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At least 253 records · Page 14Linked to original sources
PubMed2006

Temporo-spatial distribution of blood vessels in human lumbar intervertebral discs.

While there is consensus in the literature that blood vessels are confined to the outer anulus fibrosus of normal adult intervertebral disc, debate continues whether there is a vascular in-growths into inner parts of the intervertebral disc during degeneration. We therefore tested the hypothesis that vascular in-growth is not a distinct feature of disc degeneration. The specific endothelial cell marker CD 31 (PECAM) was used to immunohistochemically investigate 42 paraffin-embedded complete mid-sagittal human intervertebral disc sections of various ages (0-86 years) and varying extent of histomorphological degeneration. Additionally, 20 surgical disc samples from individuals (26-69 years) were included in this study. In discs of fetal to infantile age, blood vessels perforated the cartilaginous end plate and extended into the inner and outer anulus fibrosus, but not into the nucleus pulposus. In adolescents and adults, no blood vessels were seen except for the outer zone of the anulus fibrosus adjacent to the insertion to ligaments. The cartilaginous end plate remained free of vessels, except for areas with circumscribed destruction of the end plate. In advanced disc degeneration, no vessels were observed except for those few cases with complete, scar-like disc destruction. However, some rim lesions and occasionally major clefts were surrounded by a small network of capillary blood vessels extending into deeper zones of the anulus fibrosus. A subsequent morphometric analysis, revealed slightly "deeper" blood vessel extension in juvenile/adolescent discs when compared to young, mature and senile adult individuals with significantly "deeper" extension in the posterior than anterior anulus. The analysis of the surgical specimens showed that only sparse capillary blood vessels which did not extend into the nucleus pulposus even in major disc disruption. Our results show that vascular invasion deeper than the periphery was not observed during disc degeneration, which supports the hypothesis that vascular in-growth is not a distinct feature of disc degeneration.

Adolescent↗
PubMed1980

Morphologic study on the interaction between the blood vessel wall and the blood flow: the arterial branching ostium and the site of permeability.

Regional permeability of the aortas (particularly branching portion) in the human and the rabbit was investigated. In the experiment for examining the permeability into the branching portion of the human aortas the permeability in a shape of an upside down triangle was found in the lower region of the ostia. The shape of this penetration highly resembled the shapes of the lesion of arteriosclerosis and lipid deposition. In the rabbit aortas the permeability of intravenously injected Evans blue occurred most strongly in the lower region of the opening of the intercostal arterial branch. The shape of the permeability was similar to that of the lipid deposition in the rabbit fed with 1% cholesterol. In the lower region of the branching portion of intercostal artery of the rabbit, the degenerative change of the endothelium was observed more frequently than in other regions. The feeding with 1% cholesterol was found to facilitate this degenerative change.

Animals↗
PubMed1996

Reduced capacity of tumour blood vessels to produce endothelium-derived relaxing factor: significance for blood flow modification.

The effect of nitric oxide-dependent vasodilators on vascular resistance of tumours and normal tissue was determined with the aim of modifying tumour blood flow for therapeutic benefit. Isolated preparations of the rat P22 tumour and normal rat hindlimb were perfused ex vivo. The effects on tissue vascular resistance of administration of sodium nitroprusside (SNP) and the diazeniumdiolate (or NONO-ate) NOC-7, vasodilators which act via direct release of nitric oxide (NO), were compared with the effects of acetylcholine (ACh), a vasodilator which acts primarily via receptor stimulation of endothelial cells to release NO in the form of endothelium-derived relaxing factor (EDRF). SNP and NOC-7 effectively dilated tumour blood vessels after preconstriction with phenylephrine (PE) or potassium chloride (KCl) as indicated by a decrease in vascular resistance. SNP also effectively dilated normal rat hindlimb vessels after PE/KCl constriction. Vasodilatation in the tumour preparations was accompanied by a significant rise in nitrite levels measured in the tumour effluent. ACh induced a significant vasodilation in the normal hindlimb but an anomalous vasoconstriction in the tumour. This result suggests that tumours, unlike normal tissues are incapable of releasing NO (EDRF) in response to ACh. Capacity for EDRF production may represent a difference between tumour and normal tissue blood vessels, which could be exploited for selective pharmacological manipulation of tumour blood flow.

Acetylcholine↗
PubMed2003

Distribution of the epithelial rests of Malassez and their relationship to blood vessels of the periodontal ligament during rat tooth development.

BACKGROUND: There is some evidence that the epithelial cell rests of Malassez partition the root surface from the periodontal ligament blood vessels, and may protect the root from resorption. OBJECTIVE: The aim of the present study was to determine the distributions of the epithelial rests of Malassez (ERM) and blood vessels in the periodontal ligament (PDL) of the developing rat first molar before, during and after emergence. METHODS: Four Sprague-Dawley rats were sacrificed at two days, one week, two weeks, three weeks, four weeks and six weeks of age. After processing, the maxillae were embedded in paraffin, and sectioned longitudinally and transversely. The sections were stained with a double immuno-histochemical technique which utilised a keratin antibody AE1-AE3 (1:2,000) and an endothelial antibody Factor VIII (1:10,000) to enable simultaneous labelling of ERM and blood vessels. ERM and blood vessel counts were obtained from the mesio-buccal roots of three week, four week and six week-old rats, whilst qualitative observations were made for the earlier developmental stages. RESULTS: ERM cells and cell clusters were found in the tooth third of the PDL width at the three, four and six week stages. Cells and cell clusters increased in number with age, especially in the upper third of the mesio-buccal root. The largest numbers of cells and clusters were found on the distal surfaces of the roots in all age groups. Cells and clusters in all root surfaces increased from three to four weeks, but decreased from four to six weeks. The greatest number of blood vessels was found in the bone-side third of the PDL. The distal surface had the highest proportion of blood vessels, and the palatal surface the least proportion. The number of blood vessels in all surface quadrants did not vary much from three to four weeks of age, but increased from four to six weeks of age, possibly as a reaction to tooth emergence and occlusal function. Physiological root resorption was only observed after tooth emergence, and appeared to be related to loss of continuity of the ERM network and the incursion of blood vessels. CONCLUSIONS: Orthodontic root resorption can be regarded as an exaggerated response to loss of PDL homeostatic control, possibly mediated by the epithelial rests of Malassez.

Age Factors↗
PubMed1997

The effect of inflammation on blood vessel area in Rosenthal's canal in the cat cochlea.

The quantitative analysis of spiral ganglion cells is important. It is conventionally expressed as a cell density, the number of cells within Rosenthal's canal divided by its area. The area of Rosenthal's canal conventionally excludes the areas of blood vessels within it. If blood vessels proliferate in an inflammatory response then excluding their area may result in an under-estimate of cell loss. This study investigates whether blood vessel area increases with inflammation. Eighteen implanted and stimulated cat cochleas were studied. Using computer aided analysis techniques we measured the areas of Rosenthal's canals and its blood vessels. A histologist quantitatively graded the inflammation in each cochlea. Blood vessel area increased with the grade of inflammation. Multiple regression analysis showed this effect was significant (P < 0.01). This increase in blood vessel area may have an effect on density measurements made by excluding that area, leading to an under-estimate of ganglion cell loss.

Animals↗
PubMed1981

[Functional significance and modeling of spiral-shaped blood vessels].

Models to demonstrate and study changes in the blood vessels forms under contractile effect of the smooth muscle fibres and mechanisms performing fluid transport in the model vessels when their form and changes are demonstrated. As the smooth muscle fibres can twist in opposite directions, the blood vessels can also spiral in opposite directions and spasm at various places along their length, thus performing blood transport. How the changes in the form affect the blood transport is demonstrated. Owing to the modelling the phenomenon of a directed fluid movement in closed spiral-shaped channels has been stated and it has been proved that the directed fluid movement depends on a disturbed equilibrium state of the fluid when it is subjected to a combined effect of the Earth gravitation and thermal irradiation. It has been stated that the directed fluid movement in the spiral shaped channels depends on their orientation towards the gravitational vector and absorbtion of the energy by the fluid in some coils of these channels. It is possible to conclude that the spiral-shaped form of the blood vessels and its enantiomorphism are morphological properties of tissues and they play an important role in hemodynamics, thermoregulation and interconnection with certain external effective factors.

Biophysical Phenomena↗
PubMed1995

Large blood vessel cooling in heated tissues: a numerical study.

Large blood vessels can produce steep temperature gradients in heated tissues leading to inadequate tissue temperatures during hyperthermia. This paper utilizes a finite difference scheme to solve the basic equations of heat transfer and fluid flow to model blood vessel cooling. Unlike previous formulations, heat transfer coefficients were not used to calculate heat transfer to large blood vessels. Instead, the conservation form of the finite difference equations implicitly modelled this process. Temperature profiles of heated tissues near thermally significant vessels were calculated. Microvascular heat transfer was modelled either as an effective conductivity or a heat sink. An increase in perfusion in both microvascular models results in a reduction of the cooling effects of large vessels. For equivalent perfusion values, the effective conductivity model predicted more effective heating of the blood and adjacent tissue. Furthermore, it was found that optimal vessel heating strategies depend on the microvascular heat transfer model adopted; localized deposition of heat near vessels could produce higher temperature profiles when microvascular heat transfer was modelled according to the bioheat transfer equation (BHTE) but not the effective thermal conductivity equation (ETCE). Reduction of the blood flow through thermally significant vessels was found to be the most effective way of reducing localized cooling.

Animals↗
PubMed2001

Structural fragility of blood vessels and peritoneum in calponin h1-deficient mice, resulting in an increase in hematogenous metastasis and peritoneal dissemination of malignant tumor cells.

We have observed weak expression of calponin h1, which stabilizes the actin filament system, in blood vessels within human malignant tumors. This observation suggested that because of a deficiency in stabilization by calponin h1, the structure of blood vessels in malignant tumors is fragile compared with blood vessels in normal tissues. We therefore generated calponin h1-deficient (CN(-/-)) mice to examine the effect of calponin h1 on the integrity of the barrier system in blood vessels against cancer metastasis. The CN(-/-) mice exhibited morphological fragility of the tissues, including the uterus and blood vessels. In particular, we frequently observed bleeding into the surrounding tissue from blood vessels of the ocular fundus in CN(-/-) mice. In addition, mesothelial cells, which usually express calponin h1 in normal (CN(+/+)) mice, were retracted in the CN(-/-) mice. When fluorescein was injected i.v. into mice, the CN(-/-) mice exhibited a greater and more rapid leakage of fluorescein from the blood vessels of the ocular fundus compared with the CN(+/+) mice. In the CN(-/-) mice receiving i.v. inoculations of B16 melanoma cells, significantly more metastatic nodules were formed in the lung than in the CN(+/+) mice. When B16 melanoma cells were injected i.p., the severity of peritonitis carcinomatosa was greater in CN(-/-) than in CN(+/+) mice. These results indicate that calponin h1 plays an important role in the regulation of the integrity of the blood vessels and peritoneum, which in turn is an important factor influencing the frequency of cancer metastasis. The CN(-/-) mice, which exhibit fragile blood vessels and peritoneum, could serve as sensitive and useful host models to investigate cancer metastasis.

Actins↗
PubMed1990

Prognostic significance of peritumoral lymphatic and blood vessel invasion in node-negative carcinoma of the breast.

The prognostic significance of intramammary lymphatic and blood vessel invasion was evaluated in a retrospective series of 221 patients with node-negative carcinoma of the breast treated with modified radical mastectomy. To facilitate identification of lymphatic and blood vessel invasion, the tumors were studied with an immunohistochemical technique using antibodies to endothelial markers. Peritumoral lymphatic and blood vessel invasion (PLBI) (encompassing both lymphatic and blood vessel invasion) was an adverse prognostic indicator independent of menopausal status, tumor size, and other histologic variables. Recurrence of disease and death resulting from carcinoma were significantly higher for patients with PLBI-present (+) tumors compared with patients with PLBI-absent (-) tumors (P less than .0001). The risk of recurrence for patients with PLBI+ tumors was 4.7 times that for their PLBI- counterparts. The presence of intratumoral lymphatic and blood vessel invasion (ILBI) is less important because few examples were found without concomitant PLBI. When PLBI was separated into lymphatic invasion and blood vessel invasion individually, the prognostic significance was retained in both groups. The immunohistochemical approach reduced both false-negative and false-positive observations and identified about 40% of PLBI that would have been missed by routine histologic examination alone. The presence of PLBI appears to be a potentially useful discriminant in predicting the outcome of patients with node-negative carcinoma of the breast.

Breast Neoplasms↗
PubMed1986

Effects of salicylate and steroid on neutrophil migration and corneal blood vessel growth.

Cauterization of the cornea results in emigration of neutrophils from the limbal blood vessels into the corneal tissue. Blood vessel proliferation follows, the stimulus for which is unknown. In this study, 0.1 M sodium salicylate drops administered topically to cauterized rat corneas over a 48-h period had an inhibitory effect on the migration of neutrophils from the limbal vessels 6 h after injury, but this was not maintained at 48 h. After 6 days of treatment, the salicylate had no effect on vessel growth into the cauterized rat cornea. Application of prednisolone disodium phosphate ointment to cauterized corneas also inhibited neutrophil migration at 6 h, but increased the extravascular neutrophils at 48 h. After 6 days of treatment, corneal blood vessel growth was significantly reduced. It was concluded that there is no consistent relation between the number of extravascular neutrophils at the corneal limbus and the extent of corneal blood vessel growth.

Animals↗
PubMed1989

Histopathology of primary pulmonary hypertension. A qualitative and quantitative study of pulmonary blood vessels from 58 patients in the National Heart, Lung, and Blood Institute, Primary Pulmonary Hypertension Registry.

Qualitative and quantitative studies were performed on pulmonary blood vessels in lung tissue obtained by biopsy, pneumonectomy, or autopsy from 58 patients in the Registry of Primary Pulmonary Hypertension sponsored by the Heart, Lung, and Blood Institute of the National Institutes of Health. In 49 patients (84%), the hypertensive vascular disease involved predominantly or exclusively muscular pulmonary arteries and arterioles. In each of these 49 patients, pulmonary artery medial hypertrophy was observed, and in 48 patients, it was also associated with intimal or luminal lesions. On the basis of the predominant histopathologic features, 25 of the 48 patients were classified as having pulmonary arteriopathy with plexiform lesions characterized by a combination of concentric laminar intimal fibrosis, eccentric intimal fibrosis, and plexiform lesions; in nine of these 25, recanalized thrombi were also present. Pulmonary arteriopathy with thrombotic lesions, defined by the presence of both eccentric intimal fibrosis and recanalized thrombi but without plexiform lesions, was observed in 19 patients. Intimal fibrosis, either concentric or eccentric, without plexiform or thrombotic lesions was found in four patients. Among the remaining nine patients in the Registry, pulmonary veno-occlusive disease was present in seven and chronic pulmonary venous hypertension in one. Pulmonary blood vessels were microscopically normal in a lung biopsy specimen from another patient. In general, patients with plexiform lesions and those with veno-occlusive disease had a much poorer prognosis than patients with thrombotic lesions. The present study shows the existence of several distinct histopathologic patterns of pulmonary vascular disease in individuals with primary pulmonary hypertension diagnosed by standardized clinical and laboratory criteria.

Humans↗
PubMed2005

A technique to detect and to quantify fasciocutaneous blood vessels in small laboratory animals ex vivo.

PURPOSE: A microangiographical technique is described, which allows visualization of small and capillary blood vessels and quantification of fasciocutaneous blood vessels by means of digital computer analysis in very small laboratory animals. MATERIALS AND METHODS: The left carotid artery of 20 nu/nu mice was cannulated (26 gauge) and a mixture of gelatin, bariumsulfate, and green ink was injected according to standardized protocol. Fasciocutaneous blood vessels were visualized by digital mammography and analyzed for vessel length and vessel surface area as standardized units [SU] by computer program. RESULTS: With the described microangiography method, fasciocutaneous blood vessels down to capillary size level can be clearly visualized. Regions of interest (ROIs) can be defined and the containing vascular network quantified. Comparable results may be obtained by calculating the microvascular area index (MAI) and the microvascular length index (MLI), related to the ROIs size. Identical ROIs showed a high reproducibility for measured [SU] < 0.01 +/- 0.0012%. CONCLUSION: Combining microsurgical techniques, pharmacological knowledge, and modern digital image technology, we were able to visualize small and capillary blood vessels even in small laboratory animals. By using our own computer analytical program, quantification of vessels was reliable, highly reproducible, and fast.

Angiography↗