1,720,962 research outputs found
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
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
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
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
The effect of caloric restriction on the aortic tissue of aging rats
No full textConnective tissue shows peculiar and complex age-related modifications, which can be, at least in part, responsible for altered functions and increased susceptibility to diseases. Food restriction has long been known to prolong life in rodents, having antiaging effects on a variety of physiologic and pathologic processes. Therefore, the aorta has been investigated in rats fed normal or hypocaloric diet, from weaning to senescence. Compared with controls, caloric-restricted animals showed less pronounced age-dependent alterations such as elastic fiber degradation, collagen accumulation and cellular modifications. Immunocytochemical analyses revealed that elastic fibers were positively labelled for biglycan, decorin, ApoB100 (LDL), ApoAl (HDL) and elastase and that the intensity of the reactions was time- and diet-dependent, With age, the major changes affecting aortic elastic fibers were increased positivity for decorin, LDL and elastase, Compared with age-matched normal fed rats, caloric restricted animals revealed lower content of LDL, decorin and elastase and higher positivity for HDL. These data suggest that a caloric restricted diet might influence the aging process of the arterial wall in rats, delaying the appearance of age-related degenerative features, such as structural alterations of cells and matrix and modified interactions of elastin with cells and with other extracellular matrix molecules
Dose-Dependent Prevention of Fibrosis in Aorta of Salt-Loaded Stroke-Prone Spontaneously Hypertensive Rats by Combined Delapril and Indapamide treatment.
No full textCombined treatment with the angiotensin-converting enzyme (ACE) inhibitor delapril and the diuretic indapamide prevented vascular damage in vital organs of salt-loaded stroke-prone spontaneously hypertensive rats (SHRsp). Whether the changes occurring after long-term hypertension could also be modulated in large arteries was investigated. Two-month-old SHRsp were salt loaded and treated with the drug regimen until they reached 50 +/- 10 mortality or around midlife. In a first experiment, delapril (12 mg/kg) and indapamide (1 mg/kg) were administered daily separately or in combination. In the second dose-finding experiment, delapril (6, 3, 1.5 mg/kg) and indapamide (0.5, 0.25, 0.125 mg/kg) in decreasing dose combinations were analyzed. Ultrastructural, histomorphometric, and biochemical studies were performed on the thoracic aorta. When compared with delapril (12 mg/kg) or indapamide (1 mg/kg) administered individually for 5 months, the combination 12 + 1 mg/kg was able to prevent the increase in extracellular matrix deposition observed in other treatment groups, as assessed by histomorphometry or 4-OH-proline biochemical determination. In the second experiment, a half-dose (delapril 6 mg/kg + indapamide 0.5 mg/kg) combination was similarly effective in counteracting fibrosis, but the other doses progressively failed. In the first experiment, the combination had a stabilizing effect on hypertension and stimulated diuresis. In the second experiment, arterial blood pressure values and sodium balance were not consistently affected by the treatments that antagonized fibrosis (i.e., delapril 6 mg/kg + indapamide 0.5 mg/kg and, less efficiently, delapril 3 mg/kg + indapamide 0.25 mg/kg). These results suggest that indapamide interacts with ACE inhibitors to limit aortic fibrosis independent of any well-established mechanism
Identification of heterozygote carriers in families with a recessive form of pseudoxanthoma elasticum (PXE)
No full textSkin biopsies of 18 healthy relatives of patients with pseudoxanthoma elasticum (PXE), belonging to six different recessive families, have been examined by optical and electron microscopy in order to determine morphologic alterations potentially useful for the identification of carriers of this genetic disorder. These morphologic features have been compared with those observed in the same tissue areas of eight PXE patients belonging to the same families, with six normal subjects, and to the carrier status of these apparently unaffected relatives as determined by haplotype analysis using informative markers surrounding the locus of the PXE gene on chromosome 16p. The dermis of all the relatives of PXE patients, established by haplotype analysis to be heterozygote carriers of a mutation in the PXE gene, exhibited several alterations very similar, although less severe, to those typical in PXE patients. Alterations were present in the reticular dermis and consisted of irregular-sized collagen bundles and elastic fibers; elastic fibers fragmented, cribriform, and mineralized; numerous fibroblasts, larger than normal, and subendothelial elastin in small vessels. Strikingly, none of these dermal changes were noted in an unaffected relative in one family who was identified as a noncarrier by haplotype analysis. Although many of these alterations are not specific for PXE, the presence of these morphologic changes in unaffected relatives of PXE patients indicates alterations in skin that could be diagnostic for carriers of a subclinical phenotype of PXE
The placenta in pseudoxanthoma elasticum: clinical, structural and immunochemical study.
No full textPseudoxanthoma elasticum (PXE) is a rare genetic disorder clinically characterized by skin, cardiovascular and eve manifestations, mainly due to calcification and fragmentation of elastic fibres. although infrequent, complications during pregnancy in nomen affected by PXE have been reported. The aim of the present stud! was to compare structural features of placentae at term from 14 control and 15 PXE-affected nomen, in order to better understand if and hen: abnormal mineral and/or matrix accumulation might affect placental function in PSE. In all cases, pregnancy, fetus growth and delivery were normal. Both gross and light microscopy examination did not reveal dramatic differences between placentae of PSE patients and controls, with regard to weight, dimensions, infarcts, thrombi, inflammatory lesions or vessels. However, necrotic changes and mineralization appealed statistically more pronounced in PXE. By electron microscopy the most remarkable differences between PXE and control placentae were observed in the localization and morphology of mineral precipitates; a significant higher deposition of mineral precipitates was observed associated with the ́matrix ́-type fibrinoid and among collagen fibrils, especially on the maternal side. Immunocytochemistry revealed the presence of vitronectin and fibronectin associated with the PXE-specific mineralizations and the absence of mineralization on the small and scarce elastic fibres in either controls or in PXE
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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