Light and electron microscopic studies onMyxobolus cotti El-Matbouli and Hoffmann, 1987 infecting the central nervous system of the bullhead (Cottus gobio)

Myxobolus cotti (Myxozoa: Myxosporea) is described as found in the central nervous system of the bullhead (Cottus gobio) caught in the Alpine lake Königssee and in a brook in the Bavarian Forest, Federal Republic of Germany (El-Matbouli and Hoffmann 1987). Aggregations of spores and polysporoblastic trophozoites compressed and replaced large areas of the white and grey matter of the brain and spinal cord. These aggregations may be surrounded by a thin, connective tissue capsule; in a few cases they were associated with loose infiltrates of glial cells. Neither conspicuous tissue reactions nor inflammatory responses were evident. No other organs were seen to be infected withM. cotti. Mature spores are oval, with a tapering anterior end, and the pyriform polar capsules are nearly equal in size. Fresh spores measured 8.9–15.1 m in length (mean, 12.4 m) and 8–12.4 m in width (mean, 9.6 m); polar capsules were 4.3–9 m long (mean, 6.4 m); and 2–3.8 m wide (mean, 2.9 m). Light microscopy, the ultrastructure of pansporoblasts, sporogenesis and mature spores are described.     

Morphological detection and quantification of lipoprotein(a) deposition in atheromatous lesions of human aorta and coronary arteries

Summary Lipoprotein(a), as an atherogenic particle, represents an independent risk factor for coronary heart disease. In the present study the morphological distribution of apoprotein (a) and apoprotein B within the arterial wall is described. Apoprotein B, a constituent of very low-density lipoprotein, low-density lipoprotein and lipoprotein(a) has previously been demonstrated in atheromatous lesions. Lipoprotein(a) possesses an additional protein, designated apoprotein (a). Autopsy material (n=74) from the left coronary artery and from the thoracic aorta has been examined by means of immunohistochemistry and both apoprotein (a) and apoprotein B were detected, primarily associated with the extracellular matrix and accumulating in lesions in the arterial wall. The staining pattern for both antigens was almost always found to be congruent, suggesting that the detection of (a)-antigen has to be attributed at least in part to the presence of lipoprotein(a). It is concluded that both low-density lipoprotein and lipoprotein(a) have an important role in the pathogenesis of atherosclerosis.     

Unrestricted recognition of class I neodeterminants generated by exon shuffling

We and others have previously reported that homologous exchange of alpha 1 or alpha 2 domains between different alleles led to loss of most determinants recognized by cytotoxic T lymphocytes (CTL) raised against the parental H-2 class I antigens. Here we demonstrate that exchange of alpha 1 or alpha 2 domains between the Kk and Kd allele results in the formation of neodeterminants against which allospecific CTL can be generated in responder mice of various related and unrelated H-2 haplotypes. In fact, only CTL against the neodeterminants on the hybrid molecules were found and none against the parental Kk and Kd determinants. In addition our data show that recognition of the neodeterminants is H-2 unrestricted. These findings suggest that in the hybrid molecules the basic structure of a major histocompatibility complex molecule has been preserved although most parental allodeterminants on the alpha 1 and alpha 2 domains have been modified.     

Recent developments in molecular action of antihormones

 Antihormones are by definition antagonists of steroid hormone action. They interact with the ligand binding domains of steroid hormone receptors and competitively inhibit the action of the receptors by mechanisms that are not quite understood. In certain cases antihormones also exhibit agonistic activity especially in connection with certain naturally occurring receptor mutants. These observations together with findings of indiscriminate interaction of antihormones with several classes of steroid receptors have necessitated a search of more effective and reliable antihormones. Recent advances in the resolution of the crystal structure of the ligand binding domains of certain members of the steroid receptor family and identification of non-liganded activation of steroid receptors have produced considerable information that can be harnessed into a fruitful search for a new generation of antihormones. Received: 19 June 1997 / Accepted: 10 October 1997     

Autoimmunity and inflammation due to a gain-of-function mutation in phospholipase C gamma 2 that specifically increases external Ca2+ entry

The identification of specific genetic loci that contribute to inflammatory and autoimmune diseases has proved difficult due to the contribution of multiple interacting genes, the inherent genetic heterogeneity present in human populations, and a lack of new mouse mutants. By using N-ethyl-N-nitrosourea (ENU) mutagenesis to discover new immune regulators, we identified a point mutation in the murine phospholipase Cg2 (Plcg2) gene that leads to severe spontaneous inflammation and autoimmunity. The disease is composed of an autoimmune component mediated by autoantibody immune complexes and B and T cell independent inflammation. The underlying mechanism is a gain-of-function mutation in Plcg2, which leads to hyperreactive external calcium entry in B cells and expansion of innate inflammatory cells. This mutant identifies Plcg2 as a key regulator in an autoimmune and inflammatory disease mediated by B cells and non-B, non-T haematopoietic cells and emphasizes that by distinct genetic modulation, a single point mutation can lead to a complex immunological phenotype.     

Sex- and age-related blood pressure response to dynamic work with small muscle masses

Summary Four groups of subjects of different ages and sex (group I: 20–29 years, women; group II: 20–29 years, men; group III: 30–39 years, women; group IV: 30–39 years, men) undertook dynamic one-hand work (load range 40%–80% of maximum voluntary contraction, at 60 working cycles/min) to allow a study of cardiovascular responses as shown by the resultant changes in blood pressure and heart rate. During fatiguing dynamic one-hand work, there was a large increase in systolic and diastolic blood pressures in both sexes after a few minutes. For all load levels, the systolic blood pressure was found to be higher by about 4 kPa in men (groups II and IV) than in women (groups I and III). Other age-related differences became evident in the diastolic blood pressure changes. The values obtained for the older groups were higher than those in the two younger groups. These differences in blood pressure response are possibly due to sex-related differences in the release of catecholamines, or to age-related organic changes in the vessels.     

Ultrastructure of the gastric mucosa harboring Campylobacter-like organisms

The association between Campylobacter-like organisms (CLOs) and lesions of the gastric mucosa was studied in 59 consecutive biopsies. Hematoxylin and eosin and Warthin-Starry silver stains, as well as high-resolution light microscopy (HRLM) and transmission electron microscopy (TEM), were used. The organisms were found in intimate contact with foveolar cells showing abundant phagolysosomes and alterations of the intercellular complexes. CLOs also were seen in close proximity of parietal cells in resting phase, some of which showed degenerative changes. The findings are discussed in light of recent reports linking CLOs to the cause of gastritis.