Serotoninbestimmungen an Thrombocyten und an Fraktionen von Thrombocyten

Zusammenfassung Aus Suspensionen zerstörter Thrombocyten des Menschen wurden reine Fraktionen von Hyalomer und Granulomer hergestellt. Von den Fraktionen wurde jeweils ein Teil für die elektronenmikroskopische Untersuchung, ein anderer Teil für die Bestimmung des Serotonins verwandt. Durch die elektronenmikroskopische Untersuchung jeder einzelnen Fraktion wurde die Reinheit der Fraktionen überprüft. Die Bestimmung des Serotoningehaltes erfolgte am isolierten Rattenmagen. In Kontrollversuchen wurde ferner der Serotoningehalt intakter Thrombocyten bestimmt.Intakte Thrombocyten besitzen im Mittel einen Serotonin-Gehalt von 52 ng/10⁸ Thrombocyten. In den Fraktionierungsversuchen fanden wir 95% des Serotonins in den Hyalomer-Fraktionen und nur 5% des Serotonins in den Granulomer-Fraktionen. In vivo findet sich also der hohe Serotoningehalt fast ausschließlich im Hyalomer der Thrombocyten.

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Summary Pure fractions of hyalomer and granulomer were prepared from suspensions of destroyed human thrombocytes. One portion of the fractions was used for the electron microscopic studies, and the other part for the determination of serotonin (5-hydroxytryptamine). The electron microscopic investigation allowed to check the purity of each single fraction. On the isolated rat stomach the determination of the concentration of serotonin was performed. In control preparations we studied the serotonin concentration of intact thrombocytes. These thrombocytes have a mean serotonin concentration of 52 ng/10⁸ platelets. In fractioning experiments we found 95% of the serotonin in the hyalomer fractions and only 5% of the serotonin in the granulomer fractions. In vivo therefore, the high concentration of the serotonin is found almost exclusively in the hyalomer of the thrombocytes.

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Die Ergebniss wurden vor der Medizinischen Gesellschaft Düsseldorf am 23. 1. 1963 mitgeteilt. Herrn Prof. Dr.Meessen danken wir für die Anregung und Förderung der Arbeit, Herrn Prof. Dr.Greeff für die Hilfe bei den Serotoninbestimmungen.     

VAP-1: an adhesin and an enzyme

Leukocyte extravasation from the blood into tissues is of paramount importance for normal immunosurveillance and in mounting adequate inflammatory responses. Multiple traditional adhesion molecules and chemoattractants on leukocytes and endothelial cells are involved in the emigration process. Vascular adhesion protein 1 (VAP-1) is a nonclassical inflammation-inducible endothelial molecule involved in leukocyte-subtype-specific rolling under physiological shear. Molecularly, VAP-1 belongs to a special class of cell surface amino oxidases. The enzymatic reaction itself and the biologically active end products can potentially regulate the adhesive status of the vessel wall. Thus, VAP-1 is an ectoenzyme that has inter-related adhesive and enzymatic functions in regulating physiological trafficking and inflammation.     

Atherosclerosis as an autoimmune disease: an update.

Immunoinflammatory processes are discussed increasingly as possible pathogenic factors for the development of atherosclerosis. Here, we summarize the data on which we have built our immunological hypothesis of atherogenesis. This concept is based on the observation that almost all humans have cellular and humoral immune reactions against microbial heat-shock protein 60 (HSP60). Because a high degree of antigenic homology exists between microbial (bacterial and parasitic) and human HSP60, the 'cost' of immunity to microbes might be the danger of cross-reactivity with human HSP60 expressed by the endothelial cells of stressed arteries. Genuine autoimmunity against altered autologous HSP60 might trigger this process also.     

Development of an artificial synapse using an electrochemical micropump

Improving the resolution of artificial sensory organs requires an interface that receives external information from electronic circuits and stimulates appropriate neurons individually in response to that information. The method of electric stimulation in available artificial sensory organs is fairly nonselective; therefore, we developed a method of chemical stimulation of neurons using a neurotransmitter containing an electrochemical micropump powered by the bubbling that occurs during water electrolysis. The micropump contains a glass nozzle with a tip 10µm in diameter. Two blackened platinum electrodes for the electrolysis were inserted into the body of the pump, which was filled with neurotransmitter solution. The distance between a neuron of the gastropod Aplysia and the tip of the nozzle was adjusted to about 100µm. A potential difference of 3.0V was applied to the electrodes to propel the solution toward the neuron while its membrane potential was monitored. Administration of 1-mM acetylcholine to a resting neuron caused neural firing only when the voltage was applied for 0.5s and without a time lag. During administration of 50-mM -aminobutyric acid to spontaneously firing neurons, the firing disappeared with a time lag of 1s after application of 3.0V. We concluded that an electrochemical micropump can be applied for rapid neurotransmitter administration to control the excitation and inhibition of neurons. This simple pump can be miniaturized to create synapses in artificial sensory organs.     

Development of an RT-PCR diagnostic test for an avian astrovirus

Astroviruses are small round viruses that cause enteric disease in the young of several species. Detection and diagnosis of astrovirus infection in non-human hosts relies heavily on electron microscopy and fluorescent antibody tests. Recently, our laboratory isolated and sequenced an avian astrovirus from poult enteritis mortality syndrome affected turkeys. These studies describe the development of RT-PCR methods, which specifically detect regions of the viral capsid and polymerase genes, and demonstrate their use in detecting astrovirus infection in commercial turkey flocks.     

Achieving 95% uptake in an immunisation programme--not an impossibility

This study sought to document uptake rates achieved for vaccinations administered in a School Immunisation Programme in a school year. In a population of 6436 children uptake rates of more than 95% were achieved for all the vaccines administered, except MMR in the 6th class cohort for which 94.7% was the uptake figure. The success of the programme was attributed to the fact that the programme was the responsibility of a dedicated team, which facilitated the active follow-up of all defaulters as identified by the comprehensive database made available by the schools. Avoidance of deferral for minor illness was also a key factor.     

Esophageal tuberculosis: an unusual localization in an immunocompetent patient

Oesophageal tuberculosis is a rare localisation for extrapulmonary tuberculosis. This report describes the case of a 30-year-old immunocompetent woman with dysphagia, fever and weight loss. Endoscopic examination revealed an ulcerated lesion in the third part of the oesophagus strongly suggesting oesophageal carcinoma. Histologic samples showed epithelioid cells granuloma in the submucosa. Diagnosis was later confirmed by acid-fast bacilli positive gastric aspirates and a positive Mantoux test using the tuberculin reaction. Barium swallow revealed a narrowing in the third oesophagus. A chest x-ray revealed a infiltrated lesion and a mediastinal lymph node. The patient was put on antitubercular treatment. On follow-up after 3 months, dysphagia, fever, weight loss had disappeared and the ulcerated lesion of oesophagus had improved. The subsequent course of the patient is not known, since she was lost to follow-up.     

Pancreatic carcinoid: an unusual tumour in an uncommon location

Primary pancreatic carcinoid is an extremely rare pancreatic neoplasm. It differs from other primary pancreatic tumours in cytoarchitecture, immunocytochemistry and biologic behaviour. Recognition of this rare entity is of vital importance having considerable therapeutic and prognostic implications. We report a case of an exophytic, pancreatic body carcinoid tumour in a man who presented with abdominal pain. The diagnosis was established by histopathological examination of the core biopsy specimen. A surgical resection of the lesion was done successfully and the patient made a satisfactory recovery from the operation.     

Assessment of an undergraduate psychiatry course in an African setting

Background  

International reports recommend the improvement in the amount and quality of training for mental health workers in low and middle income countries. The Scotland-Malawi Mental Health Education Project (SMMHEP) has been established to support the teaching of psychiatry to medical students in the University of Malawi. While anecdotally supportive medical educational initiatives appear of value, little quantitative evidence exists to demonstrate whether such initiatives can deliver comparable educational standards. This study aimed to assess the effectiveness of an undergraduate psychiatry course given by UK psychiatrists in Malawi by studying University of Malawi and Edinburgh University medical students' performance on an MCQ examination paper.     

Metastatic angiosarcoma in an ileal conduit: an unusual presentation

The authors in this study describe the case of a patient with a history of multiple malignancies who underwent total cystectomy with ileal loop urinary diversion and presented with a lower extremity angiosarcoma on the background of lymphedema a decade later. Shortly thereafter, she was diagnosed with metastatic ileal conduit angiosarcoma. The authors state that to their knowledge, this is the first case of ileal conduit angiosarcoma reported in the English literature.     

Isolation of an unusual mycobacterium from an AIDS patient.

A mycobacterium isolated from a clinical sample of an AIDS patient was identified as Mycobacterium interjectum by direct 16S rRNA sequence determination. High-performance liquid chromatography, however, revealed a mycolic acid pattern which was different from the one shared by the previously analyzed strains of this species.     

Development of an immunoassay using an anti-wogonin glucuronide monoclonal antibody

Wogonin 7-O-β-D-glucuronide (Wgn) is a bioactive flavone present in the dried root of Scutellaria baicalensis Georgi. To generate a monoclonal antibody (MAb) against Wgn, BALB/c mice injected with Wgn–bovine serum albumin yielded splenocytes that we fused with SP2/0 myeloma cells using the polyethylene glycol method. We obtained a hybridoma designated 315A that produced a MAb reactive to Wgn. The anti-Wgn MAb 315A was applied to an indirect competitive enzyme-linked immunosorbent assay (icELISA) to quantify Wgn. Subsequent validation revealed that icELISA using the 315A anti-Wgn MAb is an accurate and reliable method for the quantification of Wgn in S. baicalensis.     

Social learning as an uncertainty-reduction strategy: an adaptationist approach

Social learning is an effective mechanism to reduce uncertainty about environmental knowledge, helping individuals adopt an adaptive behavior in the environment at small cost. Although this is evident for learning about temporally stable targets (e.g., acquiring avoidance of toxic foods culturally), the functional value of social learning in a temporally unstable environment is less clear; knowledge acquired by social learning may be outdated. This paper addressed adaptive values of social learning in a non-stationary environment empirically. When individual learning about the non-stationary environment is costly, a hawk-dove-game-like equilibrium is expected to emerge in the population, where members who engage in costly individual learning and members who skip the information search and free-ride on other members' search efforts coexist at a stable ratio. Such a "producer-scrounger" structure should qualify effectiveness of social/cultural learning severely, especially "conformity bias" when using social information (Boyd & Richerson, 1985). We tested these predictions by an experiment implementing a non-stationary uncertain environment in a laboratory. The results supported our thesis. Implications of these findings and some future directions were discussed.