Pediatric computed tomography doses in Germany from 2016 to 2018 based on large-scale data collection

PURPOSE

Accumulating evidence from epidemiological studies that pediatric computed tomography (CT) examinations can be associated with a small but non-zero excess risk for developing leukemia or brain tumor highlights the need to optimize doses of pediatric CT procedures. Mandatory dose reference levels (DRL) can support reduction of collective dose from CT imaging. Regular surveys of applied dose-related parameters are instrumental to decide when technological advances and optimized protocol design allow lower doses without sacrificing image quality. Our aim was to collect dosimetric data to support adapting current DRL to changing clinical practice.

METHOD

Dosimetric data and technical scan parameters from common pediatric CT examinations were retrospectively collected directly from Picture Archiving and Communication Systems (PACS), Dose Management Systems (DMS), and Radiological Information Systems (RIS).

RESULTS

We collected data from 17 institutions on 7746 CT series from the years 2016 to 2018 from examinations of the head, thorax, abdomen, cervical spine, temporal bone, paranasal sinuses and knee in patients below 18 years of age. Most of the age-stratified parameter distributions were lower than distributions from previously-analyzed data from before 2010. Most of the third quartiles were lower than German DRL at the time of the survey.

CONCLUSIONS

Directly interfacing PACS, DMS, and RIS installations allows large-scale data collection but relies on high data-quality at the documentation stage. Data should be validated by expert knowledge or guided questionnaires. Observed clinical practice in pediatric CT imaging suggests lowering some DRL in Germany is reasonable.

Determination of Semicarbazide in Baby Food by Liquid Chromatography/Tandem Mass Spectrometry: Interlaboratory Validation Study

An interlaboratory validation study funded by the European Commission, Directorate General for Health and Consumer Protection (DG SANCO), was conducted to evaluate the effectiveness of a liquid chromatography/tandem mass spectrometry (LC/MS/MS) method for the determination of semicarbazide (SEM) in different types of baby food at a possible future European regulatory limit (10 ng/g). The test portion of the sample was extracted with hydrochloric acid, and the analyte was derivatized with 2-nitrobenzaldehyde, with 1,2-[15N2, 13C] SEM as an internal standard. The extract was neutralized and then purified on a solid-phase extraction cartridge. The SEM was determined by reversed-phase LC with detection by MS/MS. Apple puree, rice pudding, and meat/vegetable meal baby food materials, spiked with SEM at levels of about 3, 10, and 30 ng/g, respectively, were sent to 20 laboratories in 12 different European countries, which submitted results from 17 participants. Recoveries ranged from 88.8 to 106.1%. Based on results for spiked samples (blind pairs at 3 levels), the relative standard deviations for repeatability (RSDr) ranged from 4.2 to 6.9% and the relative standard deviations for reproducibility (RSDR) ranged from 16.6 to 24.3%. The method showed acceptable within- and between-laboratory precision for all 3 matrixes, as evidenced by HorRat values, at the target levels for the determination of SEM.

[Development and validation of assessment instruments for shared decision making]

The German Ministry for Health and Social Security is funding ten projects to introduce shared decision making into clinical practice. The medical problems the projects are focussing on were chosen from among various diseases (e. g. depression, multiple sclerosis, cancer). The ten projects achieved consensus on a core set of instruments for the measurement of process and outcome of the shared decision making. Instruments developed in German-speaking countries are currently not available. Thus, linguistic and cultural validation had to be performed for the core set instruments. The results of the data analysis as well as patient interviews demonstrate the need for improving these instruments. Therefore, the members of the methodological working group concentrated on the integration of these results in a new instrument. In a first step the construct of "shared decision making" was defined, followed by a definition of the process elements characterising shared decision making. Thereafter, items were developed on the basis of the process elements. The new instrument will now be validated for different diseases.

Homeopathic remedies as metaphors in family therapy. A narrative-based approach to homeopathy

Objective: To examine a metaphorical, narrative model to explain the outcome of an homeopathic encounter involving the patient, practitioner and the homeopathic medicine.

Material and Methods: The transcript of a videotaped doctor–patient interaction from a European doctor–patient communication study (EUROCOM) was analysed using qualitative methods.

Results: Analysis demonstrates a narrative relationship between the protagonists in the therapeutic interaction, with the homeopathic medicine performing a metaphorical role.

Discussion: The results justify further investigation of the narrative and metaphorical properties of the therapeutic encounter in homeopathy.

Homeopathic remedies as metaphors in family therapy. A narrative-based approach to homeopathy

OBJECTIVE

To examine a metaphorical, narrative model to explain the outcome of an homeopathic, encounter involving the patient, practitioner and the homeopathic medicine.

MATERIAL AND METHODS

The transcript of a videotaped doctor-patient interaction from a European doctor-patient communication study (EUROCOM) was analysed using qualitative methods.

RESULTS

Analysis demonstrates a narrative relationship between the protagonists in the therapeutic interaction, with the homeopathic medicine performing a metaphorical role.

DISCUSSION

The results justify further investigation of the narrative and metaphorical properties of the therapeutic encounter in homeopathy.

[Metaphorical aspects of mistletoe therapy in patients' experiences--a qualitative study]

OBJECTIVE

Mistletoe therapy is an item of research because of its immunological features. Nevertheless, mistletoe should be also an item of research because of its semiotics. Long before R. Steiner proposed mistletoe as an anticancer drug, this plant seemed to have its meaning not by pharmacodynamics but by pharmacosemiotics and magic. Thus, metaphorical aspects of mistletoe therapy should be described by processing the transcript and paintings from a therapeutic group session of cancer patients. Especially the relation between individually and historically coded metaphors should be looked at.

MATERIAL AND METHODS

Sample of this qualitative study is the transcript of a therapeutic session of 12 female malignoma patients getting mistletoe infusions (Isorel(r)) since 1.5 years in a general practitioners' practice. Sequential coding of the transcript, inventory of themes, and structural hypothesis are the first steps. The structural hypothesis is triangulated by a textual corpus containing anthroposophic and ethnographic material; then a grounded theory is made.

RESULTS

The material is divided. On the one hand, there is a huge amount of historically coded, stereotypic metaphors (sun, cancer, ritual). On the other hand, 'ritual' seems not only a stereotypic metaphor but also a container of individually coded metaphors concerning body experiences (proprioceptive etc.). Metaphors from anthroposophy are rare - the metaphors seem to stem from a deeper level of ethnographic sources. The whole session has a polyphone narrative structure. Categories of semiotics such as icon, index and symbol are only by the context of interaction a suitable description for mistletoe's metaphoric function.

CONCLUSIONS

Problems of bias (denominator problem, valid but not reliable) are discussed, and a proposal is made for further forms of generalization of the results (semantic differentials). Moreover, it has to be asked if different preparations of mistletoe (e.g. lectine standard, draft from planta tota) make different halos of metaphors.

Normal ultrastructure, but altered stratum corneum lipid and protein composition in a mouse model for epidermolytic hyperkeratosis

Recently, we established keratin 10-deficient mice, serving as a model for the hyperkeratotic skin disorder epidermolytic hyperkeratosis. The considerable ichthyosis in these mice suggested alterations in terminal differentiation and in the formation of a functional epidermal barrier. Here, we report on the ultrastructural organization and composition of the stratum corneum lipids and on the expression of two major cornified envelope proteins. Electron microscopy of ruthenium tetroxide postfixed skin samples demonstrated a normal extrusion and morphology of lamellar bodies as well as the formation of bona fide lamellar layers in neonatal keratin 10-deficient mice. When we studied the composition of the major stratum corneum lipids, however, we found significant changes. Most importantly, the analysis of ceramide subpopulations revealed that the total amount of ceramide 2 was elevated in keratin 10-deficient mice, whereas ceramides 1, 3, 4, and 5 were decreased among total stratum corneum lipids. The amount of the ceramide precursors sphingomyelin and glucosylceramide was reduced in the stratum corneum without accompanying changes in the mRNA coding for acid sphingomyelinase. Notably, we found an increased mRNA and protein content for involucrin in neonatal keratin 10-deficient mice, whereas the expression of loricrin was not changed. Our data demonstrate that, although the formation of lipid layers in the stratum corneum appeared to be normal, its lipid composition is significantly altered in keratin 10-deficient mice.

The glycosphingolipidoses-from disease to basic principles of metabolism

The glycosphingolipidoses are a set of diseases that are caused by defects in the lysosomal degradation of glycolipids derived from the plasma membrane. By investigating the molecular bases of the diseases, basic principles of storage disease pathology and of membrane digestion were discovered. The generation of mouse models has facilitated the development of new and promising therapeutic strategies for these diseases, most of which are not treatable at present. Lately, the discovery of the importance of glycosphingolipid metabolism for skin development has opened a new and interesting field.

Sphingolipid activator proteins are required for epidermal permeability barrier formation

The epidermal permeability barrier is maintained by extracellular lipid membranes within the interstices of the stratum corneum. Ceramides, the major components of these multilayered membranes, derive in large part from hydrolysis of glucosylceramides mediated by stratum corneum beta-glucocerebrosidase (beta-GlcCerase). Prosaposin (pSAP) is a large precursor protein that is proteolytically cleaved to form four distinct sphingolipid activator proteins, which stimulate enzymatic hydrolysis of sphingolipids, including glucosylceramide. Recently, pSAP has been eliminated in a mouse model using targeted deletion and homologous recombination. In addition to the extracutaneous findings noted previously, our present data indicate that pSAP deficiency in the epidermis has significant consequences including: 1) an accumulation of epidermal glucosylceramides together with below normal levels of ceramides; 2) alterations in lipids that are bound by ester linkages to proteins of the cornified cell envelope; 3) a thickened stratum lucidum with evidence of scaling; and 4) a striking abnormality in lamellar membrane maturation within the interstices of the stratum corneum. Together, these results demonstrate that the production of pSAP, and presumably mature sphingolipid activator protein generation, is required for normal epidermal barrier formation and function. Moreover, detection of significant amounts of covalently bound omega-OH-GlcCer in pSAP-deficient epidermis suggests that deglucosylation to omega-OH-Cer is not a requisite step prior to covalent attachment of lipid to cornified envelope proteins.

Accumulation of protein-bound epidermal glucosylceramides in beta-glucocerebrosidase deficient type 2 Gaucher mice

The epidermal permeability barrier for water is essentially maintained by extracellular lipid membranes within the interstices of the stratum corneum. Ceramides, the main components of these membranes, derive in large part from hydrolysis of glucosylceramides mediated by the lysosomal enzyme beta-glucocerebrosidase. As analyzed in this work, the beta-glucocerebrosidase deficiency in type 2 Gaucher mice (RecNci I) resulted in an accumulation of all epidermal glucosylceramide species accompanied with a decrease of the related ceramides. However, the levels of one ceramide subtype, which possesses an alpha-hydroxypalmitic acid, was not altered in RecNci I mice suggesting that the beta-glucocerebrosidase pathway is not required for targeting of this lipid to interstices of the stratum corneum. Most importantly, omega-hydroxylated glucosylceramides which are protein-bound to the epidermal cornified cell envelope of the transgenic mice accumulated up to 35-fold whereas levels of related protein-bound ceramides and fatty acids were decreased to 10% of normal control. These data support the hypothesis that in wild-type epidermis omega-hydroxylated glucosylceramides are first transferred enzymatically from their linoleic esters to proteins of the epidermal cornified cell envelope and then catabolized to protein-bound ceramides and fatty acids, thus contributing at least in part to the formation of the lipid-bound envelope.

Type II collagen of lamprey

The major collagen in lamprey notochord is type II, as determined by its amino acid composition and solubility properties. This collagen has a distribution of charged residues indistinguishable from higher vertebrate Type II collagens as judged by its SLS banding pattern. Lamprey type II collagen has a higher thermal stability than lamprey skin collagen, in contrast to the identical melting temperatures for these types in mammals. A minor collagen in lamprey notochord has solubility properties, amino acid composition, and electrophoretic mobility similar to that of 1 alpha, 2 alpha, 3 alpha collagen in human cartilage.