1,720,976 research outputs found
Studio del comportamento intracellulare di Legionella pneumophila ed altri batteri acquatici in Acanthamoeba polyphaga
No full textIn questo studio si è ritenuto interssante valutare le interazioni tra alcuni batteri ad habitat idrico e un ceppo di Acanthamoeba polyphaga, al fine di comprendere meglio il ruolo di tali microrganismi nell'ecologia di L.pneumophila
Decreased fibrosis in aorta of salt loaded stroke-prone spontaneously hypertensive rats by combining delapril and indapamide treatments: a dose response analysis.
No full textThe protective effects of the angiotensin-converting enzyme (ACE) inhibitor delapril and the diuretic indapamide were investigated in stroke-prone spontaneously hypertensive rats (SHRsp) by studying vascular wall fibrosis in the thoracic aorta
Static and dynamic osteogenesis: two different types of bone formation
No full textThe onset and development of intramembranous ossification centers in the cranial vault and around the shaft of long bones in five newborn rabbits and six chick embryos were studied by light (LM) and transmission electron microscopy (TEM). Two subsequent different types of bone formation were observed. We respectively named them static and dynamic osteogenesis, because the former is characterized by pluristratified cords of unexpectedly stationary osteoblasts, which differentiate at a fairly constant distance (28+/-0.4 mum) from the blood capillaries, and the latter by the well-known typical monostratified laminae of movable osteoblasts. No significant structural and ultrastructural differences were found between stationary and movable osteoblasts, all being polarized secretory cells joined by gap junctions. However, unlike in typical movable osteoblastic laminae, stationary osteoblasts inside the cords are irregularly arranged, variously polarized and transform into osteocytes, clustered within confluent lacunae, in the same place where they differentiate. Static osteogenesis is devoted to the building of the first trabecular bony frame-work having, with respect to the subsequent bone apposition by typical movable osteoblasts, the same supporting function as calcified trabeculae in endochondral ossification. In conclusion, it appears that while static osteogenesis increases the bone external size, dynamic osteogenesis is mainly involved in bone compaction, i.e., in filling primary haversian spaces with primary osteons
Cell-matrix interactions in cultured dermal fibroblasts from patients with an inherited connective-tissue disorder
No full textIndirect-immunofluorescence studies were performed on cultured dermal fibroblasts from patients with Pseudoxanthoma Elasticum (PXE), an inherited connective-tissue disorder the pathogenesis of which is still unknown. Apparent abnormalities of cytoskeletal structures were revealed by using phalloidin and specific antibodies to alfa-smooth muscle actin and to vimentin. Altered expression of integrin receptors for different extracellular matrix components seems to be present in the pathological cells as preliminary data suggest by using antibodies against alfa subunits of integrins. This study was designed to test the presence of abnormal cell-matrix interactions responsible for the clinical features and involved in the pathogenesis of the PXE disease
STRUCTURE AND COMPOSITION OF THE ELASTIN FIBER IN NORMAL AND PATHOLOGICAL CONDITIONS
No full textElastin fibres are present in all connective tissues of vertebrates, and are particularly abundant in those undergoing physiological mechanical stress. Elastin, the main component of the fibres, is secreted as soluble tropoelastin molecules, that are crosslinked into insoluble aggregates in the extracellular space. Tropoelastin is highly hydrophobic and is encoded by a single copy gene, localized on chromosome 7 in humans; the primary transcript undergoes alternate splicing giving rise to different tropoelastin molecules, whose distribution and physiological significance are still under investigation. Elastin shows a transient developmental expression, with barely detectable turnover during adult life. In thin sections, elastin fibres appear rather compact and consist of an amorphous material (true elastin) and of longitudinal strips, probably made of various components. By freeze-fracture and negative staining, the elastin fibre has been shown to be made of a loose irregular network of beaded filaments, which can be oriented by stretching. Cytochemical and immunocytochemical approaches have shown that elastin fibres contain proteoglycans as well as sites recognized by antibodies to lysyl oxidase and microfibrillar components. It has been suggested that microfibrils and proteoglycans might have a role in elastin fibrogenesis. Elastin fibres undergo irreversible alterations during aging and in pathological conditions. These alterations consist mainly of accumulation of ions and of abnormal matrix constituents, and/or swelling and disaggregation of the fibre itself
Biochemical and morphometric studies of the aortic extracellular matrix in long term hypertension: Effects of diet and anti-hypertensive drugs
No full textThe investigation was aimed to characterize long term changes in the aortic wall composition related to hypertension and drug admnistration
Time-course of protective effects on the aorta wall by treatment with delapril, indapamide and their combination in stroke-prone spontaneously hypertensive rats (SHRsp)
No full textThe investigation was aimed at characterizing long term changes in the aorta wall structure in hypertensive rats
Effect Of Selective Enzymatic Digestions On Skin Biopsies From Pseudoxanthoma Elasticum - An Ultrastructural-Study
No full textAntimicrobial properties and morphological characteristics of two Photorhabdus luminescens strains
No full textThe biological properties of two Photorhabdus luminescens isolates (MU1 and MU2) of environmental source and the activity of antimicrobial agar diffusible agents (AADA) produced by the same are reported. With regard to cultural features, two variant forms for P. luminescens MU1 and three for P. luminescens MU2 (including an intermediate phase I-like form) have been found. These three forms differ in biological and biochemical properties: P-lactamase, urease, bioluminescence and antimicrobial agar diffusible substance production associated with the phase I form, were less evident in the intermediate phase I-like MU2 and were absent in phase II form. Antimicrobial activity was present in both strains, with the production of a large amount of a diffusible compound with a wide spectrum of action against bacteria of other genera; a reduced activity against correlated species was also observed. Examination by electron microscopy of MU1 and MU2 purified broth cultures revealed the presence of particles belonging to the class of the phage tail-like bacteriocins, described in recent studies as responsible for antibacterial activity against correlated bacteria, a result never confirmed in vitro. A plasmid of 21 Mdal was observed in all the form variants of P. luminescens MU2, suggesting that plasmids are not involved in the transition from primary to secondary phase; no plasmid was detected in P. luminescens MU1
Histomorphometric, biochemical and ultrastructural changes in the aorta of salt-loaded stroke-prone spontaneously hypertensive rats fed a Japanese-style diet
No full textBackground and Aim: It is demonstrated that dietary habits play a role in cardiovascular diseases. In stroke-prone spontaneously hypertensive rats ( SHRsp), concomitant salt loading and a Japanese-style diet greatly accelerate hypertension and the appearance of cerebrovascular lesions by directly damaging arterial vessels. A number of studies have characterised medium and small vessel lesions in SHRsp, but little attention has been paid to the changes in the wall structure of large arteries induced by exposure to a salt-enriched diet. The aim of this study was to investigate the effects of a Japanese-style diet and salt loading on the thoracic aorta. Methods and Results: Two-month-old SHRsp were kept on a Japanese-style diet with 1% sodium chloride solution replacing tap water. Two months later, they were sacrificed and compared with age-matched or two-month-old control SHRsp kept on a standard diet and tap water in terms of the histomorphometry; ultrastructure and biochemical composition of the thoracic aorta. The vessel was consistently thicker in the four-month-old SHRsp (+20%, p<0.05 vs two-month-old rats) regardless of diet The salt-loaded SHRsp showed a significant reduction in elastic fibre density (-20%, p<0.05 vs two-month-old rats) and art increase it? the other matrix components (+50%), whereas the four-month-old controls showed preserved elastic fibres and a significant increase in the other matrix components (+65%, p<0.05 vs two-month-old rats). There was a considerable increase in the amounts of 4-OH-proline (+147%), 5-OH-lysine (+174%) and desmosines (+360%) in the four-month-old controls vs their two-month-old counterparts (p<0.01), but not in the salt-loaded animals. Ultrastructural analysis revealed clear damage and accelerated aging in the thoracic aorta of the salt-loaded SHRsp. Conclusions: Salt loading and a Japanese-style diet destabilise thoracic aorta architecture in SHRsp after two months of treatment
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