Biomedical subjects

A Posch

Publications and source records attributed to A Posch.

26 records · Page 2Linked to original sources

PubMed1995

Interlaboratory reproducibility of yeast protein patterns analyzed by immobilized pH gradient two-dimensional gel electrophoresis.

An interlaboratory comparison was conducted on the positional and quantitative reproducibility of yeast proteins resolved by two-dimensional polyacrylamide gel electrophoresis (2-D PAGE) using isoelectric focusing with immobilized pH gradient (pH 4-7) in the first dimension. The basic experimental set-up was as follows: one laboratory prepared and distributed a [35S]methionine-labeled total yeast protein extract (Göteborg, Sweden), another laboratory prepared the IPG strips to be used by all labs in this study (Munich, Germany), the third laboratory (Aarhus, Denmark) circulated the protocols and coordinated the modest attempts to unify them. Samples were run horizontally in the first dimension and vertically in the second. The gels were sent to Göteborg for processing by phosphoimager technology and computerized image analysis (PDQuest), and the 2-D PAGE resolved proteins were located and quantified automatically. A subset of 470 spots was manually matched in all gels out of an average of 1328 resolved proteins. The positional interlaboratory comparison revealed great pattern reproducibility, the correlation coefficient in no case being less than 0.9994. In absolute terms an average deviation of 2.8 mm (x-position) and 1.8 mm (y-position) were obtained for all nine gels (three gels per lab). The interlaboratory comparison of protein quantitation displayed higher variability, and the best correlation coefficient generated was 0.975. An average standard deviation of 34.5% was calculated for protein quantitation including all three labs, a value slightly higher than the intralaboratory variation (range 20-28%). Thus, despite differences in protocols, chemicals and equipment, the immobilized pH gradient technology gave extremely high positional and quantitative reproducibility. This will greatly facilitate the exchange of data and the establishment of multi-user image-based 2-D gel databases.

Electrophoresis, Gel, Two-Dimensional↗

PubMed1995

Compression characteristics of CPR manikins.

We evaluated the force-depth compression characteristics of 8 different CPR manikins during mechanical cardiopulmonary resuscitation by a thumper. The force required to compress the manikin's thorax of 1, 2, 3, 4 and 5 cm was measured. It ranged between 6.3 and 14 kp at a depth of 1 cm, 11.6-30 kp at 2 cm, 17-38 kp at 3 cm, 22.5-54 kp at 4 cm and 28.5-69 kp at 5 cm. The manikins with a spring in the thorax (Ambu Man, Ambu MultiMan, Dräger CPR-Max, Laerdal Resusci Anne) as well as one without (Ambu CPR Pal) showed a rather linear relationship between depth and force required to compress the chest. Ambu Man, set at 'High', Laerdal Resusci Anne and Dräger CPR-Max revealed a slight increase in resistance, whereas 2 manikins without a spring (Laerdal Little Anne, Laerdal Family Trainer) and 1 manikin with a plastic spring-like construction (Actar 911) exhibited less resistance with increasing depth. According to our results, the manikins are not uniform in their compression characteristics; some become nonlinear when 3 cm of compression is exceeded. For correct CPR it is of utmost importance that the CPR trainee learns to compress in a sufficiently strong manner, but simultaneously to avoid an exceedingly high depth of compression irrespective of the thorax resistance. In order to prepare the CPR student for the varying chest resistances of the human body, we recommend to train CPR on manikins with different chest resistances.

Cardiopulmonary Resuscitation↗

PubMed1995

Pallister-Hall syndrome and McKusick-Kaufmann syndrome: one entity?

The Pallister-Hall syndrome is characterised by specific facial anomalies, postaxial polydactyly, imperforate anus, and brain anomalies including a diencephalic hamartoblastoma. The hallmarks of the McKusick-Kaufmann syndrome are hydrocolpos owing to vaginal atresia, postaxial polydactyly, imperforate anus, and congenital heart defects. We report a patient with the unique features of hydrocolpos, postaxial polydactyly, and hypothalamic hamartoblastoma and discuss the different aetiological considerations of both syndromes and implications for clinical management.

Abnormalities, Multiple↗

PubMed1994

Polymorphism of pepper (Capsicum annuum L.) seed proteins studied by two-dimensional electrophoresis with immobilized pH gradients: methodical and genetic aspects.

A population of ten morphologically similar inbred lines of pepper (Capsicum annuum L.) has been investigated for polymorphism of seed proteins by two-dimensional (2-D) electrophoresis with immobilized pH gradients. To reveal as much variation as possible, both the water- and the urea/detergent-soluble protein fraction were electrophoretically analyzed and subsequently visualized by silver staining. The 2-D patterns were subjected to computer analysis to be able to establish genetic variation. A high number of the seed proteins were found to be variable as to presence/absence: these were 68 out of 184 reproducible water-soluble proteins and 34 out of 419 reproducible urea/detergent-soluble proteins. Comparison of the 2-D data of the water-soluble and the urea/detergent-soluble proteins, which represent the biggest part of all extractable seed proteins, showed that both protein fractions have proteins in common, but the variable proteins found in both fractions were non-identical. The difference of variability scored in both solubility fractions was discussed. Genetic distances between all pairs of inbred pepper lines were calculated and a genetic tree was constructed. A correlation analysis was carried out to correct for genetic linkage and for secondary modifications, to have a more proper estimate of genetic distances. In both cases the dendrograms showed two distinct genetic groups of five inbred lines. This electrophoretic study was done in order to utilize the genetic distance data in breeding for heterosis. The genetic distance data presented will be used to validate the assumption that there is a higher chance to achieve better hybrid performance when the genetic distance between the parents is as great as possible.(ABSTRACT TRUNCATED AT 250 WORDS)

Breeding↗

PubMed1993

Spontaneous collapse of posttraumatic syringomyelia: serial magnetic resonance imaging.

The case of a 30-year-old man with posttraumatic syringomyelia involving the cervical and upper thoracic spine is reported. The patient was followed clinically and with magnetic resonance (MR) imaging over a 3-year period. Spontaneous complete remission of the syrinx-related symptoms correlated with a partial collapse of the syrinx, as proved by serial MR imaging.

Accidents, Traffic↗

PubMed1992

Elimination kinetics of maternally derived thyrotropin receptor-blocking antibodies in a newborn with significant thyrotropin elevation.

OBJECTIVE: To determine the course of maternally derived elevations in thyrotropin-binding inhibitory immunoglobulins in a neonate. DESIGN: Case report. SETTING: University pediatric endocrinology clinic and endocrine immunology laboratory in Ohio. PARTICIPANTS: An infant with elevated thyrotropin levels but near-normal total thyroxine levels, and her mother. INTERVENTIONS: None. MEASUREMENTS/MAIN RESULTS: Thyroid hormone, thyrotropin, and thyrotropin-blocking immunoglobulin concentrations were serially measured in a woman and her infant, who was found to have elevated thyrotropin levels (234 mU/L) and borderline low thyroxine levels (95 nmol/L). As infant thyroxine concentrations remained normal (125 to 145 nmol/L), no thyroxine supplementation was given. Thyrotropin levels decreased concomitantly with thyrotropin-blocking inhibitory immunoglobulin levels, and normalized by day 56 of life. The apparent elimination half-life of thyrotropin-blocking immunoglobulins was 7.5 days. CONCLUSIONS: The observed parallel elimination kinetics suggest that the thyrotropin receptor antibody acts as a thyrotropin antagonist, resulting in compensatory thyrotropin elevations. The duration of such elevations may be predicted on the basis of such elimination.

Autoantibodies↗

PubMedDate not supplied

Genetic variability of pepper (Capsicum annuum L.) seed proteins studied by 2-D electrophoresis with immobilized pH gradients.

Ten pepper (Capsicum annuum L.) inbred lines were successfully differentiated by two-dimensional electrophoresis with immobilized pH gradients. Qualitative polymorphism of water-soluble and urea/detergent-soluble seed proteins, respectively, was investigated by computer analysis and used for establishing a dendrogram derived from maximum-parsimony analysis. The dendrogram calculated from urea/detergent-soluble proteins shows four types of distance indices, whereas water-soluble proteins show two sets of inbred lines with similar intraset distance indices. The validity of the dendrograms with respect to quantitative inherited traits, such as cold tolerance and earliness, will be tested by field trials.

Capsicum↗

PubMedDate not supplied

Positional reproducibility of protein spots in two-dimensional polyacrylamide gel electrophoresis using immobilised pH gradient isoelectric focusing in the first dimension: an interlaboratory comparison.

An intra- and interlaboratory comparison of positional reproducibility of protein spots in two-dimensional electrophoresis using immobilised pH gradients (IPG) in the first dimension (IPG-DALT) was made. Aliquots of two different samples, human cardiac and barley leaf proteins, were separated in two different laboratories (London and Munich), using 180 mm long IPG gel strips, pH 4-8, for the first dimension and homogeneous SDS-PAGE gels (12% T) for the second dimension. Subsets of 340 (cardiac) and 200 (barley) well-resolved spots distributed across the 2-D gel patterns were selected for computer analysis (PDQUEST) of positional reproducibility. The IPG-dimension was highly reproducible in each laboratory, with a mean standard deviation of about 1 mm for both types of sample. Interlaboratory comparisons revealed identical results for barley with a mean standard deviation along the x-axis of about 1 mm, whereas the cardiac matchset showed slightly more variability (mean standard deviation approximately 1.5 mm). Nevertheless, IPG-DALT provides significantly improved reproducibility of spot positions compared to conventional isoelectric focusing with synthetic carrier ampholytes.

Electrophoresis, Gel, Two-Dimensional↗