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Biomedical subjects

G Brandt

Publications and source records attributed to G Brandt.

At least 19 recordsLinked to original sources
PubMed1999

CRIGOS: a compact robot for image-guided orthopedic surgery.

The CRIGOS (compact robot for image-guided orthopedic surgery) project was set up for the development of a compact surgical robot system for image-guided orthopedic surgery based on user requirements. The modular system comprises a compact parallel robot and a software system for planning of the surgical interventions and for supervision of the robotic device. Because it is not sufficient to consider only technical aspects in order to improve in clinical routine the therapeutic outcome of conventional interventions, a user-centered and task-oriented design process has been developed which also takes human factors into account. The design process for the CRIGOS system was started from requirement analysis of various orthopedic interventions using information gathered from literature, questionnaires, and workshops with domain experts. This resulted in identification of conventional interventions for which the robotic system would improve the medical and procedural quality. A system design concept has been elaborated which includes definitions of components, functionalities, and interfaces. Approaches to the acquisition of calibrated X-rays will be presented in the paper together with design and evaluation of a first human-computer interface. Finally, the first labtype parallel robot based on low-cost standard components is presented together with the first evaluation results concerning positioning accuracy.

Humans↗
PubMed1998

Sensitivity, specificity and predictive value of modified assays for activated protein C resistance in children.

Very little data is available assessing the clinical utility of coagulation-based APC resistance assays compared to DNA-based analysis for the factor V Leiden mutation in children. Therefore, the clinical utility of four aPTT-based assays for APC resistance was evaluated in 169 children, ages 3 months through 16 years. The prevalence of the Arg506 to Gln mutation was 7/169 (4.1%). Using cutoff points derived from the normal PCR-screened population (n = 162), two assays for APC resistance (APC-SR and n-APC-SR) gave poor concordance with the PCR assay (sensitivity 29% and 57%, respectively). Two modified assays (FDAPC-SR and n-FDAPC-SR), in which patient plasma was prediluted 1:5 in factor V deficient plasma, gave excellent concordance (sensitivity 100%). The predictive value of a positive test was 0.25, 0.44, 1.00 and 0.88 for the APC-SR, n-APC-SR, FDAPC-SR and n-FDAPC-SR, respectively. The FDAPC-SR and n-FDAPC-SR tests gave excellent discrimination using cutoff values derived from the total population (n = 169) without regard to previous PCR screening results.

Adolescent↗
PubMed1997

Enantioselective high-performance liquid chromatography assay of (+)R- and (-)S-alpha-lipoic acid in human plasma.

A specific plasma level assay for the enantiomers of alpha-lipoic acid is described. It makes use of liquid-liquid extraction, chemical reduction to the dithiol enantiomers, and their precolumn chiral derivatisation with o-phthalaldehyde in the presence of D-phenylalanine. The two diastereomeric derivatives are separated by reversed-phase HPLC with fluorescence detection. The working range of the assay is between 15 ng/ml (lower limit of quantitation) and 1,000 ng/ml for either enantiomer.

Calibration↗
PubMed1997

Resistance to activated protein C and Legg-Perthes disease.

Thrombophilia may cause thrombotic venous occlusion in the femoral head, with venous hypertension and hypoxic bone death, leading to Legg-Perthes disease. Resistance to activated protein C, the most common thrombophilic trait, was measured in 64 children with Legg-Perthes disease. Genomic deoxyribonucleic acid was studied to delineate the CGA-->CAA substitution at position 1691 of the Factor V Leiden gene responsible for resistance to activated protein C. The activated protein C ratio was calculated by dividing clotting time obtained with activated protein C-calcium chloride by clotting time obtained with calcium chloride alone. Resistance to activated protein C, with a low activated protein C ratio (less than 2.19, the 5th percentile for 160 normal pediatric controls) was the most common coagulation defect, found in 23 of 64 children with Legg-Perthes disease versus 7 of 160 pediatric controls. Eight of 64 children with Legg-Perthes disease had a low activated protein C ratio and the mutant Factor V gene (7 heterozygotes, 1 homozygote) versus 1 of 101 normal pediatric controls. Two or 3 generation vertical and horizontal transmission of heterozygosity for the mutant Factor V gene was found in 4 of the 8 kindreds. Of 64 children with Legg-Perthes disease, only 14 (22%) had entirely normal coagulation measures. Resistance to activated protein C appears to be a pathogenetic cause of Legg-Perthes disease.

Blood Coagulation Disorders↗
PubMed1993

The efficacy and safety of a continuous albuterol protocol for the treatment of acute adult asthma attacks.

We performed a prospective study over a 6-month period to test the efficacy and safety of a continuous nebulized albuterol protocol for the treatment of acute adult asthma attacks. All patients 18 years or older presenting to the emergency department with acute asthma attacks were begun by the triage nurse on the protocol of three continuous albuterol (2.5 mg) nebulizer treatments. Pretreatment and posttreatment peak flow, respiratory rate, pulse, and blood pressure were documented and patients gave a pretreatment and posttreatment rating of the clinical severity of their attack using a (1 to 10) visual analog scale. In addition, all adverse effects were noted. Seventy-six patients were entered in the study. The average age was 44 years (range, 20 to 82 years). Pretreatment and posttreatment peak flow, respiratory rate, pulse, blood pressure, and clinical severity were compared using the paired t test. Patients showed statistically significant increases in peak flow (128 to 292; P < .0001) and statistically significant decreases in respiratory rate (27 to 20; P < .0001); pulse, 103 to 94 (P < .0001); clinical severity, 7.8/10 to 1.8/10 (P < .0001); and blood pressure, 141/82 to 132/77 (P < .001). Adverse effects were minimal. Two patients (2.6%) felt flushed, three patients (4%) felt jittery, and one patient (1.3%) had a sensation of palpitations. We conclude that a continuous nebulized albuterol protocol is both extremely efficacious and safe for the treatment of acute adult asthma attacks.

Acute Disease↗
PubMed1990

Cytogenetic investigations on a cell line derived from a carcinoma arising in a salivary gland pleomorphic adenoma.

This article discusses the results of cytogenetic investigations of a cell line derived from a malignant tumor arising in a benign salivary gland pleomorphic adenoma. Initial karyotypic studies became possible with cells of the second in vitro passage and revealed the existence of hypertetraploidy. Furthermore, a marked polysomy 7 and a translocation involving 12q13-15, a breakpoint also frequently seen in benign pleomorphic adenomas, were noteworthy. During long term culture, the number of chromosomes per cell decreased as well as the number of copies of chromosome 7. Cell tumorigenicity was proved by heterotransplantation to nude mice. The resulting tumors were karyotyped again. No significant changes of the chromosome number or of the degree of polysomy 7 were found compared to the cells before heterotransplantation. In contrast, the cells from the nude mice tumors showed a remarkable number of different isochromosomes probably indicating an unknown factor supporting the generation of isochromosomes. The consistent presence of the t(12;?)(q13-15;?) makes the cell line well suited for molecular studies of this breakpoint region.

Adenoma, Pleomorphic↗
PubMed1989

Relationship of cytogenetic subtypes of salivary gland pleomorphic adenomas with patient age and histologic type.

Sixty-nine salivary gland pleomorphic adenomas were fully karyotyped by G-banding including 40 tumors previously reported. The cytogenetic results allowed to distinguish between three major chromosomal subgroups characterized by either an apparently normal karyotype or by rearrangements of chromosome 8q12 or by rearrangements of chromosome 12q14-15. Significant correlations of these karyotypic groups with the age of the patients and histologic subgroups of the pleomorphic adenomas were found. Furthermore, our analysis revealed that the three main cytogenetic subgroups showed an uneven geographical distribution. Based on these results we have concluded that the cytogenetic groups represent different etiologic entities.

Adenoma↗
PubMed1989

[Secretory breast cancer. A special morphologic entity, especially in children and young females].

We are reporting a rare case of secretory breast cancer with axillary node involvement in a 16-year-old patient. Symptomatic systemic spread occured unusually early during adjuvant chemotherapy, suggesting primary resistance of the tumour to chemotherapy. We are unaware of any such case reports published world wide. Due to the small number of similar case reports in the literature, the natural history of this type of cancer remains uncertain, offering no development of firm treatment guidelines.

Adolescent↗
PubMed1988

[Metastasis of cancer of the external ear].

Follow-up of 103 patients with squamous cell carcinomas of the auricula showed that 20 of them developed regional lymph node metastases. The effect of size, site and certain histological parameters on the occurrence of metastases was assessed. The incidence of metastases correlated with increasing size of the tumour.

Aged↗
PubMed1987

In-vitro studies of antibiotic combinations for multiply-resistant coagulase-negative staphylococci.

Coagulase-negative staphylococci are being implicated as pathogens with increasing frequency and this may in part be due to their development of resistance to a wide variety of antibiotics. Because vancomycin is the only drug generally available for treating these multiply resistant organisms, we have tested several combinations of antibiotics for activity in vitro against these organisms. These in-vitro studies suggested that rifampicin combined with either gentamicin or cefamandole might occasionally provide an efficacious alternative to vancomycin, while the novobiocin plus rifampicin combination might be an effective oral regimen against methicillin-resistant coagulase negative staphylococci. Resistance to co-trimoxazole was found in nearly all isolates tested.

Anti-Bacterial Agents↗
PubMed1986

[Intrahepatic bile duct cysts].

Because of the risk of carcinoma, choledochal cysts always should be completely removed. If the cyst is extrahepatic, this should not offer any problem. Radical excision of an intrahepatic cyst, however, can present as a major problem and is in fact not always achievable. The anatomical situation (involvement of both lobes of the liver) or the general condition of a patient can force us to limit the surgical procedure. We report our experience with 5 cases of intrahepatic choledochal cyst, emphasizing the difficulties of achieving the before mentioned therapeutic goal. Details on today's pathogenetic theories and classification of choledochal cysts are reported from the literature.

Aged↗
PubMed1985

MR imaging using specialized coils.

The purpose of this study was to evaluate the clinical utility of specialized coils with magnetic resonance (MR) imaging and to determine the potential improvement in the signal-to-noise ratio (SNR) provided by the various coils. A total of 48 patients were studied-33 with surface coils and 15 with limb coils. MR imaging was performed with a superconducting magnet operating at 0.35 T. Two applications of surface coils were evaluated; one used for both transmitting and receiving and the other used only for receiving. Structures studied with the surface coils included the orbit, carotid artery, cervical and lumbar spine, parotid and thyroid glands, other neck structures, femoral artery, kidney, prostate, hip, and heart. The regions studied with the limb coil were the ankle, knee, wrist, elbow and popliteal artery. We calculated the SNR, and the results demonstrated a marked improvement with the specialized coils: a twofold increase for the 10-cm surface coil versus the head coil and a 4.6-fold increase compared with the body coil, a 2.3-fold increase for the 20-cm surface coil compared with the body coil, and 2.8- and 6.4-fold increases for the limb coil versus the head coil and the body coil, respectively. The use of specialized coils was feasible in the clinical setting and they provided a marked improvement in the image SNR, which facilitated the imaging of small and superficial structures.

Adolescent↗
PubMed1984

[Blood vessels of the human caudal pancreatic segment].

The segmental pancreatic allograft transplantation is effective in the treatment of diabetes mellitus and a technically simple operation, but it may bring about many complications. Important for a normally transplantation function is its adequate blood supply. The arterial and venous system in 60 human caudal pancreatic segments are examined with angiographic. 4 different arterial types of supply and the differences in the arterial and venous system are described. All pancreatic segments would have been appropriated for transplantation.

Angiography↗