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.     

Immunolocalization of lamins and nuclear pore complex proteins by atomic force microscopy

The nuclear envelope functions as a selective barrier separating the nuclear from the cytosolic compartment. Nuclear pore complexes (NPCs) mediate nuclear import and export of macromolecules and, therefore, are potential regulators of gene expression. In this study we applied atomic force microscopy (AFM) to visualize the three dimensional (3D) structure of individual NPCs in the absence and presence of two different antibodies, one directed against a pore protein (gp62) and another directed against Xenopus lamin LIII, a component of the nuclear lamina, a filament meshwork localized on the nucleoplasmic side of the nuclear envelope (NE) adjacent to and interacting with NPCs. Using 12-nm gold-labelled secondary antibodies and transmission electron microscopy we could clearly localize the primary single anti-gp62 antibody on NPCs and the primary single anti-LIII antibody between NPCs. Using AFM, the secondary antibodies against anti-gp62 could be detected as particles 7 nm in height on the nucleoplasmic face of NPCs. The secondary antibodies against anti-LIII could be clearly identified between NPCs. The secondary antibodies, attached to a 12-nm colloidal gold particle and visualized on glass, revealed similar shapes and heights as found on NEs. According to the 3D images, the volume of a single gold particle conjugated with secondary antibodies was 10 203 nm³. This volume is equivalent to the volume of 38 IgG molecules associated with one individual gold particle. A similar volume of 11 987 nm³ was calculated from a model assuming that the 150-kDa IgG molecules perfectly cover the spherical gold particle. We conclude that AFM can be used for identifying antibodies or other macromolecules associated with biomembranes.     

Adhesion of carcinoma cells to rat hepatocytes and rat fibronectin is inhibited by the OPAR monoclonal antibody,which is directed against a rat liver-specific carbohydrate epitope

The OPAR mouse monoclonal antibody (mAb) directed against rat hepatocytes was previously shown to inhibit adhesion of TA3/Ha mammary carcinoma cells to hepatocytes. The antigen is abundantly present at the surface of hepatocytes beneath the endothelium of liver capillaries where we have observed invasion of carcinoma cells to occur. The OPAR mAb reacted with three major bands on a Western blot of liver plasma membrane proteins. The same proteins were also seen upon immunoprecipitation from iodinated liver plasma membrane proteins. We have isolated OPAR antigens by lectin wheat germ agglutinin (WGA) and OPAR affinity chromatography. Amino acid sequence analysis revealed that two of the bands were 1-macroglobulin and C4-binding protein, which are serum components produced by hepatocytes. The presence of the epitope on distinct proteins and our previous observation that it can be detected in the Golgi apparatus but not in the endoplasmic reticulum, suggested that OPAR reacts with a liver-specific glycoconjugate. Loss of OPAR reactivity after neuraminidase and N-glycosidase F treatment showed that the epitope contains sialic acid residues on N-linked sugar moieties. OPAR also reacted with rat fibronectin, and inhibited adhesion of TA3/St cells to fibronectin. This explains the inhibition by the OPAR mAb of TA3/St cell adhesion to hepatocytes, which we have shown to be due mainly to interaction with hepatocyte surface-associated fibronectin. However, adhesion of the related TA3/Ha cells to hepatocytes, which is mediated by the ₆P4 integrin, and does not involve binding to fibronectin, is also inhibited. This suggests that ₆₄ on liver-metastasizing carcinoma cells binds to an OPAR epitope-carrying glycoprotein produced by hepatocytes.     

Three new families with arterial tortuosity syndrome

Arterial tortuosity syndrome (ATS) is a rare condition with autosomal recessive inheritance characterized by connective tissue abnormalities. The most specific clinical findings are cardiovascular anomalies including tortuosity, lengthening, aneurysm, and stenosis formation of major arteries. Also ventricular hypertrophy is frequently present. Other anomalies are skin hyperextensibility and cutis laxa, joint laxity or contractures of the joints, and inguinal herniae. Histology shows disruption of elastic fibers of the media. These features suggest that ATS is a connective tissue disorder. A biochemical or molecular defect has not yet been identified. We describe here nine additional ATS patients from three consanguineous Moroccan families and review a total of 35 patients with this uncommon condition.     

Congenital malformation of the feet with low body height

Among 75 members of a Danish family, 12 were found with a syndrome not previously described. Clinically, the syndrome consists of low body height and rigid flat feet, with weight-bearing pain in the feet. Radiologically, the deformation of the feet is a medial synostosis between the talus and the calcaneus combined with ankle joint dysplasia. The cause of the syndrome is most probably an autosomal dominant gene with complete penetrance. No linkage was found of the gene to 18 marker genes.     

Age-related accumulation of congophilic fibrillar inclusions in endocrine cells

Summary Intracellular fibrillar congophilic inclusions are well known as neurofibrillary tangles in neurons and as Biondi bodies in choroid plexus epithelial cells. Recently similar amyloid-like inclusions in adrenal cortical cells were described (Eriksson and Westermark 1990). This study on 150 adrenal glands confirms these observations. In our material the age-related accumulation of congophilic inclusions starts earlier (in the sixth decade) and reaches a higher incidence (42.7%). We found similar intracellular inclusions in other endocrine organs, for example in the anterior lobe of the pituitary, in the cells of parathyroid glands and in Sertoli cells. The age-related incidence of these fibrillar inclusions in the pituitary was 68%; the co-incidence with interstitial amyloid deposits was 49.5%. Thus the intracellular accumulation of congophilic fibrils in old age is a widespread phenomenon and occurs not only in neurons but also in endocrine cells (adrenal, pituitary and parathyroid glands) and in active secretory cells (choroid plexus and Sertoli cells).     

Beeinflussung der Atemsteigerung bei Muskelarbeit durch partiellen neuromuskulären Block (Tubocurarin)

Zusammenfassung In 17 Versuchen erhielten 7 Versuchspersonen 0,09–0,16 (Mittel 0,13) mg Tubocurarin/kg i.v. Vor und nach der Injektion wurde die gleiche Muskelarbeit geleistet (Beinarbeit; O₂-Aufnahme etwa das dreifache des Ruheumsatzes). Gemessen wurden Atemzeitvolumen, alveolarer O₂- und CO₂-Druck, Blutdruck und Pulsfrequenz. Die Curaredosen führten zu einer Erschwerung der Arbeit, beeinträchtigten jedoch nicht die Atmung.Bei gleicher Muskelarbeit ventilierte die Mehrzahl der Versuchspersonen, vor allem im Beginn der Arbeit, unter Curare mehr als bei der Kontrollarbeit ohne Curare. Am deutlichsten war dies bei denjenigen Versuchspersonen ausgeprägt, die schon ohne Curare im Beginn der Arbeit eine plötzliche Steigerung der Ventilation zeigten.Es wird angenommen, daß unter Curare die gleiche Muskelarbeit mit einer verstärkten motorischen Innervation geleistet wird. Die dabei beobachtete Ventilationssteigerung wird als weiteres Argument für einen Einfluß der motorischen Innervation auf die Atemzentren angesehen.Mit 3 TextabbildungenHerrn Professor Dr. Hans Winterstein zum 80. Geburtstag gewidmet.     

HLA-DR2 in two sibships with insulin-dependent diabetes mellitus.

We report two families selected from 124 genotyped Caucasian insulin-dependent diabetes mellitus (IDDM) families because of unusual features. In both families, all offspring are affected and four out of six bear the allele HLA-DR2 which is an uncommon phenotype among diabetic patients. Onset before the age of 1 year in all the patients of one family, association with optic atrophy in the other, and the existence of pairs of affected sibs of different HLA types in both, are infrequent findings and support the evidence of heterogeneity in IDDM.