the electrophysiological responses.

Adult↗
PubMed1996

Inaccuracy of the migration percentage and center-edge angle in predicting femoral head displacement in cerebral palsy.

Six patients (seven hips) with total-body-involvement cerebral palsy were assessed for a hip reconstruction. Four patients (five hips) underwent three-dimensional computerized tomographic (3D CT) scans, and in two patients, faux profile views were obtained. The femoral head was subluxed or dislocated anteriorly in all seven hips. The migration percentage (MP) and center-edge angle (CEA) underestimated the pathology. We conclude that the MP and CEA do not exclude an anterior displacement of the femoral head and calls into question the accuracy of methods relying on two-dimensional imaging in assessing hip containment in this group of patients. The faux profile view is sufficient to show an anterior hip displacement but a 3D CT gives superior detail to help in planning a surgical reconstruction.

Cerebral Palsy↗
PubMed1996

Clinical efficacy of haemorheological treatment using plasma exchange, selective adsorption and membrane differential filtration in maculopathy, retinal vein occlusion and uveal effusion syndrome.

The aim of the study was to test the clinical efficacy of haemorheological treatment with extracorporeal techniques in ocular diseases. We treated patients suffering from maculopathies of different origin: age-related (AMD, n = 17), uveitis-associated (n = 14) and myopia-associated maculopathy (n = 5). We also treated patients with uveal effusion syndrome (n = 3) and central retinal vein occlusion (n = 4) resistant to haemodilution or steroid therapy. The treatment consisted of plasma exchange, selective adsorption with a tryptophan-polyvinylalcohol adsorber and membrane differential filtration. Maculopathy patients underwent two treatments while the other patients received between 1 and 7 treatments. Pulsatile ocular blood flow was measured in 10 patients before and after therapy. The main parameter for evaluating clinical outcome was the change in visual acuity. Severe side-effects did not occur. The rheological parameters including plasma viscosity, whole blood viscosity and erythrocyte aggregation were statistically significantly lowered. Of 36 patients suffering from maculopathy, 25 showed an improvement of at least 1 line of visual acuity after therapy, 7/17 patients in AMD, 6/14 in uveitis and 0/5 in myopia improved 3 lines or more. All patients suffering from retinal vein occlusion improved at least 1 line and two showed an improvement of 3 lines or more. In uveal effusion syndrome, an improvement of 3 lines or more was reached in all patients. Plasma exchange, selective adsorption and membrane differential filtration are effective rheological treatment approaches to improving visual acuity in patients suffering from maculopathy except myopia-associated maculopathy. Efficacy in patients suffering from central retinal vein occlusion and uveal effusion syndrome was proven, even when the patients were resistant to previous haemodilution or steroid therapy. We conclude that a rheological approach should be considered before invasive methods such as laser coagulation, radiation therapy or surgery are applied.

Hemofiltration↗
PubMed1996

Changes of haemorheological parameters when using plasma exchange, selective adsorption and membrane differential separation.

At present, conventional haemorheotherapy consists of changes in life-style, drug therapy and haemodilution. Extracorporeal therapy has been considered only for the treatment of hyperviscosity syndromes. However, a wide range of viscosity-related syndromes may be amenable to rheological therapy if appropriate techniques were available. According to our data, plasma exchange, selective adsorption and membrane differential filtration may lead to an improvement of haemorheology and clinical conditions. For reasons of economy and feasability, membrane differential filtration is favoured over other techniques of differential separation therapy.

Blood Viscosity↗
PubMed1996

Pathological fractures in patients with cerebral palsy.

A retrospective study was made of 37 patients with 54 fractures that occurred without significant trauma. The morbidity and causes of these pathological fractures in patients with cerebral palsy were analyzed. The major causes for the fractures were long and fragile lever arms and stiffness in major joints, particularly the hips and knees. An additional factor was severe osteoporosis following a long period of postoperative immobilization. Seventy-four percent of the fractures occurred in the femoral shaft and supracondylar region. Stress fractures were rare (7%) and involved only the patella. Conservative treatment was sufficient in most cases but surgical fixation provided a good alternative for fractures of the femoral shaft. Intraarticular fractures with joint incongruity resulted in a decreased level of activity of the patient. Since osteoporosis is a major risk factor, patients with cerebral palsy should bear weight to prevent pathological fractures. Any stiffness of major joints and extended periods of immobilization should be avoided.

Adolescent↗