The principle of regulation in biology--from bone to eating behavior.

Cell physiology and molecular biology typically follow a reductionistic approach in science. In the last decade, molecular principles and pathogenetic factors involved in the development of many diseases have been successfully discovered. Therefore, early biological concepts based on systemic and cybernetic thoughts have been largely overshadowed by these more recent molecular and pathogenetic factors. This review highlights discoveries on bone development and hypothalamic controlled feeding and eating behavior with a cybernetic and systemic perspective. Interestingly, ancient ideas on bone development and hypothalamic function are still reasonable considerations to embed new molecular discoveries into a systemic concept of principles organizing nature.     

Long-term course of epilepsy in a large cohort of intellectually disabled patients.

This study was designed to describe the course of epilepsy (in terms of seizure frequency) and to assess the variables (antiepileptic therapy regimens and others) correlated to improvement. Seizure frequency (categories: seizure free, more than one seizure/year, monthly seizures, weekly seizures and daily seizures) and antiepileptic medication were retrospectively compared between 1992 and 2002 in a large cohort of 550 inpatients with chronic epilepsy and different degrees of intellectual disability or multiple handicaps. RESULTS: Seizure frequency decreased significantly (p<0.001). 218 of the 394 patients (55.3%) not seizure free in 1992 improved (changed into a better frequency category). The improvement rate was marginally higher in patients who had undergone a medication change (p=0.08). A high seizure frequency in 1992 (p=0.016) and older age (p=0.006), but not epilepsy syndrome or degree of intellectual disability, were predictors for improvement (stepwise logistic regression analysis). 56.4% of the improved patients were on combinations of two AEDs (17.4%, monotherapy; 20.2%, triple therapy). The most frequent therapy regimens in the improved patients were lamotrigine/valproate (48 patients), carbamazepine/phenobarbital (21) and carbamazepine only (19). Lamotrigine/valproate was effective in all kinds of epileptic syndromes. Most patients on lamotrigine had serum concentrations above 10microg/ml, approximately one half had dosages above 200mg/day. The rate of seizure freedom increased from 28.4 to 37.6%. The 84% of the patients seizure free in 1992 remained seizure free. Predictors for seizure freedom in 2002 were higher age (stepwise logistic regression, p<0.0005) and seizure freedom in 1992 (p<0.0005). CONCLUSIONS: Substantial improvement can be achieved even in intellectually disabled patients with chronic epilepsy. Although the rate of seizure freedom is reduced in comparison with a non-ID population, once seizure freedom has been achieved it is most likely to continue. For a majority of this patient population, monotherapy may not be sufficient. Lamotrigine/valproate appears to be a major therapeutic innovation.     

Bacterial ghosts (BGs)—Advanced antigen and drug delivery system

Bacterial ghosts (BGs) are empty bacterial envelopes of Gram-negative bacteria produced by controlled expression of cloned gene E, forming a lysis tunnel structure within the envelope of the living bacteria. BGs are devoid of cytoplasmic content and possess all bacterial bio-adhesive surface properties in their original state while not posing any infectious threat. BGs are ideally suited as an advanced drug delivery system (ADDS) for toxic substances in tumor therapy. The inner space of BGs can be loaded with either single components or combinations of peptides, drugs or DNA which provides an opportunity to design new types of (polyvalent) drug delivery vehicles. Uptake of BGs loaded with Doxorubicin (Dox) by CaCo2 cells led to effective Dox release from endo-lysosomal compartments and accumulation in the nucleus. Viability and proliferative capacity of the cells were significantly decreased (2–3 orders of magnitude) after internalization of Dox loaded BGs as compared to cells incubated with free Dox. The same effect was observed with leukemia cells. Melanoma cells also revealed a high capability to internalize BGs. These results indicate that BGs are able to target a range of types of cancer. BGs have also been investigated as DNA delivery vectors. Studies show DNA loaded BGs are efficiently phagocytosed and internalized by both professional APCs and tumor cells with up to 82% of cells expressing the plasmid-encoded reporter gene. Our studies with BGs as an ADDS system contribute (i) to optimize drug delivery for the treatment of cancer; (ii) define specific conditions for selection and preparation of BG formulations; (iii) and provide a background for the clinical application of BGs in cancer therapy.     

Anaphylaxis to isosulfan blue and cross-reactivity to patent blue V: case report and review of the nomenclature of vital blue dyes.

BACKGROUND: Blue dyes used for lymphatic mapping in sentinel lymph node biopsy cause intraoperative anaphylactic reactions in up to 2.7% of patients. With increasing implementation of this technique, the incidence of anaphylaxis to these dyes can be expected to increase. In the literature, the chemically often unrelated and inconsistently designated dyes have been confused, adding to other inconsistencies in the nomenclature. OBJECTIVE: To demonstrate the nomenclature, chemical and physiologic differences, and allergenicity of the various blue dyes used in a medical context. METHODS: We describe a patient with an intraoperative grade IV anaphylactic reaction to isosulfan blue. Immediate-type hypersensitivity was proved by positive skin test reactions and CD63 expression to isosulfan blue and cross-reactivity to patent blue V. RESULTS: A review of the literature clarified the exact nomenclature of the blue dyes and the possible pitfalls of confusing nomenclature in the context of structurally closely related dyes with different allergenic properties. For the detection of type I hypersensitivity, intracutaneous tests are valuable tools. An IgE-mediated mechanism has been shown recently. In most cases, sensitization exists without known previous exposure in a medical context. This may be due to the widespread use of such dyes in objects of everyday life. Preoperative antiallergic medication use does not prevent anaphylactic reactions but apparently reduces their severity. CONCLUSION: For better comparison and precision, the Chemical Abstracts Service number of the respective dye should always be given.     

The 'Functional Muscle-Bone Unit': probing the relevance of mechanical signals for bone development in children and adolescents.

The present text deals with the relationship of muscle force and mass to bone mass and geometry in the developing skeleton of children and adolescents. Recent results of the last ten years are discussed with reflection on Harold Frost's 'mechanostat hypothesis'. Bone mass and geometry follow the development of body size and muscle force in children and adolescents. Thereby, bone is adapted to the tissue strain due to biomechanical forces. This process is modified by hormonal signals (i.e., estrogens and androgens). Therefore, the quantified relationship of muscle force to bone stability is a reasonable approach to distinguish between primary and secondary bone diseases. Primary bone diseases are characterized by a disturbed adaptation of bone to biomechanical forces. In contrast, secondary bone diseases show a correct adaptation of bone to loaded forces in combination with a decline of muscle force. Therefore, the 'Functional Muscle-Bone Unit' was introduced into the diagnostics of pediatric bone diseases. The ratio of two parameters--referred to bone strength on the one and to biomechanical forces on the other side--is a reasonable diagnostic approach to distinguish between primary and secondary bone diseases.     

Propagation of hepatitis A virus in human embryo fibroblasts

human diploid fibroblasts and human primary liver cell carcinoma cells (PLC/PRF/5) were infected with hepatitis A virus (HAV) adapted to growth in cell culture or derived directly from human stool. Viral antigen was expressed in PLC/PRF/5 cells 28 days after infection with cell culture-adapted HAV, and 50 days after infection with virus from human stool. In human fibroblasts the periods until first expression of viral antigen were 90 and 210 days, respectively. During further passages of HAV in fibroblasts the time of first appearance of antigen decreased to about 28 days. Biophysical properties of HAV extracted from infected fibroblasts were comparable to those of HAV derived directly from human stool. Immunofluorescence studies showed that the antigen was located exclusively within the cytoplasm of the infected fibroblasts. Kinetics of antigen production indicated that an equilibrium between virus multiplication and cell metabolism was reached in persistently infected fibroblasts.     

IFN-gamma-enhanced allergen penetration across respiratory epithelium augments allergic inflammation

BACKGROUND: Respiratory allergen contact is the critical event in the elicitation and boosting of allergen-specific immune responses, as well as in the induction of immediate and late inflammatory reactions. OBJECTIVE: We sought to investigate the influence of various factors of allergic inflammation on the integrity and barrier function of respiratory epithelium for allergens. METHODS: We cultured the human bronchial epithelial cell line 16HBE14o- in a transwell culture system as a surrogate of intact respiratory epithelium and used purified iodine 125-labeled recombinant major birch pollen allergen (rBet v 1) to study the extent, kinetics, and factors influencing transepithelial allergen penetration. RESULTS: Culture supernatants from activated allergen-specific T H 1 clones decreased transepithelial resistance. A screening of various factors (histamine, IFN-gamma, IL-1beta, IL-2, IL-3, IL-4, IL-5, IL-8, IL-12, and TNF-alpha) identified IFN-gamma as a potent factor capable of reducing epithelial barrier properties and enhancing transepithelial allergen penetration. Increased submucosal allergen concentrations caused by IFN-gamma-mediated reduction of epithelial barrier function provoked a more than 7-fold augmentation of histamine release from sensitized basophils. CONCLUSION: These results demonstrate that the T H 1 cell-derived cytokine IFN-gamma facilitates allergen penetration through the respiratory epithelium and thereby can aggravate allergic inflammation.