Further freeze-fracture studies on the uterine epithelium of Salamandra salamandra (L.) (Amphibia,Urodela) using the antibiotic filipin

Summary The apical portion of the uterine lining of the ovoviviparous fire salamander, Salamandra salamandra, was studied by the freeze-fracture technique in conjunction with the polyene antibiotic filipin. Filipin-sterol complexes were found in the luminal plasmalemma and in the membranes limiting the mucous secretory granules typical of this epithelium. In all females, but particularly in non-pregnant females, more or less discrete clusters of filipinsterol complexes were occasionally found overlying heavily affected secretory granules. The findings are discussed with regard to comparable results (Orci et al. 1980) based on the examination of collapsed and stretched urinary bladders of toads.We are indebted to Mrs. K. Ott for excellent technical assistance, to Miss E.S. MacLure for linguistic corrections and to Dr. J.E. Grady of the Upjohn Co., Kalamazoo, Michigan USA, for kindly providing the filipin     

Klinik und Genetik des Joubert-Syndroms

Joubert syndrome generally represents an autosomal recessive and rarely X-linked disorder characterized by hypotonia, an irregular breathing pattern, abnormal eye movements, ataxia, developmental delay and a complex mid-hindbrain malformation causing the molar tooth sign on magnetic resonance imaging (MRI). Many patients have additional features, with nephronophthisis, retinal dystrophy, coloboma and hepatic fibrosis representing the most frequent features. Due to its clinical variability and overlap with other syndromes, the term “Joubert syndrome and related disorders” (JSRD) was proposed. To date 10 genes are known to cause JSRD. The encoded proteins are localized to cilia, linking JSRD to other human ciliopathies.     

EFFECTS OF IONIC STRENGTH OF IMMERSION MEDIUM ON THE STRUCTURE OF PERIPHERAL NERVE MYELIN

A study of the effects of hypertonic solutions on the structure of peripheral nerve myelin reveals an expansion rather than a contraction of the layer spacing. This suggests the absence of "free" water between the myelin layers. Hypotonic solutions bring about a change in radial repeat period from 171 A to 250 to 270 A. These findings are of significance in relation to the structure of myelin.     

Molekulare Karyotypisierung in der klinischen Diagnostik

The term “molecular karyotyping” refers to the genome-wide analysis of copy number variations using arrays that cover the genome with genomic markers with varying density. Currently the main application is the investigation of patients with otherwise unexplained mental retardation and multiple congenital anomalies. Studies of such patients who remained without etiological diagnosis after conventional karyotyping, subtelomeric screening, and targeted molecular–cytogenetic studies for well-known microdeletion syndromes revealed chromosomal microaberrations in about 10% of cases and allowed the delineation of several new microdeletion and microduplication syndromes. Nevertheless, because of the large number of copy number polymorphisms, interpretation of unique findings needs thorough consideration.     

Trace Metals in Fleece Wool and Correlations with Yellowness

The presence of copper and iron in metal-doped wool has been shown previously to be associated with the production of free radicals and yellowing in photo-irradiated wool. In this study, the yellowness and trace metal content of 700 wool samples was measured to determine if photoyellowing, catalysed by metals, is a major determinant of the colour of fleece wool. Iron and copper content did not positively correlate with yellowness and yellower wool tended to have lower levels of these metals. Instead, a strong positive correlation of yellowness with the calcium, manganese and magnesium content was observed in yellow wools. High levels of calcium and magnesium is consistent with biofilm formation by Pseudomonas bacteria that have previously been associated with non-scourable staining of wool.     

Nichtinvasive molekulargenetische Methoden in der pränatalen Diagnostik

Work on the development of noninvasive prenatal tests to avoid risk to the fetus in traditional amniocentesis or chorion villus biopsy has been ongoing for many years. Until recently, most approaches were extremely expensive and limited only to selected applications, thus they failed to develop beyond a “proof-of-principle” status. This has changed radically as a result of the introduction of new sequencing methods, since initial studies have shown that fetal aneuploidies from maternal plasma DNA can be identified correctly. In addition, these techniques make it possible to establish even the mutation status of the fetus. While on the one hand this offers completely new options in prenatal diagnosis, progress of this kind is associated with significant ethical challenges on the other. This overview article presents the development of these new methods.     

Die Genetik der bipolaren Störung

With a life-time prevalence of about 0.5–1.5%, bipolar (manic depressive) disorder represents a common psychiatric disease. Family, twin, and adoption studies have consistently shown that genetic factors contribute to disease development. Genome-wide linkage studies have detected chromosomal regions that are very likely to harbor predisposing genes. Meta-analyses suggest, however, that the genetic contribution of the individual loci must be relatively small which could be one reason for the difficulties in identifying the genes responsible. Very recently, genome-wide association analyses, investigating hundreds of thousands of single nucleotide polymorphisms (SNPs) in phenotypically well-characterized patient and control cohorts, promise a major breakthrough in search of disease-associated genes.     

Genetik und Klinik der Hämophilie A und B

Haemophilia A and B are caused by various mutations in the factor VIII (FVIII) and factor IX (FIX) genes, respectively. The clinical course of the disease is variable, dependent on the severity of the molecular defect. Nowadays, haemophilia patients can excellently be treated by plasma-derived or recombinant clotting factor concentrates. Thus, bleeding and its consequences can be almost completely prevented with nearly normal quality of life and life expectancy. The most severe complication of this treatment is the formation of antibodies (inhibitors) against the substituted clotting factor. The risk of inhibitor formation correlates significantly with specific mutation types that preclude endogenous factor VIII/IX protein synthesis and can be as high as 20–50%. The information on the expected clinical course is at present the most important indication for FVIII/IX gene analysis. Knowledge of the underlying FVIII/IX gene mutation further allows a reliable and fast carrier diagnosis in female relatives of patients with haemophilia.