[Therapy of inherited diseases of platelet function. Interdisciplinary S2K guideline of the Permanent Paediatric Committee of the Society of Thrombosis and Haemostasis Research (GTH e. V.)]

Inherited disorders of platelet function are a heterogeneous group. For optimal prevention and management of bleeding, classification and diagnosis of the underlying defect are highly recommended. An interdisciplinary guideline for a diagnostic approach has been published (AWMF # 086-003 S2K; Hämostaseologie 2014; 34: 201-212). Underlying platelet disorder, platelet count, age and clinical situation modify treatment. Exclusive transfusion of platelet concentrates may be inappropriate as potentially adverse effects can outweigh its benefit. A stepwise and individually adjusted approach for restitution and maintenance of haemostasis is recommended. Administration of antifibrinolytics is generally endorsed, but is of particular use in Quebec disease. Restricted to older children, desmopressin is favourable in storage pool disease and unclassified platelet disorders. Although licensed only for patients with Glanzmann thrombasthenia and alloantibodies, in clinical practice rFVIIa is widely used in inherited platelet disorders with severe bleeding tendency. This guideline aims at presenting the best available advice for the management of patients with inherited platelet function disorders.

Mechanistic modelling of toxicokinetic processes within Myriophyllum spicatum

Effects of chemicals are, in most cases, caused by internal concentrations within organisms which rely on uptake and elimination kinetics. These processes might be key components for assessing the effects of time-variable exposure of chemicals which regularly occur in aquatic systems. However, the knowledge of toxicokinetic patterns caused by time-variable exposure is limited, and gaining such information is complex. In this work, a previously developed mechanistic growth model of Myriophyllum spicatum is coupled with a newly developed toxicokinetic part, providing a model that is able to predict uptake and elimination of chemicals, as well as distribution processes between plant compartments (leaves, stems, roots) of M. spicatum. It is shown, that toxicokinetic patterns, at least for most of the investigated chemicals, can be calculated in agreement with experimental observations, by only calibrating two chemical- specific parameters, the cuticular permeability and a plant/water partition coefficient. Through the model-based determination of the cuticular permeabilities of Isoproturon, Iofensulfuron, Fluridone, Imazamox and Penoxsulam, their toxicokinetic pattern can be described with the model approach. For the use of the model for predicting toxicokinetics of other chemicals, where experimental data is not available, equations are presented that are based on the log (P oct/wat) of a chemical and estimate parameters that are necessary to run the model. In general, a method is presented to analyze time-variable exposure of chemicals more in detail without conducting time and labour intensive experiments.

Effects of light and temperature fluctuations on the growth of Myriophyllum spicatum in toxicity tests--a model-based analysis

Laboratory toxicity tests are a key component of the aquatic risk assessments of chemicals. Toxicity tests with Myriophyllum spicatum are conducted based on working procedures that provide detailed instructions on how to set up the experiment, e.g., which experimental design is necessary to get reproducible and thus comparable results. Approved working procedures are established by analyzing numerous toxicity tests to find a compromise between practical reasons (e.g., acceptable ranges of ambient conditions as they cannot be kept completely constant) and the ability for detecting growth alterations. However, the benefit of each step of a working procedure, e.g., the random repositioning of test beakers, cannot be exactly quantified, although this information might be useful to evaluate working procedures. In this paper, a growth model of M. spicatum was developed and used to assess the impact of temperature and light fluctuations within the standardized setup. It was analyzed how important it is to randomly reassign the location of each plant during laboratory tests to keep differences between the relative growth rates of individual plants low. Moreover, two examples are presented on how modeling can give insight into toxicity testing. Results showed that randomly repositioning of individual plants during an experiment can compensate for fluctuations of light and temperature. A method is presented on how models can be used to improve experimental designs and to quantify their benefits by predicting growth responses.

[Monosystemic, oligolesional Langerhans cell histiocytosis. A rare congenital dermatosis]

A five-day-old female infant presented with congenital red-livid papules and nodules on the head, chest, back and left arm. The nodule on the chest was ulcerated at birth. The pregnancy and delivery were uneventful. There was no history of birth trauma to account for the ulcerated lesion. The parents and the three older siblings were healthy without similar skin lesions. The skin biopsy showed in the deep layer of the dermis a multinodular, granulomatous histiocytic infiltrate. The histiocytic cells expressed S-100 and CD1a. There were additionally many eosinophils. The suspected diagnosis Langerhans cell histiocytosis was confirmed by the histologic results. The patient was referred to pediatric hematology-oncology where evaluation showed no evidence of systemic involvement. The clinical, radiological, sonographic and histological results led to the diagnosis of a congenital, monosystemic, oligolesional Langerhans cell histiocytosis of the skin. In addition to the case presentation, we review the current stand of knowledge of the pathogenesis, the clinical classification and the therapy of the Langerhans cell histiocytosis.

Sequential myelin protein expression during remyelination reveals fast and efficient repair after central nervous system demyelination

To understand the mechanisms of remyelination and the reasons for regeneration failure is one of the major challenges in multiple sclerosis research. This requires a good knowledge and reliable analysis of experimental models. This work was undertaken to characterize the pattern of myelin protein expression during experimental remyelination. Acute demyelination of the corpus callosum was induced by feeding of 0.3% cuprizone for 6 weeks, followed by a 10-week remyelination period. We used a combination of Luxol fast blue (LFB) myelin staining, electron microscopy (EM) and immunohistochemistry for the myelin proteins 2',3'-cyclic nucleotide 3' phosphodiesterase (CNPase), myelin basic protein (MBP), proteolipid protein (PLP) and myelin oligodendrocyte glycoprotein (MOG). Early remyelination was detected by the re-expression of CNPase, MBP and PLP as early as 4 days. MOG, as a marker for late differentiation of oligodendrocytes, was not detectable until 2 weeks of remyelination. EM data correlated well with the LFB myelin staining and myelin protein expression, with 50% of the axons being rapidly remyelinated within 2 weeks. While particularly MBP but also PLP and CNPase are re-expressed very early before significant remyelination is observed by EM, the late marker MOG shows a lag behind the remyelination detected by EM. The presented data indicate that immunohistochemistry for various myelin proteins expressed early and late during myelin formation is a suitable and reliable method to follow remyelination in the cuprizone model. Furthermore, investigation of early remyelination confirms that the intrinsic repair programme is very fast and switched on within days.

Relation between perceived driving disability and scores of vision screening tests

AIM

To determine the relation between perceived driving disability and vision screening tests.

METHODS

93 subjects, aged 50 years and over, with binocular visual acuity of at least 20/80. Perceived driving disability (PDD) was assessed by a questionnaire. Subtracting daytime from night-time driving question scores revealed PDD at night (PDDN), subtracting scores of questions for driving in familiar places from those in unfamiliar places revealed PDD at unfamiliar places (PDDU).

RESULTS

PDD was strongly related to visual acuity, contrast sensitivity and useful field of view (UFOV). Specific relations existed between PDDN and Nyktotests and Mesotests and between PDDU and UFOV. These associations were enhanced in a subset of subjects with better visual acuities.

CONCLUSIONS

Vision screening tests correlate well with perceived driving disabilities, especially when a subtraction method is used in the questionnaire to reveal condition dependent disabilities. Additional tests for visual acuity are useful, especially in subjects with better visual acuity.

[Clinical significance of objective vision assessment using visually evoked cortical potentials induced by rapid pattern sequences of different spatial frequency]

BACKGROUND

In patients where reliable subjective assessment of visual acuity is impossible, further diagnostics should be enhanced by an objective method.

PATIENTS AND METHODS

A group of 34 patients was examined by objective assessment of visual acuity using visual evoked potentials (VEP) as described by Hajek and Zrenner in 1988. The presentation of five checkerboards with different spatial frequency in repetitive sequences on a TV-monitor elicits a series of transient visual evoked potentials. Shape and amplitude of each wavelet depends on check size and directly reflect a spatial tuning function with a low- and high-frequency cut-off. This amplitude is described by a polynomial fit (2nd order). The function's intersection with the x-axis at higher spatial frequencies leads to an estimation of the visual acuity.

RESULT

This result is compared to the subjectively determined visual acuity. In the majority of the presented cases the suspected malingering was confirmed.

CONCLUSION

Patients with suspected malingering represent the primary indication of the described method.

[Intrapalpebral migration of a form stable contact lens: a rare complication in contact lens practice]

PURPOSE

To demonstrate a rare complication in contactology.

CASE REPORT

A 26-year-old female had "lost" her hard contact lens in the right eye 2 years previously. Afterwards, new contact lenses were not tolerated. The patient had a slight intermittent epiphora but no further complaints. She consulted her ophthalmologist for new spectacles. At presentation, there was a firm tumour without signs of inflammation in the right upper lid area. When the lid was everted a hard contact lens was found within the tarsal plate which could be easily removed in the operating room. Microbiologic investigation disclosed no bacteria. Histology showed a circumscribed papillary reaction and a chronic non-specific inflammation with few eosinophils and no giant cells. Two weeks later the lens-related cavity was only slightly filled up by granulation tissue.

CONCLUSIONS

After "loss" of a contact lens superior dislocation and finally tarsal implantation should be kept in mind. The process of contact lens migration reveals some interesting features: 1. Generally, it causes only minor symptoms though it may last for years. 2. Bacterial contamination rarely occurs. 3. Histologically, the inflammation is often mild or even absent. Eosinophils and giant cells are of minor or no importance indicating that allergy and giant-cell reaction play no significant role. 4. The lens related cavity probably heals slowly, possibly because of a (partial) epithelialization.

Substitution of anti-human globulin by protein A-bearing staphylococci in the detection of Brucella antibodies

A coagglutination test using protein A-bearing staphylococci has been developed for the detection of Brucella antibodies. Comparing the results of a random sample of 57 sera collected from Malta fever patients, suggestive titers of 1: greater than or equal to 160 were found in 8 sera (14%) with the standard agglutination test, in 22 sera (39%) with the Coombs test, and in 23 sera (40%) with the coagglutination test. The titers in the Coombs test and the coagglutination test coincided in 54 (95%) of the 57 sera, in 3 sera (5%) the difference was no more than one dilution step. Sera from healthy subjects and patients with infections other than brucellosis showed titers up to 1:40 in all three tests. Because of its sensitivity and specificity in detecting non-agglutinating antibodies, the Brucella-antibody coagglutination test may replace the Coombs test as a complementary assay to the standard agglutination. Native sera from Malta fever patients frequently show a prozone phenomenon in the standard agglutination test and a reduced agglutinate formation in both the Coombs test and the coagglutination test. The inhibitors of agglutination lattice formation are apparently serum beta-lipoproteins which become attached to the Brucella antigen and can be removed from the serum by treatment with MnCl2-heparin.