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At least 1,729 records · Page 96Linked to original sources
PubMed2005

Regional and developmental variations of blood vessel morphometry in the chick embryo chorioallantoic membrane.

Avian eggs contain all the necessary materials for embryonic development except for oxygen, which diffuses in from the environment via pores in the hard, calcified eggshell to the chorioallantoic membrane (CAM), the respiratory organ, which is rich in blood vessels. An air cell is formed at the blunt pole of the egg between the two membranes of the eggshell and enlarges during incubation due to water vapor loss. In this study of the CAM of chicken eggs, we compared blood vessel numerical density [N(A(v))], area fraction of blood vessels [A(A(v))], CAM thickness (D(CAM)), total length of blood vessels (L) and surface area of the CAM attached to the eggshell (CAMre) with those under the air cell (CAMac) during incubation. We found that N(A(v)), A(A(v)), D(CAM) and L of the CAM increase with embryonic age and development. The N(A(v)), A(A(v)) and L under the air cell were higher in relation to the rest of the CAM at all ages tested, while the D(CAM) under the air cell was always lower than around the rest of the egg. Since the eggshell over the air cell has a relatively greater porosity, and the respiratory gas exchange ratio there is higher than at other areas of the egg, there is a correlation between all the above morphometric data and the eggshell porosity. This suggests optimization of embryonic gas exchange in the chicken egg. We would like to propose that, during natural incubation, an increased gas diffusion under the air cell, together with increased blood vessel numerical density, may compensate for covering of the central part of the eggshell by the incubating parent.

Age Factors↗
PubMed2003

Expression of somatostatin receptor subtypes 1 to 5 in tumor tissue and intratumoral vessels in malignant endocrine pancreatic tumors.

Somatostatin analogs are well established in the treatment of malignant endocrine pancreatic tumors (EPTs). Our goal is to individualize their treatment using receptor-subtype-specific analogs and, therefore, exploring the receptor expression is highly important. We have examined the expression of somatostatin receptor (sst) subtypes 1-5 on tumor cells and in intratumoral vessels in 28 tumor tissues from malignant EPTs with immunohistochemistry using sst-subtype-specific polyclonal antibodies. We found that sst(2) and sst(4) stained positive in 90% and sst(1) in 70% of the tumor tissues, whereas sst(3) and sst(5) stained positive in only 50% of the tumor tissues. Sst expression in intratumoral vessels was high for sst(2) and sst(4) (80%), moderate for sst(1) (40%), and low for sst(3) and sst(5) (10%). The ssts were evenly distributed among the different tumor subtypes. However, tumors belonging to the same subgroup of EPTs showed a variable expression of receptor subtypes. No differences in receptor-subtype expression could be seen between poorly and welldifferentiated tumors, nor between primary tumors and metastases. Prior medical treatment did not influence sst expression pattern. In conclusion, sst(2) and sst(4) were expressed in most tumor tissues and intratumoral vessels from EPTs. However, sst(3) and sst(5) were lacking in half of the tumor tissues and in most of the intratumoral vessels. These differences indicate the importance of determining each tumor s subset of receptors before treatment with receptor-subtype-specific analogs is initiated. The importance of sst expression in intratumoral vessels is not yet known.

Adult↗
PubMed1997

[An experimental study on the use of the Hilbert operator as a method of signal preprocessing for the determination of oxygen saturation in retinal vessels].

For the non-invasive measurement of the oxygen saturation in human retinal vessels, the light reflected by a vessel and its surroundings is evaluated. Differences in the absorption and scattering properties of the optical media provide so-called vessel profiles, but the central vessel section is often disturbed by a regular reflex. In order to eliminate this reflex, a method based on the Hilbert transform is presented, which can be used for the determination of logarithmic differences between the reflected light on and that beside the vessel. The data for our investigations were produced by simulation of the radiation transport in multi-layered tissue. A linear regression between expected and measured values based on 40 pairs was used for the evaluation of the proposed method. A linear relationship was shown to exist.

Anisotropy↗
PubMed1986

The effect of maternal smoke exposure on the ultrastructure of fetal peripheral blood vessels in the mouse.

Ultrastructural changes have been found in umbilical blood vessels, placental blood vessels, and peripheral blood vessels of human fetuses whose mothers smoked during pregnancy. This study was undertaken to determine if similar changes could be found in peripheral blood vessels of mice fetuses whose mothers were exposed to cigarette smoke during pregnancy. Breeding mice of the C57BL/KsJ strain were placed in a smoking box similar to that described by Younoszai and exposed to cigarette smoke intermittently. This produces carbon monoxide levels in the adult mice similar to that found in human adults smoking one pack of cigarettes per day. Similarly caged mice of the same strain were used as controls. The female mice were not removed from their cage from pre-conception time until after delivery. Upon delivery each pup was sacrificed via neck fracture and the entire pup was immersed in a solution of 2.5% glutaraldehyde in 0.1 M cacodylate buffer at pH 7.3. While still under solution, the rear leg muscles were dissected free, sliced, and immersed in the same preservative for four to five hours. They were then placed in fresh 2.5% glutaraldehyde mixture overnight. The tissues were post-fixed in osmium ferrocyanide and en-block stained with uranyl acetate in a graded series of alcohol. The tissues were infiltrated with and embedded in Spurr. Sections were taken via an ultramicrotome and post-stained with uranyl acetate and lead citrate. The sections were examined in a Philips 201 electron microscope at 60 KV. In the peripheral vessels of the fetuses from smoke-exposed mothers, endothelial blebbing (both surface-type and vacuole-type) was seen.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1998

Directional coronary atherectomy versus coronary angioplasty in vessels larger than 3 mm in diameter.

It has been proposed that directional coronary atherectomy (DCA) should be an intervention of choice in larger vessels as one can achieve a greater minimal luminal diameter with DCA than with percutaneous transluminal coronary angioplasty (PTCA). This in turn should translate into a higher success rate and may even reduce the restenosis rate. The aim of this study was to compare DCA versus PTCA in vessels > 3 mm in diameter. One hundred fifty consecutive patients who met the inclusion criteria and had DCA were compared to 150 similarly selected PTCA patients. PTCA patients were selected from the era immediately preceding the advent of DCA so that selections bias could be excluded. All patients with ostial lesions, restenosis, vessels < 3 mm in diameter, and vessels with more than two significant lesions were excluded. Distal segments and circumflex cases were excluded as they formed a small subsegment. Both groups were similar in terms of demographic, clinical and angiographic variables. Quantitative analysis showed that the initial net gain was significantly greater in the DCA group than in the PTCA group (2.36 +/- 0.8 mm vs. 1.78 +/- 0.7 mm; p < 0.05). Residual stenosis was 11% with DCA compared to 33% with PTCA (p < 0.05). Despite these improved anatomical results the procedural success rates were similar (91.5% vs 84%). Major in hospital complications (death, acute occlusion, MI, emergency CABG, re-do) were higher in the DCA group than in the PTCA group (12% vs 6%). Clinical follow-up on 276 patients (150 DCA vs 126 PTCA) showed a 6 month clinical restenosis rate of 18% vs 28%, respectively. The incidence of re-do in 24 hours for acute occlusion was 6% for DCA and 1% for PTCA. In large-sized vessels DCA results in a lower restenosis rate. However, despite a lower incidence of residual stenosis, the complication rate tends to be higher with DCA (p < 0.05).

Aged↗
PubMed2003

Origins and pathways of fluid entering sublobular lymphatic vessels in cat livers.

The liver, which produces a large volume of lymph, has a lymphatic system which can be classified into three categories: portal, sublobular, and superficial lymphatic vessels. As little is known about the origin and pathways of sublobular lymph, this study demonstrates pathways of interstitial fluid flowing into sublobular lymphatic vessels. Livers from cats whose thoracic ducts were either ligated or non-ligated were examined by light-, transmission electron- and scanning electron-microscopy (SEM). Complete ligation of the thoracic duct caused significant dilation of the hepatic sinusoids, the space of Disse, and channels passing through the limiting plate. Sublobular interstitial space and sublobular lymphatic vessels were also expanded. The channels between hepatocytes forming the limiting plate contained collagen fibers, and connected the space of Disse with a sublobular interstitial space. The alkali-water maceration/SEM confirmed that collagen fibers traversing the layer of the limiting plate independently of blood vessels connected collagen fibers in the space of Disse with those in the sublobular space. Complete ligation of the thoracic duct also showed an accumulation of mast cells and plasma cells in the sublobular interstitial space. Our data suggest that fluid in the space of Disse flows along collagen fibers in channels traversing the limiting plate as well as those along the sinusoids and central veins that drain into sublobular veins, and enters the sublobular interstitial space to finally lead into sublobular lymphatic vessels. Our study has also shown that hepatic lymphostasis causes the accumulation of mast cells and plasma cells in the sublobular interstitial space, which may be involved in lymphangiogenesis and fibrogenesis.

Animals↗
PubMed2004

Steroid receptors in blood vessels of the rhesus macaque endometrium: a review.

Estradiol (E) and progesterone (P) act on the primate endometrium to induce dramatic changes in the vascular system during the menstrual cycle. These changes include vessel breakdown and bleeding during menses, heightened angiogenesis during the early proliferative phase, and extensive growth of the spiral arteries in the luteal phase of the cycle. Because steroid hormone action is dependent upon the presence of specific nuclear receptors in target tissues, we used immunocytochemistry with receptor-specific monoclonal antibodies to characterize the spatial and temporal expression of estrogen receptor alpha (ERalpha), estrogen receptor beta (ERbeta), progesterone receptor PR and androgen (A) receptor (AR) in the endometrial vessels of rhesus macaques (Macaca mulatta). The only sex steroid receptor that was present in the endothelium and smooth muscle walls of endometrial vessels was ERbeta. ERalpha, PR, and AR were not detectable in either the endothelium or vascular smooth muscle cells of primate endometrial vessels. However, all of these receptors were strongly expressed by the perivascular stroma, and in these cells, all were modulated by the changes in levels of E and P during the cycle. We concluded that any direct effects of E on endometrial vessels would be mediated by ERbeta, and that the actions of P and A, and possibly some of E, were indirectly mediated through perivascular stromal cells.

Animals↗
PubMed2006

Imaging of lymphatic vessels in breast cancer-related lymphedema: intradermal versus subcutaneous injection of 99mTc-immunoglobulin.

OBJECTIVE: The disordered physiology that results from axillary lymph node clearance surgery for breast cancer and that leads to breast cancer-related lymphedema is poorly understood. Rerouting of lymph around the axilla or through new pathways in the axilla may protect women from breast cancer-related lymphedema. The aim of the study was to compare intradermal with subcutaneous injection of technetium-99m ((99m)Tc)-labeled human polyclonal IgG (HIG) with respect to lymphatic vessel imaging. MATERIALS AND METHODS: Six women with breast cancer-related lymphedema underwent unilateral upper limb lymphoscintigraphy, using a web space injection of (99m)Tc-labeled HIG, after intradermal and subcutaneous injections on separate occasions. Multiple sequential images were obtained of the affected upper limb and torso over 3 hr on each occasion. Accumulation of activity in blood was quantified from venous blood samples taken from the opposite arm. RESULTS: Imaging after intradermal injection clearly showed discrete lymphatic vessels in five of six patients, in contrast to imaging after subcutaneous injection, which did not show any discrete vessels in any patient. Intradermal injection resulted in more rapid visualization of cutaneous lymph rerouting than subcutaneous injection in six of six patients. Recovery of injected (99m)Tc-labeled HIG in venous blood was greater after intradermal injection in six of six patients. CONCLUSION: In patients with breast cancer-related lymphedema, lymphatic vessels are more clearly depicted after intradermal than subcutaneous injection as a result of direct access of radiotracer to dermal lymphatics. This finding has implications for imaging lymphatic vessel regeneration and lymph rerouting.

Adult↗
PubMed1994

The blood vessels in Reissner's membrane of the rat.

Blood vessels on Reissner's membrane were electron-microscopically found in 24 out of 30 rats of the Wistar strain. The vessels were noted in the upper turns, mainly in the third turn of the cochlea. They originated from radiating arterioles in the upper spiral ligament and took straight courses radially down to the spiral limbus, and further to the modiolus, running along the surface of the scala vestibuli side of the membrane. Their diameter was approximately 4 microns. Bifurcated blood vessels were occasionally detected in 3 out of the 24 rats that possessed the vessels in the membrane. From the morphological point of view the blood vessels in Reissner's membrane may possibly have some function in the inner ear of the rat.

Animals↗
PubMed1996

The accurate assessment of changes in retinal vessel diameter using multiple frame electrocardiograph synchronised fundus photography.

PURPOSE: Detection and precise quantification of changes in retinal vessel diameter by image analysis techniques is important in a number of fields of research. The retinal vessels have been shown to exhibit pulse related changes in diameter. These may need to be taken into account when studying diameter changes due to other causes. This study examined the effect of using multiple fundus photographs with and without electrocardiographic synchronisation on the size and statistical significance of changes in mean retinal vessel diameter. METHODS: Twelve fundus photographs spaced throughout the cardiac cycle by electrocardiographic synchronisation were taken in 10 normal volunteers: (a) at rest, (b) during isometric exercise, and (c) during oxygen inhalation. Vessel diameters were measured using a computer assisted image analysis system. Subsequently smaller sample sizes, with and without electrocardiograph synchronisation were modeled from the available data. RESULTS: With a group of ten subjects six or more electrocardiograph synchronised photographs enable reliable detection of small diameter changes (1.4%) induced by isometric exercises while other methods either failed to detect change or were unreliable at doing so. With six subjects twelve synchronised photographs were required to reliably detect a change of the same magnitude. Larger diameter changes (5.4%) were detected by any method including a single unsynchronised photograph. CONCLUSIONS: Multiple frame electrocardiograph synchronized fundus photography permits more accurate detection of small changes in retinal vessel diameter.

Adult↗
PubMedDate not supplied

Lateral deformation and movement effects on flow through distensible tube models of blood vessels.

The fluid flow through a tube with an oscillating elliptical cross-section was analyzed in order to understand better the effects of lateral deformation and movement on flow patterns in large and medium-sized blood vessels. Time-dependent elliptical deformation may be caused by external forces, as is the case for the large vessels near the heart, or by lateral movement of the entire compliant vessel, as in the coronary arteries. An analytic, perturbation-type solution was found for the case of fully developed flow in a tube where the cross-section oscillated periodically from an ellipse to a circle. Analytic expressions were found for all three components of the velocity vector. The effects of the deformation on the axial velocity profile included near-wall fluctuations in velocity that depended on the local wall motion. At higher values of the Womersley parameter, these effects were more pronounced. Secondary flow patterns were established that swirled fluid from the center of the vessel to the walls, then back to the center. It was concluded that these phenomena could be important to flow in the largest vessels, but may not be so important in determining flow patterns in the coronary arteries.

Blood Flow Velocity↗
PubMedDate not supplied

The predictive value of posterior pole vessels in retinopathy of prematurity.

Dilation and tortuosity of the posterior pole vessels "(plus disease)" is a sign of poor prognosis and may be associated with threshold or prethreshold retinopathy of prematurity (ROP). We have found that normal posterior pole vessels are a reliable marker for the absence of stage 3 ROP. One hundred thirty-two consecutive premature infants weighing less than 1600 g at birth underwent ROP examinations between 32 and 40 weeks' postconceptional age. The status of the posterior pole vessels was compared to peripheral retinal pathology. Vascular findings in the posterior pole were graded 0, 1, 2, or 3, with 0 representing normal arterioles and venules and 3 representing plus disease. The remainder of the fundus examination was recorded using the international Classification of ROP, then converted to a severity scale based on zone and stage of ROP. For each infant, only one examination representing the most severe stage of ROP reached prior to treatment or spontaneous regression was used for data analysis. There was a highly significant Spearman's rank correlation (rs = 0.65) between the posterior pole vascular abnormalities and the severity of ROP in the retinal periphery. Clinically important ROP was not found in any patient with normal posterior pole vessels (grade 0) and stage 3 disease was usually associated with both venous and arterial vascular abnormalities (grades 2 or 3). When ocular examination of premature infants is difficult because of poor dilation of the pupil, hazy media, or medical instability, normal appearance of the posterior pole vessels can be a reassuring finding if it is necessary to postpone complete fundus examination in infants at risk for ROP.

Fundus Oculi↗
PubMed2006

The analysis and diagnosis of unstable behavior of the blood vessel wall with an aneurysm based on noise science.

Previously, one of the authors developed a noninvasive measurement method of acceleration and deceleration during the expansion process of the blood vessel wall under pulsatile pressure flow by measuring the strain rate of the blood vessel wall using a supersonic Doppler effect sensor aided by computer analysis (DPC method). In this paper, on the basis of the analysis of chaos theory, that is, the complexity of science, the unstable behavior of the blood vessel wall with an aneurysm was investigated by identifying the characteristic DPC wave forms induced by the onset and progression of aneurysm. These results showed that unstable dynamic behavior of the blood vessel wall occurs due to the progression of the aneurysm. Furthermore, using the theoretical analysis of chaos, this unstable behavior of the blood vessel wall was quantified and the fundamental principle of a noninvasive diagnostic method of the progressive degree of aneurysm was proposed.

Aneurysm↗
PubMed1976

[Vital microscopic investigation of terminal blood vessels in patients with diabetes mellitus].

It is reported on findings of vital-microscopic investigations at the terminal vascular system of the conjunctiva bulbi and the mucous membrane of the lips carried out on 50 juvenile diabetics and 50 test persons of the same age. By quantitative establishment of the morphological and functional changes of the vessels and the aggregation of the erythrocytes in the different regions of the terminal vascular system we succeeded in delimitating all 50 diabetes as individuum or as collective (x equals 10.7 +/- 1.5) from the test persons (x equals 3.4 +/- 0.9) by means of a point system (p less than 0.001). In 4 figures typical vascular findings are demonstrated. No pathognomonic significance was ascribed to the individual vascular findings. The morphological and functional changes of the vascular wall are regarded as an expression of fundamental reactive possibilities of the vessels of the terminal vascular system after influence of different factors of risk. As criteria of the findings were used: venular sacculations, meander-like forms, convolutions, haemorrhages, aneurysms, reticular structures, varieties of calibres, changed arteriolarvenular relations of the inner diameter of the vessels, constant proof of aggregates of erythrocytes with temporary standstill of the flow in the different parts of the terminal vascular system. The author is of the opinion that with simultanuous establishment of the morphological and functional changes of wall of the vessel and content of the vessel degenerative changes in diabetes mellitus are provable earlier than at the eye-ground by means of ophthalmocoscopy when only morphological findings are established. The reciprocities between the vascular changes and the rheological properties of the blood are described.

Adult↗
PubMed1999

Correlation of VEGF expression by leukocytes with the growth and regression of blood vessels in the rat cornea.

PURPOSE: To determine the temporal and spatial relationships between neovascularization and basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF) mRNA and protein expression in the rat cornea after cautery with silver nitrate. METHODS: In female Sprague-Dawley rats, a silver nitrate applicator was placed on the central cornea to elicit circumferential angiogenesis, and blood vessel growth was quantified by digital image analysis of corneal flat-mounts. Total RNA or protein was extracted from whole corneas until 1 week after cautery, and bFGF and VEGF mRNA and protein levels were determined by reverse transcription-polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA). To localize VEGF mRNA and protein, paraformaldehyde-fixed and paraffin-embedded histologic cross sections of corneas were examined by in situ hybridization and immunohistochemistry. Macrophages were identified by ED2 immunohistochemistry. To examine the regulation of VEGF, rats were treated with dexamethasone (0.5 mg/kg per day) and hyperoxia (70% O2). RESULTS: The neovascular response progresses in three phases: (1) a nonproliferative phase preceding vessel growth (< or = 48 hours after cautery); (2) a proliferative phase with maximal growth rate between 3 and 4 days; and (3) a regressive phase (day 7) with a decrease in vessel density accompanying the completion of vessel elongation. In corneas after cautery, bFGF mRNA expression was unchanged, and bFGF protein concentration decreaseed by 97% after 24 hours and returned to control levels by day 7. In contrast, VEGF164 and VEGF188 mRNA splice variants and protein peaked 48 hours after cautery, remained elevated 4 days after cautery, and decreased to near baseline by day 7. The peak concentration of VEGF in the cornea at 48 hours was calculated to be 720 pM, which is sufficient to evoke a functional response. In situ hybridization and immunohistochemistry showed VEGF expressed initially in neutrophils (24 - 48 hours) and subsequently in macrophages (4 days) adjacent to the cautery site. Treatment with either dexamethasone or systemic hyperoxia inhibited both neovascularization and the increase in VEGF expression. Dexamethasone inhibited 27% of cautery-induced VEGF upregulation at 24 hours and 23% at 48 hours, hyperoxia inhibited 32% at 24 hours and 43% at 48 hours, and combined treatment with both dexamethasone and hyperoxia had an additive effect (56% inhibition at 24 hours). CONCLUSIONS: VEGF production by leukocytes correlates temporally and spatially with cautery-induced angiogenesis in the rat cornea. Both inflammatory products and hypoxia appear to sufficiently increase VEGF expression near the cautery lesion to increase vascular permeability of limbal vessels and induce endothelial cell migration and proliferation.

Animals↗
PubMed1999

Ultrastructural features of immaturity in blood vessels of neonatal rat spinal cord.

Ultrastructural study was carried out on the lumbo-sacral segment of the spinal cord in 1, 3, 6, 9, 12, 15, 18, 21 and 25-day-old rats. Unusual features of blood vessels in postnatal life of rats were observed: capillaries with abundant endothelial cells, numerous invaginations and narrow lumen. In addition, microvilli of diverse size and number on the luminal surface of capillaries as well as larger vessels were present. They were more numerous in younger animals. An intriguing finding, not observed in older animals, was the appearance of abluminal protrusions projecting into surrounding tissue. Closed endothelial junctions were noted in all the investigated vessels. The above mentioned ultrastructural features indicate an immature character of blood vessels. The presence of this kind of vessels during the postnatal period may be connected with vascularisation of spinal cord due to the myelination process.

Age Factors↗
PubMed2000

Influence of vessel size on early and late outcomes after primary angioplasty for acute myocardial infarction.

Small vessel size is associated with worse outcomes after elective angioplasty, but the effect of vessel size on outcomes after primary angioplasty for acute myocardial infarction has not been studied. We evaluated outcomes in 1,490 consecutive patients treated with primary angioplasty comparing patients with small (< 3.0 mm) versus large ( 3.0 mm) vessels. Outcomes were worse in patients with small vessels with lower procedural success rates (92% versus 96%; p = 0. 002), higher rates of reinfarction (5.5% vs. 3.4%; p = 0.07), more late reocclusion (12.5% vs. 4.1%; p = 0.002), less improvement in ejection fraction (1.8% vs. 4.2%; p = 0.04), lower follow-up ejection fraction (53.7% vs. 56.5%; p = 0.03), and higher 30-day and late mortality (12.5% vs. 6.4%; p = 0.0002). The higher mortality can be explained by a higher baseline risk profile combined with worse procedural results and higher rates of reocclusion and reinfarction. These data stress the importance of developing new strategies to improve procedural and late outcomes after primary angioplasty in patients with small vessels.

Adult↗
PubMed1998

Angiogenesis of extra- and intraembryonic blood vessels is associated with expression of nestin in endothelial cells.

For a long time, intermediate filament protein nestin was recognized as a specific constituent of the cytoskeleton of developing neural cells and skeletal muscle. Recent reports by other investigators demonstrated that nestin may also be expressed in other cell types. Here we give evidence that nestin is expressed by endothelial cells of developing blood vessels in the rat. Using anti-Rat-401 monoclonal antibody we identified high levels of nestin in the endothelium lining all blood vessels of E14-15 rat foetuses. Immunoreactivity for nestin was detected in both extraembryonic (chorion, placenta, umbilical cord) and intraembryonic blood vessels. In the body of the foetus, we observed nestin-positive endothelial cells in vessels located in the areas of the mesenchyme as well as in vessels supplying the developing organs (central nervous system, liver, lung, spleen, heart, digestive tube). The strongest positive signal was given by the endothelium of newly vascularized tissues. In contrast to the developing tissues, expression of nestin by vascular endothelial cells was greatly reduced in adult tissues.

Animals↗