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At least 649 records · Page 36Linked to original sources

PubMed2006

The pattern of renal vessels in live related potential donors pool. A multislice computed tomography angiography review.

OBJECTIVE: To assess the renal vessel anatomy, compare the findings with the perioperative findings, to determine the sensitivity of multislice computed tomography (CT) angiography in the work-up of live potential donors and to discuss and compare the results of the present study with the reported results using single slice CT, magnetic resonance (MRI) and conventional angiography (CA). METHODS: Retrospective analysis of the angiographic data of 118 of prospective live related kidney donors was carried out from October 2004 to August 2005 at the National Organ Transplant Centre, Tripoli Central Hospital, Libya. All donors underwent renal angiography on multislice (16-slice) CT scan using 80 cc intravenous contrast with 1.25 mm slice thickness followed by maximum intensity projection (MIP) and volume rendering techniques (VRT) post-processing algorithms. The number of vessels, vessel bifurcation, vessel morphology and venous anatomy were analyzed and the findings were compared with the surgical findings. RESULTS: Multislice spiral CT angiography (MSCTA) showed clear delineation of the main renal arteries in all donors with detailed vessel morphology. The study revealed 100% sensitivity in detection of accessory renal vessels, with an overall incidence of 26.7%, which is the most common distribution in the parahilar region. CONCLUSION: The present study showed 100% sensitivity in the visualization and detection of main and accessory renal vessels. These results were comparable with conventional angiography which has so far been considered as the gold standard and were found superior in specificity and accuracy to the use of single slice CT (SSCT) and MR in the angiographic work-up of live renal donors. Due to improved detection of accessory vessels less than 2 mm in diameter, a higher incidence of aberrant vessels was seen on the right side as has been suggested so far.

Adult↗

PubMed1990

Blood vessel invasion in gastric carcinoma.

In an effort to identify factors in primary tumors that would predict liver metastases, we retrospectively reviewed 102 patients with gastric cancer, and their tissue blocks were restained. New staining methods for elastin and endothelium were used to identify intratumoral vessels. Blood vessel invasion, thus detected, was analyzed quantitatively, as well as qualitatively, according to the location of invasion, the size of the involved vessel, and the mode of invasion. The invasion was then compared with the presence of liver metastasis by the chi 2 test, the Mann-Whitney U test, and the Student t test. Discrimination analysis of factors significantly correlated with liver metastasis was performed with linear discrimination function to identify a predictive model for liver metastasis. Significant differences in qualitative frequency of blood vessel invasion (p less than 0.01), the number of lymph node metastases (p less than 0.05), and the depth of tumor invasion (p less than 0.05) were found in those patients in whom liver metastasis developed, as compared with 5-year disease-free survivors. Quantitative analysis of blood vessel invasion revealed eight other factors correlated with liver metastasis; frequency of blood vessel invasion in the 0.01 to 0.1 mm and 0.1 to 1 mm diameter vessels, in the forms of complete, partial tumor thrombi, and vessel wall invasion, in the submucosa and the subserosa, and the number of anatomic stomach layers involved. Application of the discrimination coefficient to these factors allows prediction of liver metastasis with 81.8% sensitivity, 85.3% specificity, and 83.6% accuracy. Liver metastasis can be predicted from the qualitative and quantitative examination of blood vessel invasion within the primary tumor by the use of an elastic fiber stain.

Capillaries↗

PubMedDate not supplied

Self-expanding versus balloon-mounted stents for vessel recanalization following embolic occlusion in the canine model: technical feasibility study.

BACKGROUND AND PURPOSE: Despite advances in mechanical thrombolysis for acute stroke, recanalization rates remain approximately 50%-60%. Technologic improvements allowed safe intracranial delivery of stents. To study the feasibility of stent-assisted recanalization for acute stroke, we deployed self-expanding or balloon-mounted stents in 2- to 3.5-mm canine vessels acutely occluded with clot emboli. METHODS: Six mongrel dogs were placed under general anesthesia. A guiding catheter was placed in the distal vertebral artery or an external carotid artery branch. A 7 x 3 mm (length x diameter) soft or hard clot was injected into the catheter and allowed to embolize distally; 20 vessels were successfully occluded. After systemic heparin anticoagulation, recanalization with a self-expanding stent was attempted in 11 vessels (5 occluded with soft clot; 6, with hard clot). Balloon-mounted stents were placed in an attempt to revascularize 9 vessels (4 occluded with soft clot; 5, with hard clot). Vessel recanalization was assessed as the primary end point. Side-branch occlusion and stent-induced vasospasm were also assessed. RESULTS: Thrombolysis in Myocardial Infarction/Thrombolysis in Cerebral Infarction flow for 11 vessels treated with self-expanding stents versus 9 treated with balloon-mounted stents was as follows: grade 3, 91% of vessels versus 78% of vessels; grade 2, 0% versus 11%; grade 1, 9% versus 0%; grade 0, 0% versus 11%. Lower rates of spasm and side-branch occlusion were noticed with self-expanding stents. Grade 2/3 flow was achieved in 18/20 vessels (90%). CONCLUSIONS: Excellent recanalization was demonstrated with both stents. Recanalization in self-expanding stents was achieved without pre- or post-balloon dilation. Stents may prove to be a useful adjunct for intra-arterial acute stroke treatment.

Animals↗

PubMed1977

[Blood vessel coagulation with the argon laser].

Experimental studies on small blood vessels of the rat mesentery were performed in order to optimize current clinical argon laser coagulation technique of ocular neovascularization. The vessel effects were observed by means of vital microscopy and histological studies were done on coagulated vessels. Furthermore systematic variation of the coagulation parameters was done. The main results were as follows: Graded effects such as reversible vasoconstriction, endovascular thrombosis and complete separation of the vessel wall could be achieved with the argon laser on small vessels in surroundings of relatively low absorption. Short duration vessel closure resulted from endovascular thrombosis alone or in conjunction with downstream vasoconstrictions. Destroyed erythrocytes adhering to the vessel wall played a major role in endovascular thrombosis. Subendothelial structures were of minor importance. Longer lasting vessel closure could be achieved by summation of the effects of single exposures. Low risk vessel coagulation is only possible at exposure times of less than 20 msec. Currently available clinical argon lasers do not deliver the high laser powers needed for this purpose.

Animals↗

PubMed1982

Studies on the pathogenesis of avian rickets II. Necrosis of perforating epiphyseal vessels during recovery from rickets in chicks caused by vitamin D3 deficiency.

This study involved comparison of the distribution and integrity of perforating epiphyseal and marrow vessels with the stage of development and integrity of chondrocytes and the distribution of insoluble calcium in the proximal tibial growth plate of 3-week-old vitamin-D3-deficient hypocalcemic chicks and 3-week-old D3-deficient chicks 12, 36, 72, and 120 hours after an oral dose of 10,000 units vitamin D3. The aim was to clarify the mechanisms responsible for chondrocyte hypertrophy and cartilage calcification in the avian growth plate. Within 12 hours after administration of vitamin D3, serum calcium levels rose to normocalcemic levels. The following morphologic changes were first recognizable at the times indicated. Distal portions of previously elongated perforating epiphyseal vessels and adjacent proliferative and maturing chondrocytes underwent necrosis by 12 hours. Chondrocyte necrosis was not preceded by hypertrophy. By 36 hours, vascular and chondrocyte necrosis involved large portions of the thickened proliferating and maturing zone, and perforating epiphyseal vessels were shortened to a normal length. By 72 hours, chondrocyte hypertrophy and calcification resumed around the shortened epiphyseal vessels. By 120 hours, marrow had removed the necrotic cartilage, and morphologically normal growth plate was restored, with perforating epiphyseal and marrow vessels, both ending in a narrow hypertropic cartilage zone. The results indicate that proximity of chondrocytes to perforating epiphyseal vessels is necessary for their viability, but loss of these vessels does not cause hypertrophy. Since hypertrophy and calcification both occur in the proximity of perforating epiphyseal vessels in normocalcemic animals but not in hypocalcemic animals, it is likely that the vessels influence hypertrophy and calcification by delivering calcium to chondrocytes.

Animals↗

PubMed1995

Intervessel (arteries and veins) and heart/vessel selectivities of therapeutically used calcium entry blockers: variable, vessel-dependent indexes.

The intervessel selectivity indexes of the calcium entry blockers amlodipine, felodipine, isradipine, nicardipine, nifedipine, nitrendipine, diltiazem and verapamil were assessed by determining the potency of these compounds [concentration decreasing tension developed by KCl in blood vessels by 50% (bvlC50)] to relax several KCl-precontracted blood vessels (femoral, jugular and saphenous veins and left anterior descending and left circumflex coronary and renal arteries) precontracted with KCl. The concentrations of KCl (25 mM for arteries and 50 mM for veins) used gave a similar response in these vessels. Intervessel selectivity indexes are the ratios of the bvlC50 determined in two different vessels. The negative inotropic potency (hlC50) was ascertained in paced (2 Hz), isoproterenol-(10 nM) supported atrial strips, and for three of the compounds, in papillary muscles. This allowed calculation of heart/vessel selectivity or vasoselectivity (ratio of hlC50 and bvlC50). All compounds overcame almost entirely (85-100%) the vessel contractile response to KCl and strongly reduced (65-90%) the tension developed by myocardial preparations. The rank order for vasorelaxant potency (bvlC50 from approximately 1 to approximately 700 nM) was generally as follows: isradipine > or = nifedipine > or = nitrendipine > or = amlodipine > or = verapamil > or = felodipine > or = nicardipine > or = diltiazem. However, the rank order for negative inotropic potency (hlC50 spanning from approximately 200 to approximately 6000 nM) was isradipine > or = nifedipine > or = verapamil > or = diltiazem > or = amlodipine > or = nitrendipine > or = felodipine > or = nicardipine. All compounds were generally more potent in relaxing capacitance than conductance vessels. Furthermore, of the capacitance vessels, the jugular vein was the least susceptible to relaxation; among the conductance vessels, five of the eight compounds relaxed renal arteries with greater potency than coronary arteries. Consequently, the value of the heart/vessel selectivity index is intrinsically dependent on the vessel used to calculate it. Overall, nitrendipine was the most vasoselective calcium entry blocker studied, with selectivity indexes ranging from 28 to 523. In conclusion, 1,4-dihydropyridine calcium entry blockers generally have a much greater affinity for calcium channels present in micropig veins than in heart muscle myocytes. This is possibly due to tissue-specific features of L-type calcium channels. Finally, comparing the vasoselectivity index of various compounds has validity only if this index is calculated by using the same experimental procedure applied to the same vascular tissue and the same heart preparation taken from the same species.

Animals↗

PubMed1996

[Lymphoscintigraphy for non-invasive long term follow-up of functional outcome in patients with autologous lymph vessel transplantation].

AIM: Autologous lymph vessel transplantation significantly improves the lymphdrainage in patients with primary and secondary lymphedema. The aim of the present study was to answer the question, whether scintigraphic long-term follow up and semiquantitative evaluation of lymphatic flow could prove the persisting success of this sophisticated microsurgical technique. METHODS: In this study visual and semiquantitative lymphoscintigraphy was used to prove the function of lymphatic vessel grafts in 20 patients (17 females, 3 males) comparing a preoperative baseline study with postoperative follow up investigations for a period of 7 years. The reason for microsurgical lymph vessel transplantation was in 4 patients a primary and in 16 patients a secondary lymphedema. In 12 cases the transplantation site was at the upper extremity, in 8 cases at the lower limb. RESULTS: In 17/20 patients lymphatic function significantly improved after autologous lymph vessel transplantation compared to the preoperative findings, as verified by visual improvement of lymph drainage and decrease of a numeric transportindex. In 5 cases the vessel graft could be directly visualized. In these patients with scintigraphic visualization of the vessel graft the transportindex decreases to a significantly greater extent compared to the preoperative baseline study. Only 3 patients did not benefit from microsurgical treatment CONCLUSION: Lymphoscintigraphy combined with semiquantitative estimation of lymphatic transport kinetics has shown to be an easy, reliable and readily available technique to assess lymphatic function before and after autologous lymph vessel transplantation. Thus, the method is not only helpful in planning microsurgical treatment but also in monitoring the postoperative improvement of lymph drainage. Patients with scintigraphic visualization of the vessel graft showed a significant better postoperative outcome than those without. The scintigraphic visualization of the vessel graft therefore seems to indicate a favourable prognosis regarding to lymph drainage.

Adult↗

PubMed1997

Classical polyarteritis nodosa and microscopic polyarteritis with medium vessel involvement--a comparison of the clinical and laboratory features.

Microscopic polyarteritis may involve medium-sized and small blood vessels as well as arterioles, venules and capillaries. We have compared the clinical and laboratory features in patients with microscopic polyarteritis and medium vessel involvement, with the features found in patients with polyarteritis nodosa affecting medium vessels alone. In a 9-year period, 21 patients presented to our hospital with a form of polyarteritis. Seven had microscopic polyarteritis demonstrated histologically (6/7, 86%) and associated with dysmorphic urinary red cells (7/7, 100%), as well as medium vessel vasculitis demonstrated histologically (7/7) or by angiography (1/7, 14%). Five patients had polyarteritis nodosa with medium vessel vasculitis demonstrated histologically (3/5, 60%) or by angiography (2/5, 40%); and no evidence of a glomerular vasculitis on biopsy (2/7, 29%) or in the urinary sediment (0/7, 0%). The remaining 9 patients had microscopic polyarteritis but medium vessel involvement was not excluded by angiography. All patients with microscopic polyarteritis and medium vessel involvement had glomerular hematuria (> 100,000 glomerular RBC/ml), proteinuria > 0.5 g/24 hours), and an elevated serum creatinine (0.166 to 0.811 mmol/l). Other symptoms included fever (6/7, 86%), night sweats (5/7, 71%), gastrointestinal bleeding (4/7, 57%), proximal myopathy (3/7, 43%) and peripheral neuropathy (3/7, 43%). One patient (1/7, 14%) had hypertension. Anemia (6/7, 86%), a raised ESR (6/7, 86%), thrombocytosis (6/7, 86%), hypoalbuminemia (6/7, 86%) and abnormal liver function tests (6/7, 86%) were common. Two patients (29%) had an eosinophilia. All 5 individuals who were tested for ANCA were positive (2cANCA, 2pANCA and one pattern not described). In contrast, in patients with polyarteritis nodosa and medium vessel involvement alone, an elevated ESR was common (4/5, 80%) but fever (1/5, 20%), night sweats (0/5, 0%), proximal myopathy (1/5, 20%) and peripheral neuropathy (1/5, 20%) were seen infrequently; hypertension (1/5, 20%) and eosinophilia (1/5, 20%) were also uncommon; and ANCA were not demonstrated (0/3, 0%). Medium-sized vessel involvement is common in patients with microscopic polyarteristis, and these patients are more likely to have renal involvement and systemic symptoms, and be ANCA-positive, than patients with polyarteritis nodosa alone. Gastrointestinal symptoms are often seen in both groups.

Adult↗

PubMed1997

Vasa vasorum of blood and lymph vessels in the broad ligament of the sheep uterus analyzed by scanning electron microscopy.

The morphology of vasa vasorum of the blood and lymph vessels in the broad ligament of the uterus was examined in 12 adult ewes. The technique of vascular corrosion casts with the usage of Mercox resin allows multiple surveys of a three-dimensional organization of vascular networks under a scanning electron microscope (SEM). The study was appended by tissue pieces dried by the critical point method for SEM and semi-thin sections stained with toluidyne blue for light microscopy. Vasa vasorum surrounded both the larger vessels and the lymph vessels emanating from the ovary and the uterus. Significant differences in location and intensity of vasa vasorum in blood vessels were observed. They were less developed in the first part of the ovarian and the uterine arteries than in their smaller branches. Significantly large, two- or even three-layer vasa vasorum surrounded the ovarian and the uterine branches of the ovarian artery as well as the ovarian veins in the area of mesovarium. In the other areas of the broad ligament of the uterus, arterial vessels of similar sizes usually had a single-layer vasa vasorum. The lymph vessels leaving the ovary and uterus were surrounded by dense, although usually single-layed, microvascular network. The presence of vasa vasorum on relatively small blood and lymph vessels of the broad ligament of uterus indicates their particular functions that are probably connected with the estrous cycle or pregnancy and changes of blood flow rate entering the ovary and uterus. However, the presence of significantly developed, multi-layer vasa vasorum networks on only some of the blood vessels indicates that it is probably one of the vessels morphological adaptations to serve the counter-current transfer of biologically-active regulators in the area of the broad ligament of the sheep's uterus.

Animals↗

PubMed2007

Connexin26 expression is associated with lymphatic vessel invasion and poor prognosis in human breast cancer.

PURPOSE: Cx26, which is a constituent of the connexin family, has recently been shown to promote metastasis through enhancing the vascular invasion in mouse melanoma cells. In this study, we have investigated whether or not Cx26 expression is associated with vascular invasion and recurrences in human breast cancers. EXPERIMENTAL DESIGN: Cx26 expression was studied in 152 invasive breast cancers by immunohistochemistry. In order to investigate the blood vessel invasion and lymphatic vessel invasion with precision, immunohistochemical staining of blood vessels and lymphatic vessels was carried out using anti-CD34 and anti-D2-40 antibodies, respectively. RESULTS: Cx26 was positive in 51.3% (78/152) of the breast tumors. A statistically significant association was observed between Cx26 expression and large tumor size (P = 0.013) or high histological grade (P = 0.043). Frequency of blood vessel invasion was higher in Cx26-positive tumors (5.1%, 4/78) than in Cx26-negative tumors (1.4%, 1/74) though not statistically significant (P = 0.210). Lymphatic vessel invasion was significantly (P = 0.001) more frequent in Cx26-positive tumors (39.7%) than in Cx26-negative tumors (14.9%). Patients with Cx26-positive tumors showed a significantly (P < 0.001) poorer prognosis than those with Cx26-negative tumors. Multivariate analysis showed that Cx26 (P < 0.05) expression was an independent prognostic factor. CONCLUSIONS: Cx26 expression is associated with lymphatic vessel invasion, large tumor size, high histological grade, and poor prognosis in human breast cancers. Cx26 seems to enhance the metastasis probably through promoting the lymphatic vessel invasion. Cx26 might be clinically useful as a new prognostic factor.

Antibodies, Monoclonal↗

PubMed2006

Effect of everolimus-eluting stents in different vessel sizes (from the pooled FUTURE I and II trials).

The everolimus-eluting stent (EES) has been shown to significantly decrease neointimal proliferation at 6 months compared with the bare metal stent (BMS) in patients with de novo coronary lesions. We report mid-term outcomes based on different vessel sizes in the combined FUTURE I and II trials. In the prospective, randomized, FUTURE I trial (single center) and expanded FUTURE II trial (multicenter), 106 patients (107 lesions) were randomized to EESs (n = 49 lesions) or BMSs (n = 58 lesions). Patients were categorized into 3 groups based on preprocedure reference diameter as assessed by quantitative coronary angiography (small vessel < 2.75 mm, medium vessel 2.75 to 3.25 mm, and large vessel > 3.25 mm). At 6-month follow-up, EESs decreased in-stent late lumen loss (decreased rate range of 78% to 94%), resulting in significantly larger minimum lumen area as assessed by intravascular ultrasound (increased range of 34% to 42%) compared with the BMS across all vessel sizes. There were no cases of in-stent restenosis with EESs at any vessel size but 8 cases with BMSs (5 in small vessels). No stent thrombosis, aneurysm formation, or late stent incomplete apposition was observed in any group. The EES appears to be effective for treatment of de novo coronary lesions in decreasing neointimal proliferation at 6-month follow-up compared with BMSs, regardless of vessel size.

Aged↗

PubMed2006

Absence of blood and lymphatic vessels in the developing human cornea.

PURPOSE: The normal human cornea is devoid of both blood and lymphatic vessels and actively maintains this avascularity (corneal angiogenic privilege). Whether and when corneal angiogenic privilege is achieved during development is unknown. METHODS: This study analyzed whether the cornea is primarily devoid of both blood and lymphatic vessels during intrauterine development or whether secondary regression of pre-existing vessels occurs before delivery. Indirect double immunohistochemistry was performed on 4-microm serial pupil-optic disc sections of paraffin-embedded human eyes stillborn at gestational ages of 17 to 41 weeks with antibodies against von Willebrand factor (vWF; factor VIII-associated antigen) as a panendothelial marker and with antibodies against lymphatic vessel endothelial hyaluronate receptor 1 (LYVE1) as a marker specific for lymphatic vascular endothelium. RESULTS: Human corneas were devoid of both vWF+++/LYVE-1(-) blood vessels and vWF+/LYVE-1+++ lymphatic vessels at all time-points analyzed. In contrast, there were numerous blood and lymphatic vessels detectable in the adjacent conjunctiva. CONCLUSION: The normal human cornea is primarily avascular and devoid of both blood and lymphatic vessels. Corneal angiogenic privilege is already achieved very early during fetal intrauterine development. This suggests early and strong expression of both antiangiogenic and antilymphangiogenic factors in the human cornea during development.

Blood Vessels↗

PubMed2005

Prognostic value of lymphatic and blood vessel invasion in neuroendocrine tumors of the lung.

Few data on the influence of vessel invasion on the progression of neuroendocrine lung tumors are available. Because of the lack of specific markers, previous studies could not reliably discriminate lymphatic and blood vessels. By immunostaining for podoplanin, specific for lymphatic endothelium, and CD34 antigen, we assessed lymphatic and blood vessel invasion in 120 tissue specimens of patients with neuroendocrine lung tumors. Lymphovascular invasion was correlated with clinicopathologic parameters, and its prognostic relevance was evaluated. Lymphatic vessels were identified exclusively at the tumor invasion front, whereas blood capillaries were also seen within tumors. Lymphatic vessel as well as lymphatic and blood vessel invasion was prevalent in patients with high-grade neuroendocrine tumors and advanced tumor stages, closely associated with lymph node metastases (P < 0.0001). In univariate analysis, these two invasion types correlated with decreased disease-free survival (both P < 0.0001), whereas blood vessel invasion alone did not. In multivariate analysis, only tumor grade and lymph node status remained statistically significant factors for prognosis (P = 0.016 and P < 0.0001). Our results suggest that evaluation of lymphatic vessel invasion is important in neuroendocrine lung tumors serving as a prognostic parameter for disease-free survival.

Adolescent↗

PubMed2001

[Extracranial carotid artery bypass using artificial vessels--4 case reports].

We successfully completed extracranial carotid artery reconstruction in four cases (case 1: arteriosclerotic occlusion of the left common carotid artery between the origin at the aorta to just below the cervical bifurcation, case 2-4: combined removal of the carotid artery with malignant cervical tumor) using various types of synthetic vessels, e.g. 1) Double Velour Dacron, or 2) Expanded polytetrafluoroethylene. In case 2, Xenon CT under balloon occlusion was useful for revealing the indication for carotid artery reconstruction. Recent progress in the development of materials for use in synthetic vessels has remarkably improved the long-term patency of synthetic vessels, especially in medium to large size ones (larger than 6 mm in diameter). Synthetic vessels have the following advantages: 1. No need to harvest autogenous vessels, 2. An external shunt is available for patients with poor ischemic tolerance to temporary occlusion of the carotid artery, 3. A vessel of the most suitable size can be selected, 4. No risk of tumor invasion, 5. Easy suturing because the orifice of a synthetic vessel does not collapse. We report the usefulness, the indication for, and the surgical procedures of extracranial carotid artery bypass using synthetic vessels.

Blood Vessel Prosthesis↗

PubMed1999

Simultaneous irradiation and imaging of blood vessels during pulsed laser delivery.

BACKGROUND AND OBJECTIVE: Simultaneous irradiation and viewing of 10-120 microm cutaneous blood vessels were performed to investigate the effects of 2-micros 577-nm dye laser pulses. STUDY DESIGN/MATERIALS AND METHODS: A modified scanning laser confocal microscope recorded vessel response to different radiant exposures (J/cm2). Probit analysis determined the 50% probability ("threshold") radiant exposure necessary to cause embolized or partly occluding coagula, coagula causing complete blood flow stoppage, and hemorrhage. RESULTS: A statistically significant difference in the threshold radiant exposure existed for each damage category for blood vessels 10-30 microm in diameter, but not for larger vessels. For vessels over 60 microm, complete flow stoppage was unattainable; increasing laser pulse energy produced hemorrhage. In larger vessels, coagula often were attached to the superficial vessel wall while blood flowed underneath. Monte Carlo optical and finite difference thermal modeling confirmed experimental results. CONCLUSION: These results provide insight into the role of pulse duration and vessel diameter in the outcome of pulsed dye laser irradiation.

Angiography↗

PubMed1999

Contribution of O4+ oligodendrocyte precursors and astrocytes to the glial ensheathment of vessels in the rabbit myelinated streak.

The barrier properties and glial ensheathment of blood vessels in the retinal myelinated streak of adult New Zealand White rabbits were characterized at the ultrastructural level by intravascular injection of horseradish peroxidase (HRP) and immuno-electron microscopy with monoclonal antibody O4 and antibodies to glial fibrillary acidic protein (GFAP). Vessels within the myelinated streak did not leak HRP, and they exhibited tight junctions between adjacent endothelial cells. However, unlike their adult counterparts, the retinal blood vessels at postnatal day 18 exhibited substantial endocytotic activity. Both GFAP+ astrocytes and O4+ cells were evident surrounding the preretinal blood vessels of the myelinated streak. Furthermore, O4+ cells exhibited features indicative of high synthetic activity, including a large proportion of extended chromatin and prominent nucleoli within the nucleus, as well as a well-developed Golgi apparatus and numerous mitochondria in the cytoplasm. O4+ cells also exhibited variable quantities of heterochromatin, indicative of early stages of cellular differentiation. These observations are consistent with previous data showing that O4+ cells in the myelinated streak include oligodendrocyte precursor cells, pre-oligodendrocytes, and immature oligodendrocytes (Morcos Y, Chan-Ling T. Glia 21:163-182, 1997). The present data indicate that the preretinal vessels of the myelinated streak possess barrier properties typical of microvasculature in the central nervous system, and that both O4+ cells and astrocytes contribute to the glial ensheathment of these vessels. These vessels thus differ markedly from the leaky preretinal vessels associated with pathological conditions such as retinopathy of prematurity.

Animals↗

PubMedDate not supplied

Coronary vessel alterations following chronic carbon monoxide exposure in the adult rat.

Adult male rats were exposed to 500 ppm CO continuously for 30 days, while litter-mate controls remained in room air (AIR). Heart weight-to-body weight ratio and hematocrit were increased significantly. Right ventricle (RV) free wall thickness was increased significantly as was right to left heart diameter and average heart diameter. Cross-sectional areas of the left ventricle (LV) free wall, interventricular septum (S) and RV midway between the apex and base were increased significantly. Morphometric analysis of the CO-exposed and AIR hearts revealed no significant differences in the number of small (27-114 microns) or larger (> 114 microns) blood vessels in any region; however, there was a trend towards an increased number of the smaller vessels, both arterioles and venules, in the CO-exposed rats. The larger arteries in the S and RV were significantly larger in the CO-exposed rats. There was a significant overall effect of CO on larger artery diameter across all heart regions, consistent with the appearance of heart radiographs taken. There were no differences in the diameter of the small vessels in any region of the heart between the CO-exposed and AIR rats. The vessel cross-sectional area of the larger vessels tended to be increased in all regions of the heart. The cross-sectional area of the large arteries in the LV was increased significantly. Arterial wall thickness was decreased significantly in RV and there was a significant overall effect of CO in decreasing wall thickness and the ratio of wall thickness-to-vessel luminal diameter in these vessels. No vascular pathology was observed. The results of this study suggest changes in coronary vessel architecture during chronic CO-induced cardiac hypertrophy and are consistent with earlier hemodynamic and morphometric studies of CO-exposed hearts.

Animals↗

PubMed2003

Initial experiences with in vivo intravascular coronary vessel wall imaging.

PURPOSE: To evaluate potential use of a loopless internal receiver coil for in vivo coronary artery vessel wall imaging in five domestic swine. MATERIALS AND METHODS: Intravascular free-breathing black blood coronary vessel wall imaging was performed using a previously described double inversion fast spin echo technique after x-ray guided placement of an internal receiver coil in or in close proximity to the target vessel (LAD, LCX). RESULTS: Image quality using the phased array coil was reproducible, while image quality with the internal receiver coil was heavily dependent on coil position with respect to the examined artery, and likely also dependent on blood flow and/or cardiac-related coil motion. With internal coil placement in the left circumflex coronary artery, images of the left anterior descending vessel wall appeared similar or superior compared to commercially available phased array surface coil images. With coil placement in the target vessel itself, imaging was suboptimal because of the extremely high signal intensity (hotspot) in close proximity to the vessel wall, leading to low contrast between the vessel wall and the surrounding tissues and blood. CONCLUSION: In this study, we demonstrate the feasibility of in vivo intravascular coronary vessel wall imaging. Continued research is necessary to minimize coil motion and optimize coil sensitivity algorithms.

Animals↗