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At least 487 records · Page 27Linked to original sources
PubMed2000

Ovarian steroid and cytokine modulation of human endometrial angiogenesis.

A key mechanism underlying the cyclical growth of the endometrium is its ability to regenerate a vascular capillary network. In normal cycling human endometrium, angiogenesis is influenced by both endocrine and paracrine factors. Hormonal manipulation of the endometrium, such as that occurring during the use of steroidal contraception, appears to result in capillary proliferation and fragility. As a consequence of these vascular changes, contraceptive users may be predisposed to unpredictable uterine bleeding, which is responsible for the high frequency of contraceptive discontinuation. In this paper we address mechanisms responsible for vascular endothelial cell proliferation in normal and contraceptive steroid-exposed endometria. We propose that regulation of endometrial angiogenesis is mediated indirectly, via steroid and cytokine actions on vascular endothelial growth factor (VEGF), and we present data indicating that VEGF expression in normal endometrial stromal cells is increased by oestrogens and progestins. Three proinflammatory cytokines with angiogenic effects in other systems (i.e. interleukin-1beta, tumour necrosis factor-alpha and interferon-gamma) do not appear to up-regulate VEGF expression in normal endometrial stromal cells. Well-characterized in-vitro models in conjunction with immunohistochemistry provide useful experimental systems to study endometrial neovascularization under physiological conditions and in those potentially perturbed via the use of contraceptive steroids.

Biopsy↗
PubMed1985

Zinc deficiency dermatitis in parenteral nutrition: an electron-microscopic study.

Two cases of zinc deficiency dermatitis (acute phase) on parenteral nutrition are reported. Subepidermal blisters caused by a decrease in the number of desmosomes and hemidesmosomes located between the discontinuous basal membrane and cell membranes are shown. The collagen fibers presented changes which probably are responsible for the breaking or fragility of the capillaries. These facts went unnoticed in previous studies.

Acute Disease↗
PubMed2004

Flavonoids from Argentine Tagetes (Asteraceae) with antimicrobial activity.

The flavonoids, constituting one of the most numerous and widespread groups of natural plant constituents, are important to humans not only because they contribute to plant colors but also because many members are physiologically active. These low-molecular-weight substances, found in all vascular plants, are phenylbenzopyrones. Over 4000 structures have been identified in plant sources, and they are categorized into several groups. Primarily recognized as pigments responsible for the autumnal burst of hues and the many shades of yellow, orange, and red in flowers and food, the flavonoids are found in fruits, vegetables, nuts, seeds, stems, flowers, and leaves as well as tea and wine and are important constituents of the human diet. They are prominent components of citrus fruits and other food sources. Flavonols (quercetin, myricetin, and kaempferol) and flavones (apigenin and luteolin) are the most common phenolics in plant-based foods. Quercetin is also a predominant component of onions, apples, and berries. Such flavanones as naringin are typically present in citrus fruit, and flavanols, particularly catechin, are present as catechin gallate in such beverages as green or black tea and wine. Some major sources of flavonoids are outlined in Table 1. The daily intake of flavonoids in humans has been estimated to be approx 25 mg/d, a quantity that could provide pharmacologically significant concentrations in body fluids and tissues, assuming good absorption from the gastrointestinal tract. Biological activity of flavonoids was first suggested by Szent-Gÿorgyi 1938, who reported that citrus peel flavonoids were effective in preventing the capillary bleeding and fragility associated with scurvy. The broad spectrum of biological activity within the group and the multiplicity of actions displayed by a certain individual members make the flavonoids one of the most promising classes of biologically active compounds.

Anti-Infective Agents↗
PubMed2000

Oligomeric proanthocyanidin complexes: history, structure, and phytopharmaceutical applications.

Considerable recent research has explored therapeutic applications of oligomeric proanthocyanidin complexes (OPCs), naturally occurring plant metabolites widely available in fruits, vegetables, nuts, seeds, flowers, and bark. OPCs are primarily known for their antioxidant activity. However, these compounds have also been reported to demonstrate antibacterial, antiviral, anticarcinogenic, anti-inflammatory, anti-allergic, and vasodilatory actions. In addition, they have been found to inhibit lipid peroxidation, platelet aggregation, capillary permeability and fragility, and to affect enzyme systems including phospholipase A2, cyclooxygenase, and lipoxygenase. Based on these reported findings, OPCs may be a useful component in the treatment of a number of conditions.

Anthocyanins↗
PubMed2001

[Clinical manifestations of AL-amyloidosis and some other types of amyloidosis].

Amyloidosis is the term for specific pathological peptide deposits in various tissues. Amyloid substances may be the manifestation of the following nosological units: AL-amyloidosis, AA-amyloidosis, ATTR-amyloidosis, beta2-microglobulin amyloidosis and possibly othr familiar forms of amyloidosis. The most frequent symptoms of amyloidosis are: 1. proteinuria with nephrotic syndrome, 2. cardiac failure with restrictive cardiomyopathy, 3. unexplicable hepatomegaly, 4. idiopathic peripheral polyneuropathy, 5. haemorrhagic manifestations and symptoms of increased fragility of the capillaries while the number of thrombocytes is normal, 6. periorbital haematomas and 7. macroglossia. Diagnostic and therapeutic procedures differ according to the type of amyloidosis and are analyzed in detail in the text.

Amyloidosis↗
PubMed2000

Extensive haemorrhagic-bullous skin manifestation of systemic AA-amyloidosis associated with IgGlambda-myeloma.

In an 86-year-old woman with a multiple myeloma of the IgG lambda subtype a coinciding systemic amyloidosis manifested as a macroglossia, diffuse alopecia and generalized cutaneous involvement. The skin was affected by milium-like papules, petechial haemorrhages and an increased tissue fragility with subsequent blister formation. The typical histology and immunohistology pattern revealed large intradermal amyloid masses, reacting positively with anti-amyloid A antibodies, which surrounded cuff-like dilatated blood capillaries. The abundance of these amyloid deposits led to significant deflexibilization and fragility of the capillaries and the dermal matrix eventually resulting in the haemorrhagic-bullous eruptions. The peculiar feature of the present case is the intensity of bullous-haemorrhagic skin damage due to amyloid A deposition without any detection of cutaneous IgGl as the myeloma-derived paraprotein assumed to be causative for the development of systemic AA amyloidosis.

Aged↗
PubMed1990

Development of the vasculature of the pars distalis in a tumor-susceptible strain of rat (Fischer 344) differs from vascular development in a non-tumor-susceptible strain (Lewis).

The development of the vasculature of the pars distalis of two strains of rat, Fischer 344 (F344) and Lewis (LEW), was followed in 16-day (16d) and 20-day (20d) fetuses, and in 1-day (1d), 5d, 20d, 50d, and 6-month-old females. No differences in the two strains were apparent in 16d fetuses; and the capillaries that were present were immature, i.e., tall, non-fenestrated endothelial cells, and were surrounded by poorly delineated pericapillary spaces. Immature capillaries also were predominant in 20d fetuses of both strains. Agranular folliculo-stellate cells were identifiable, projecting endfeet to the parenchymal basal lamina in 20d F344 fetuses, but not in LEW fetuses. Postnatally, the capillaries of LEW rats became progressively more thin-walled and fenestrated, and were surrounded by a pericapillary space that was well delimited by basal laminae at 20d. In 50d and 6-month LEW rats, capillaries were intact and surrounded by well-defined pericapillary spaces. By comparison in F344 rats, the capillaries remained more immature even in 50d rats and older. In addition, in F344 rats focal disruptions in endothelial cells and disruptions in parenchymal and capillary basal laminae were present in all postnatal stages, and a dramatic accumulation of plasma was evident within the pericapillary spaces at 20d. Endfeet processes of folliculo-stellate cells were abundant at the parenchymal basal lamina of 1d and 5d F344 neonates, but only rarely were identified in LEW neonates. Some activation of folliculo-stellate cells, i.e., increased numbers of lysosomes and dilated endoplasmic reticulum, was present in 50d F344 rats. Connective-tissue cells within the pericapillary space also were numerous and activated in F344 rats. Discrete gaps in the parenchymal basal lamina were evident subjacent to the folliculo-stellate cell endfeet in F344 rats but not in LEW rats. The vascular bed of F344 rats differs in its development from that of LEW rats. Characteristic of the F344 strain is a persistence of more immature capillaries, an inherent vascular fragility, and an activated state of folliculo-stellate cells.

Animals↗
PubMed1984

Role of sulfhydryls and early vascular lesions in gastric mucosal injury.

This paper reviews the recently discovered role of sulfhydryls and early vascular injury in the pathogenesis of acute gastric mucosal injury. In the rat ethanol caused a dose-dependent decrease in nonprotein sulfhydryl concentration in the gastric mucosa within 1-5 min following an intragastric dose. These biochemical changes were accompanied by increased vascular permeability in the glandular stomach as revealed by the measurement of extravasated Evans blue injected i.v. prior to the administration of ethanol. Morphologic evidence of vascular injury was provided by labelling of damaged blood vessels in the stomach following the i.v. administration of colloidal particles in the form of india ink or monastral blue. The functional and structural damage to capillaries and venules in the glandular stomach was also maximal within 1-6 min after 1 ml of 75 or 100% ethanol given orally. Pretreatment with sulfhydryl (SH) containing drugs (e.g., L-cysteine, N-acetyl-L-cysteine, cysteamine, dimercaprol) or prostaglandin (PG) F2 beta prevented the ethanol-induced increase in vascular permeability, the labelling of blood vessels with vascular tracers, and the subsequent haemorrhagic erosions. The desquamation of superficial epithelial cells, however, was not markedly modified by either SH or PG compounds. This organoprotective effect of SH and PG drugs was virtually counteracted in adrenalectomized rats that exhibited "vascular fragility". Glucocorticoid treatment restored the response of adrenalectomized animals. Thus, a SH- and glucocorticoid-sensitive early vascular injury seems to be of major significance in the pathogenesis of haemorrhagic gastric erosions and SH-containing compounds represent a new group of cytoprotective or organoprotective agents.

Animals↗
PubMed1995

Clinical features and outcome of patients with thin and ultrathin glomerular membranes.

There is considerable disagreement regarding the natural history of renal disease associated with thin glomerular basement membranes (TGBM). We followed 43 patients (19 male), mean age 41.6 years (range 19-73) for a mean of 88 months (48-140). TGBM was recognized in adults when glomerular basement membrane thickness, measured from multiple sites in electronmicrographs of renal biopsy tissue as the harmonic mean, was < 320 nm. At presentation, 95% had microscopic haematuria, 12% macroscopic haematuria, 14% loin pain, 28% proteinuria, and 14% hypertension. There was no difference in GBM width between the sexes (male 258 nm vs. female 251 nm) but there was a significant negative correlation between age and GBM width (r = -0.53, p < 0.001), with older patients having the thinnest membranes. Twenty six patients had ultrathin GBM (< 270 nm), of whom 54% had 3+ haematuria vs. 12% of the group with BM > 270 nm (p < 0.01). In the ultrathin group, 71% had loss of anionic charge from the GBM, vs. 17% in those with membranes which were thin but > 270 nm (p < 0.05). Proteinuria occurred more frequently in those with GBM > 270 nm, 65% vs. 8% in the ultrathin group (p < 0.01). Thin GBM were associated with a benign prognosis, as after a mean follow-up of 85 months (48-140), there was no significant change in either serum creatinine or mean arterial blood pressure. Patients with ultrathin GBM had greater loss of GBM anionic charge, which might result in both an alteration of flow characteristics within the glomerular capillaries and also increased fragility of the glomerular basement membrane with likelihood of rupture and resultant macroscopic haematuria.

Adult↗
PubMed1995

Capillary electrophoresis of peptides using rectangular and cylindrical geometries: a comparative study.

A study on the use of rectangular columns in capillary zone electrophoresis (CZE) is presented. The equations controlling the hydrodynamic flow and the plate height in rectangular capillaries are deduced. Several experiments were carried out in order to test the validity of these equations. Also, the possibilities of these columns in terms of thermal dissipation, efficiency, analysis speed and sample capacity were studied and compared with those for cylindrical tubing. The results from both rectangular and cylindrical columns are compared to each other, employing the parameters mentioned above, and also with those predicted by theory. The advantages, i.e. better heat dissipation, higher speed and larger sample capacity, and drawbacks, i.e. high fragility and incompatibility with some capillary electrophoresis instruments, of employing rectangular geometries in CZE are discussed.

Electric Conductivity↗
PubMed1991

Studies of crystallization conditions for native and subtilisin-cleaved pig brain tubulin.

A survey of crystallization conditions for pig brain tubulin, using standard vapor diffusion techniques in sitting drops or capillaries, has resulted in irregular, fragile needles or plates with a largest dimension of 0.5 mm. These occurred in 2.5% PEG (MW 3350), 0.1 M Pipes, pH 6.2 and 6.4, 2-16 mM MgSO4, 10-15 mM DTE, and 0.1 mM GDP at 8 degrees C. When GTP replaced GDP these aggregates did not form under any of the conditions surveyed (temperature: 8-10 degrees C; MgSO4: 2-16 mM; pH 6-7; PEG, MW 3350: 1.25-12.5%). EM observations demonstrated that sheets of rings appear in crystal solutions in the presence of GDP or GTP. These results are consistent with the results of Howard and Timasheff (1986, Biochemistry 25, 8292-8300) that tubulin rings form in the presence of GDP or GTP but more readily in GDP. Tubulin crystallization experiments are hampered by tubulin's high degree of heterogeneity. Much of the variability lies in the carboxyl terminal region. Conditions for limited digestion of the heterodimer by subtilisin, removing only the carboxyl terminus, were determined. Reduction of heterogeneity was demonstrated by isoelectric focusing. The solubilities of native and subtilisin-cleaved tubulin in MgSO4, (NH4)2SO4, PEG (MW 1450, 3350, 10,000), DMSO, and MPD were compared. Subtilisin-cleaved tubulin precipitated more readily than native tubulin under all conditions surveyed, consistent with the removal of the highly acidic carboxyl terminus. Vapor diffusion experiments using subtilisin-cleaved tubulin under conditions where native tubulin forms needles or plates resulted in similar aggregates.

Animals↗
PubMed2005

Microcirculation disturbance affects rats with acute severe pancreatitis following lung injury.

AIM: To study the effects of microcirculation disturbance (MD) on rats with acute severe pancreatitis (ASP). METHODS: We developed ASP rat models, and anatomized separately after 1, 3, 5, 7, and 9 h. We took out blood and did hemorrheologic examination and erythrocyte osmotic fragility test, checked up the water content, capillary permeability, and genetic expression of intercellular adhesion molecule-1 (ICAM-1) in lung tissues, examined the apoptosis degree of blood vessel endothelium while we tested related gene expression of Bax and Bcl-2 in lung tissues. We did the same examination in control group. RESULTS: The viscosity of total blood and plasma, the hematocrit, and the erythrocyte osmotic fragility were all increased. Fibrinogen was decreased. The water content in lung tissues and capillary permeability were increased. Apoptosis degree of blood vessel endothelium was increased too. ICAM-1 genetic expression moved up after 1 h and reached its peak value after 9 h. CONCLUSION: MD plays an important role in ASP following acute lung injury (ALI). The functional damage of blood vessel endothelium, the apoptosis of capillary vessel endothelium, WBC edging-concentration and the increasing of erythrocyte fragility are the main reasons of ALI.

Acute Disease↗
PubMed1975

Retinal capillary junctions: ultrastructural tight junction artefacts induced by sodium ions and membrane reduction in streptozotocin diabetes.

Retinal capillary junctions were analysed in normal and diabetic rats and in a human retina with the electron microscope. Diabetes mellitus was induced with streptozotocin. The retinae were fixed in Palade's osmium tetroxide containing sodium or calcium ions and block-stained in uranyl acetate. With Ca-fixation, no significant difference in interendothelial cleft width was detected between retinal layers or between normal and diabetic retinae. Diabetes caused a narrowing of the clefts in the Na-fixed tissue X +/- SE, n=375; Normal: 78.6 +/- 300 A; Diabetic: 57.7 +/- 2.42 A; p less than 0.001). A significant correlation was found between cleft width and the length of the tight junctions or zonulae occludentes (p less than 0.001). In the nerve fibre layer of the Na-diabetic retina, where cleft narrowing was greatest, there was an increase in length of the zonulae occludentes from 22.8 +/- 2.2% to 41.6 +/- 3.7% (p less than 0.001). Ca-fixation prevented these changes, indicating that at least some zonulae occludentes were interendothelial extraction artefacts. In the normal retina, endothelial cell membrane thickness was greater with Ca- than Na-fixation (p less than 0.001). Diabetes caused a decrease in membrane thickness of Ca-fixed tissue (p less than 0.001). The diabetic decrease in membrane thickness may explain the increased fragility and increased permeability of diabetic capillaries. Calcium binding by endothelial cell membranes is of primary importance in anticoagulation which is defective in diabetes.

Animals↗
PubMed1975

Ultrastructural changes of endothelium associated with thrombocytopenia.

In a study of the relationship between thrombocytopenia and increased vascular fragility, changes in the endothelium of capillaries and postcapillary venules of the tongue were examined by electron microscopy. Adult male albino rabbits (4 kg) were maintained thrombocytopenic (platelets less than 20,000/cu mm) up to 24 hr by one to three injections of guinea pig antirabbit platelet serum. Within 6 hr the normal projections and folds of the lumenal surface of the endothelial surface were largely effaced. In addition, the endothelium became thinner. In places, pores and membranous diaphragms were observed. Endothelial junctions appeared normal. Identical findings were observed if rabbits were made thrombocytopenic by administration of intraperitoneal busulfan. Intravenously administered Thorotrast was observed in endothelial cells and in the extravascular spaces within 3 min after injection into thrombocytopenic animals, while it was seen only intravascularly in control rabbits. With the spontaneous restoration of circulating platelets, the endothelium reverted to normal.

Animals↗
PubMed2006

Simplified molecular diagnosis of fragile X syndrome by fluorescent methylation-specific PCR and GeneScan analysis.

BACKGROUND: Fragile X syndrome (FXS), the most common cause of inherited mental impairment, is most commonly related to hyperexpansion and hypermethylation of a polymorphic CGG trinucleotide repeat in the 5' untranslated region of the FMR1 gene. Southern blot analysis is the most commonly used method for molecular diagnosis of FXS. We describe a simplified strategy based on fluorescent methylation-specific PCR (ms-PCR) and GeneScan analysis for molecular diagnosis of fragile X syndrome. METHODS: We used sodium bisulfite treatment to selectively modify genomic DNA from fragile X and normal lymphoblastoid cell lines and from patients. We then performed ms-PCR amplification using fluorescently-labeled primers complementary to modified methylated or unmethylated DNA. Amplification products were resolved by capillary electrophoresis. FMR1 mutational status was determined by a combination of fluorescent peak sizes and patterns on the GeneScan electropherogram. RESULTS: DNA samples from male and female persons with known NL, PM, and FM FMR1 CGG repeats were analyzed. Each FMR1 genotype produced a unique GeneScan electropherogram pattern, thus providing a way to identify the various disease states. The number of CGG repeats in all NL and PM alleles were determined accurately. Analysis by both the new assay and Southern blot of a family segregating with FXS showed complete concordance between both methods. CONCLUSIONS: This simplified molecular diagnostic test, based on fluorescent methylation-specific PCR, may be a suitable alternative or complement to Southern blot analysis for the diagnosis of FXS.

DNA Methylation↗