[Metabolic monitoring: can monitoring of brain tissue oxygen partial pressure replace measurement of jugular venous oxymetry?].
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Blood Gas Monitoring, Transcutaneous↗
Biomedical subjects
A Jäger
Publications and source records attributed to A Jäger.
[3-D model analysis of the maxilla of infants with lip-jaw-palate clefts].
For the investigation of three-dimensional morphological changes in the maxilla of children with cleft lip and palate, the use of two-dimensional test analysis is inadequate. Since no standardised three-dimensional method has so far been available, a three-dimensional digital, computer-aided procedure was developed to visualize and metrically analyse the growth of the edentulous maxilla of infants with cleft lip and palate. Chronologically consecutive casts of the maxillas (obtained at the ages of one week, and three, six and twelve months) of five children with complete unilateral CLP were measured optically with the instrument Micromeasure 70. Following digitation, the casts were reconstructed in the computer, aligned and superimposed using the Orthosurf program. The distances between the surfaces were then measured; in addition, the surfaces were segmented perpendicular to the alveolar crest at reference points C1, C1', C2, C2' and I. The volumes of the resulting segments were determined and compare with one another. Specially designed software automated the following steps: 1. identification of reference points; 2. alignment of the cloud of points in a system of coordinates, and 3. identification of the alveolar crest. Our initial results show that (1) the new method enables visualization of the extent and direction of morphological changes of the mucosal surface, and (2) reproducible quantification of these changes via the determination of changes in the volume of defined alveolar segments. The three-dimensional analysis presented here permits a comprehensive three-dimensional measurement of the models of the edentulous maxilla of infants with cleft lip and palate.
Cephalometry↗
Multimodal hemodynamic neuromonitoring--quality and consequences for therapy of severely head injured patients.
Fifty-five head injured patients (GCS < 8) were studied at an average of 7.5 +/- 3.4 days on the ICU to check quality of hemodynamic monitoring and the consequences for therapy. Multimodal neuromonitoring included intracranial pressure (ICP), mean arterial pressure (MAP), cerebral perfusion pressure (CPP), endtidal CO2 (EtCO2) as well as brain tissue--pO2 (p(ti)O2), regional oxygen (rSO2) and jugular venous oxygen saturation (SjO2). Regional p(ti)O2 as well as global SjO2 were sensitive technologies to detect hemodynamic changes. However analyzing reliability and good data quality regional p(ti)O2 (up to 95%) was superior to jugular bulb oximetry (up to 50%). Longterm-measurements of rSO2 using near infrared spectroscopy reached, if possible, a restricted reliability (good data quality up to 70%) and sensitivity in comparison to p(ti)O2. Especially p(ti)O2 enabled detection of critical p(ti)O2 (< 15 mm Hg) in up to 50% frequency during the first days after trauma and a second peak after day 6 to 8 according to evidence of CPP insults. Knowledge of baseline p(ti)O2 and CO2-reactivity allowed minimizing risk of ischemia by induced hyperventilation and improvement on cerebral microcirculation after mannitol administration could be individually recognized.
Blood Pressure↗
[Acetabular reconstruction using acetabular reinforcement rings].
Reviewing the literature the revision arthroplasty of the hip joint with acetabular reinforcement rings shows good results concerning a follow-up period of six years in comparison with cemented or non-cemented primary implants. We use different acetabular reinforcement rings with differentiated indications. The primary assignment is the secure fixation of the ring to the vital bone. The acetabular bone defect is filled with autogenous or homogeneous bone grafts. The increasing number of massive acetabular defects made us develop a new acetabular reinforcement ring. It allows a better fixation than the Burch-Schneider Ring and is cheaper than the individual acetabular implant. Since 1988 we performed 262 revision arthroplasty with acetabular reinforcement rings. Until 1996 we evaluated 174 reinforcement rings (41 Müller rings, 72 Ganz rings, 41 Burch-Schneider rings, 6 RS or RSH ring, 5 individual acetabular implants). After an average follow-up period of 5.6 years a radiological or clinical loosening of the acetabular component occurred in only 6 patients (3.4%). To reach a better comparison of the surgical results we developed a score, which differentiate checks the operative goals. On plane pelvic radiographs we checked the reconstruction of the rotation center, the demarcation of the acetabular component and the outcome of the bone transplant.
Acetabulum↗
Integration host factor affects the oxygen-regulated expression of photosynthesis genes in Rhodobacter capsulatus.
The puf and puc operons of Rhodobacter capsulatus, which encode pigment binding proteins, are regulated by oxygen tension. Strain IR4 which carries a point mutation in the himA gene for integration host factor (IHF) shows a delayed increase in the amount of photosynthetic complexes after reduction of oxygen tension when compared to the isogenic wild-type strain. This delay in the formation of photosynthetic complexes correlates with a delay in increasing the level of transcription of the puf and puc operons, whereas the transcription of the bchD genes is not affected by IHF. Several IHF binding sites can be identified upstream of the puf and puc transcriptional starts by in vitro footprint analysis. Our results suggest that IHF facilitates the binding of other trans-acting factors, e.g. RegA, which in turn stimulate transcription of the puf and puc genes under low oxygen tension.
Bacterial Proteins↗
Clinical experience with 118 brain tissue oxygen partial pressure catheter probes.
OBJECTIVE: We assessed the technical and diagnostic reliability of partial pressure of oxygen (PO2) of brain tissue (P(ti)O2) monitoring. The monitoring system and the catheter probes were tested in vitro, and clinical experiences obtained with 118 brain P(ti)O2 catheter probes, used in 101 patients, are reported. METHODS: The polarographic (LICOX; Medical Systems Corp., Greenvale, NY) P(ti)O2 catheter probe lies 22 to 27 mm below the dura level; its PO2-sensitive surface is 7.1 mm2. For 10 patients, the adaptation time (with initially unreliable signals after insertion) was determined. For 27 patients, the probe was removed in a stepwise fashion (three increments of 5 mm) and the heterogeneity of brain P(ti)O2 levels was investigated. After removal of the catheter probes, their PO2 and zero display error values were determined and compared with probe performance data obtained in vitro with unused PO2 catheter probes. RESULTS: Small iatrogenic hematomas were observed for two patients (1.7%). No infection occurred after 6.7 +/- 3.9 days (mean +/- standard deviation) of monitoring. The technical complication (dislocation or defect) rate was 13.6%. The mean adaptation time was 79.0 +/- 51.7 min. A flow chart is presented, which helps to rule out artifacts. The mean P(ti)O2 measured at 22 to 27 mm below the dura was 23.8 +/- 8.1 mm Hg, at 17 to 22 mm was 25.7 +/- 8.3 mm Hg, at 12 to 17 mm was 33.0 +/- 13.3 mm Hg (P < 0.01, compared with the initial value), and at 7 to 12 mm was 33.3 +/- 13.3 mm Hg (P < 0.01). Recent catheter probe versions exhibited a PO2 display error of -1.2 +/- 5.1% (mean +/- standard deviation, n = 38) and a mean zero display error of 1.1 +/- 0.9 mm Hg (n = 34). The greatest PO2 display errors were measured during the first 4 days of continuous monitoring. In the in vitro test (of 12 unused catheter probes), the maximal probe display error was 1.07 +/- 2.14%, tested at temperatures between 22 degrees C and 37 degrees C and tested at oxygen pressures of 0, 44, and 150 mm Hg. In vitro, the zero display error was -0.21 +/- 0.25 mm Hg. CONCLUSION: Brain P(ti)O2 monitoring, reflecting an area 17 to 27 mm below the dura, is a safe and reliable technique for monitoring cerebral oxygenation. Excluding the first 1 hour after insertion, data are reliable, with almost 100% good data quality.
Artifacts↗
Dyskeratosis congenita: multisystemic disorder with special consideration of immunologic aspects. A review of the literature.
Dyskeratosis congenita (DC) is a rare, predominantly X-linked multisystemic disorder. It demonstrates a wide spectrum of clinical manifestations and typically presents with dermatologic symptoms during the first decade of life. This review of the literature points out the importance of hematologic and immunologic alterations in defining the course and prognosis of the disease process. Pancytopenia as well as the humoral and cellular disturbances in immunologic functions associated with this disease complex may lead to severe infections that represent the main cause of death. The pathogenesis of DC is still unclear and a curative therapy is presently lacking. Recent reports suggest that a beneficial effect may be observed in the administration of hematopoietic growth factors (G-CSF, GM-CSF) for patients with DC and neutropenia.
Adolescent↗
Brain tissue pO2 and outcome after severe head injury.
Although the use of on-line monitoring of brain ti-pO2 is increasing, so far the critical level of 10 mmHg is derived from animal experiments and clinical analyses: no hard proof on outcome basis has been given until now. The authors present an outcome analysis of 35 patients with severe head injury. Inclusion criteria were: start of ti-pO2 monitoring < or = 40 h post-injury, the probe lying in CT scan normal tissue and the GOS at 6 months being available. The good outcome group (GOS 4 + 5, n = 17) showed a 17.7+/-9.1 h delay from the injury to the monitoring compared to the bad outcome group (GOS 1-3, n = 18) with (14.2+/-9.1 h) (p < 0.05). Age and initial Glasgow Coma Score were not different. In the bad outcome group there were more patients with a diffuse injury type 3 and 4. The distribution of the ti-pO2 values show in all the examined time intervals (day 0-6, 0-72 h, 0-48 h and 0-24 h) a left shift in the bad outcome group with most pronounced difference for ti-pO2 < or = 10 mmHg. For the period from 0-48 h and even more from 0-24 h post-injury, the difference between both groups was significant (p = 0.036 and p = 0.013). In the bad outcome group 35.5% of the values from 0-24 h were < 10mmHg (compared to 10.6% in the good outcome group. ti-pO2 values > or = 50 mmHg were seen more often in the bad outcome group; this occurred mainly after 48-72 h post-injury. The authors concluded that brain ti-pO2 monitoring is able to detect the occurrence of early hypoxic insults. Brain ti-pO2 monitoring is an important parameter in the multimodality monitoring system.
Adult↗
Identification, sequence analysis, and expression of the lepB gene for a leader peptidase in Rhodobacter capsulatus.
The leader peptidase (signal peptidase I) gene, lepB, of Rhodobacter capsulatus has been cloned and sequenced. The amino acid sequence of the predicted protein exhibits similarity to other known bacterial leader peptidases. R. capsulatus belongs to the alpha-subdivision of purple bacteria and thus is a relative of mitochondria in eukaryotes. Like the yeast mitochondrial inner membrane proteases IMP1 and IMP2, the leader peptidase from Rhodobacter has only one membrane-spanning segment. Sequence comparison of the Rhodobacter Lep protein with IMP1 and IMP2 did not reveal a higher overall similarity than between other prokaryotic signal peptidases and the mitochondrial enzymes. Expression studies using lacZ fusions in combination with primer extension analysis provide evidence for a weak promoter located a short distance from the transcription start of the lepB gene. Failure to establish a Rhodobacter strain with a disrupted lepB gene indicates that this gene is essential.
Amino Acid Sequence↗
Evaluation of orthodontic treatment with early extraction of four second molars.
The outcome of orthodontic treatment involving early extraction of 4 second molars was evaluated in 52 patients (29 girls, 23 boys). Computer-assisted analysis of cephalograms, casts and panoramic X-rays was performed at the start (T1, mean age 11.5 years) and at the end (T2, mean age 14.4 years) of treatment. Following treatment, mesial migration of upper and lower first molars was counteracted; however, treatment only moderately influenced normal development of the position of the incisors and the profile. At the end of treatment, the third molars had erupted in only 3 patients. Nevertheless, on average a significant mesial movement of these teeth was observed. In addition, there was a significant improvement in the axial inclination of the third molars, especially in the upper arch. This improvement was correlated with the original position of the teeth. All patients needed a longer follow-up period and it seems reasonable that some of them might require a second treatment phase to adjust the position of the third molars.
Adolescent↗
Identification and analysis of the rnc gene for RNase III in Rhodobacter capsulatus.
The large subunit ribosomal RNA of the purple bacterium Rhodobacter capsulatus shows fragmentation into pieces of 14 and 16S, both fragments forming the functional equivalent of intact 23S rRNA. An RNA-processing step removes an extra stem-loop structure from the 23S rRNA [Kordes, E., Jock, S., Fritsch, J., Bosch, F. and Klug, G. (1994) J. Bacteriol., 176, 1121-1127]. Taking advantage of the fragmentation deficient mutant strain Fm65, we used genetic complementation to find the mutated gene responsible for this aberration. It was identified as the Rhodobacter homologue to mc from Escherichia coli encoding endoribonuclease III (RNase III). The predicted protein has 226 amino acids with a molecular weight of 25.5 kDa. It shares high homology with other known RNase III enzymes over the full length. In particular it shows the double-stranded RNA-binding domain (dsRBD) motif essential for binding of dsRNA substrates. The Fm65 mutant has a frame shift mutation resulting in complete loss of the dsRBD rendering the enzyme inactive. The cloned Rhodobacter enzyme can substitute RNase III activity in an RNase III deficient E. coli strain. Contrary to E. coli, the Rhodobacter mc is in one operon together with the lep gene encoding the leader peptidase.
Amino Acid Sequence↗
Effect of the pufQ-pufB intercistronic region on puf mRNA stability in Rhodobacter capsulatus.
Differential expression of genes localized within the polycistronic puf operon of Rhodobacter capsulatus is partly due to altered stabilities of individual mRNA segments. We show that the 5' untranslated region (UTR) of pufB contributes to the unusual longevity of the 0.5 kb light-harvesting (LH) I specific pufBA mRNA and of the 2.7 kb pufBALMX mRNA. Three stem-loop structures have been identified within the pufQ-pufB intercistronic region by means of RNA secondary-structure analysis in vitro and in vivo. Deletion analysis of the pufB 5' UTR indicates that the complete set of secondary structures is required to maintain wild-type levels of pufBA mRNA stability. A phylogenetic comparison of pufB 5' UTRs of other photosynthetic bacteria reveals an evolutionary conservation of the base-pairing potential despite sequence divergence. Comparison of puf mRNA decay in Escherichia coli strains with or without endoribonuclease E (RNase E) activity suggests that the pufB 5' secondary structures protect the downstream mRNA segment against degradation by RNase E. Removal of the 117-nucleotide pufQ-pufB intercistronic region results in loss of stability for the pufBA and pufBALMX mRNAs with concomitant stabilization of the full-length puf primary transcript (QBALMX). We therefore conclude that the deleted sequence functions both as a stabilizing element for pufBALMX and pufBA segments and as a target site for initial rate-limiting decay of the unstable pufQBALMX mRNA.
Bacterial Proteins↗
Histomorphometric study of age-related changes in remodelling activity of human desmodontal bone.
To study age-related changes in human desmodontal bone remodelling, histological specimens were prepared from 42 human mandibles from individuals aged between 16 and 71 years which were obtained from autopsies. Microradiographs of horizontal ground sections and the corresponding undecalcified histological sections stained with Goldner trichrome were used for analysis. Histomorphometric measurements of static bone remodelling were performed along the desmodontal bone surface using a computer assisted semiautomatic measurement system. External influences from the individual dental occlusion and periodontal conditions were superimposed on age changes. A modest but significant age-dependent decrease in the surface extent of osteoid seams covered by 'active' osteoblasts was found. In addition, the number of osteoclasts per unit of resorptive bone surface diminished, leading to an increase in Howship's lacunae, devoid of osteoclasts. Both phenomena were interpreted as being due to a decrease in active bone forming capacity with age.
Adolescent↗
[Genioplasty. The long-term results after chin osteotomies with stable osteosynthesis].
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Adolescent↗
[The motivation and experiences of patients in connection with orthodontic-oral surgery combined therapy. A patient survey with consideration of the clinical and psychosocial factors].
In a retrospective study 140 patients, 97 females and 43 males who had undergone combined orthodontic surgical therapy between 1984 and 1992, were interviewed using a questionnaire. The "closed form" questions were designed to provide insight into the patients' motivations for seeking treatment and into their perceptions of its course and outcome. Nine working hypotheses taken from the literature served as the study's starting point. The evaluation of the data gathered revealed that, contrary to other studies, the motivation for patients to seek treatment was not directly related to sex, i.e., was not sex specific, although this must be qualified. The unequal distribution of the sex of the patients who had sought treatment, and who were covered in the survey, points to differences between them in their decision making processes. When the results were evaluated, the data showed 92.2% patient satisfaction and even high satisfaction with treatment outcome. 86.4% of the patients stated that they would recommend the operation to others and 82.9% said that they would undergo the operation again. This high level of patient satisfaction was to a great degree directly attributable to, above all, the positive aesthetic result, the quality of the consultation and care, and to the absence of persisting postoperative complications. When the patients were divided into subgroups by means of using single criteria, significant varying degrees of satisfaction could be distinguished among segments of the subgroups. It was not possible, however, through the use of cluster analysis to separate out with precision the small group of patients who were not satisfied with the overall results of their treatment.
Adolescent↗
[Indications, technique and results of bimaxillary surgery].
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Dental Occlusion, Balanced↗
[The differential diagnostic value of skeletal, dental and soft-tissue analyses in the planning of orthodontic-oral surgical therapy. A retrospective study of treated patients with skeletal Angle class III].
The study evaluated the orthodontic documentation gathered in the course of conducting combined surgical-orthodontic therapy on 45 skeletal angle class III patients. In 15 of the patients Le Fort I osteotomy of the maxilla was performed, in 15 sagittal split osteotomy of the mandible, and in the last 15 patients bimaxillary surgery. The purpose of the study was to evaluate by means of a retrospective analysis of cephalograms taken prior to surgery the role hard tissue, soft tissue, and dental cephalometric variables play in the choice of the type of surgery to be performed. Discriminate analysis was used to determine the ability of the individual parameters to predicate accurately the type of the surgery that had been carried out. The study revealed that the skeletal relationship diagnosed in the x-rays was suitable primarily in the differentiation of the monomaxillary and bimaxillary patients who had undergone surgery. Using discriminate analysis the accuracy to predict group membership was 75.6% for the skeletal parameters of the McNamara analysis and 67.5% for those of the Bergen analysis. Differentiation between the cases where surgery had been performed solely in the maxilla and those where surgery had been performed only in the mandible was most successful using the soft tissue parameters describing the position of the subnasale and the position of the lower lip in relation to the aesthetic line according to Ricketts. In addition, the arrangement of the lower incisors was more retrusive in the cases with isolated surgery in the maxilla. Discriminate analysis applying a combination of skeletal, dental, and soft tissue parameters had a capability to predict accurately in 93.3% of the patients the form of the chosen surgical procedure.
Adult↗
Investigation of the imaging properties of an x-ray film scanner.
In this note, the imaging properties of a CCD x-ray film scanner were investigated. The relationship between optical density and the logarithm of output pixel value provides information on the linearity of the system. The resolution properties of the scanner can be characterized by the presampling modulation transfer function which was calculated from a set of line spread functions with various alignments relative to the sampling grid. Our results show that the scanner is linear up to 2.0 optical density units, which leads to restrictions in digitizing x-ray films with higher optical density. The measured MTF shows the good spatial resolution of the CCD scanner which is demonstrated on an example.
Equipment Failure Analysis↗