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Biomedical subjects

G Re

Publications and source records attributed to G Re.

At least 109 records · Page 6Linked to original sources
PubMed1983

Histometric analysis of sheathed capillaries in congestive splenomegaly.

The structural rearrangement of human sheathed capillaries in congestive splenomegaly with hypersplenism has been evaluated by histometric analysis. In abnormal spleens the external diameter and the wall thickness were decreased, while the internal diameter was increased. Moreover, the total length and the absolute number of sheathed capillaries were increased, though not to the same high degree as the volume of the whole red pulp. Thus, in addition to the well-known changes of the sinuses, also the terminal arterial passages appear to participate in the morphological rearrangement of the red pulp in congestive splenomegaly.

Adolescent↗
PubMed1982

Carotid wall as an isotropic mechanical system.

The morphological organization of the structural components in the dog carotid wall is investigated by X-ray diffraction and microscopic analysis. Histological analysis confirms an anisotropic morphology of smooth muscle cells and elastic fibers in the tissue. Collagen fibers, as revealed by X-ray diffraction technique, are organized in an isotropic network in the unstretched carotid media. Collagen fibers stretch without a preferential direction of orientation when a carotid segment is deformed in the physiological range under intraluminal pressure. A mathematical model which takes into account the isotropic distribution of the collagen fibers is developed. The validity of this model has been tested by computing several mechanical parameters using Anliker's data on the axial and radial oscillation obtained for carotids of living dogs. In spite of the anisotropic morphology of the main constituents of the carotid media layer, from a mechanical point of view the tissue can be considered as an isotropic material for the random distribution of the collagen fibers which represent the component of higher tensile strength.

Animals↗
PubMed1980

[Vascular flow-regulating devices in the human kidney].

Small arterious and venous vessels of the juxtamedullary cortex of normal human kidney present wall formations regulating the blood flow. The arterious devices appear either as sphincterial rings at the origins of collateral branches of interlobular arteries, or as groups of myoepithelioid cells in the wall of small arteries immediately preceding the afferent arterioles. The venular devices consist of circular muscular thickenings repeated along the course of the vessel.

Adult↗
PubMed1980

[The presence of arteriovenous anastomoses in the human kidney].

The microscopic observation of serial sections obtained from normal human kidneys allowed to demonstrate the presence of arteriovenous anastomoses in the juxtamedullary cortex. In particular one section is shown which clearly presents an anastomotic channel along with its connections to both an afferent arteriole and a venule.

Adult↗
PubMed1980

[Mechanical properties of the human basilar artery].

The mechanical properties of the wall of human basilar artery have been determined by tension tests. The degree of orientation of collagen fibers inside the deformed arterial wall has been evaluated by the analysis of the mechanical results and by the X-ray diffraction pattern. The results show that the wall of the muscular arteries can be considered a "composite material" which mechanical properties, at high stress, are due mainly to the collagen fibers orientation.

Basilar Artery↗
PubMed1980

[Role of the orientation of the collagen fibers on the mechanical properties of the carotid wall].

Mechanical test was applied to several carotid walls air-dried under different degree of deformation along the circumferential direction. The stress-strain curves show an increase of the elastic modulus as a function of the deformation. X-ray diffraction studies were applied to determine the degree of collagen orientation in the deformed samples. The carotid wall, in agreement with the "composite materials theory", shows that the collagen is the most responsible factor of the mechanical properties of the tissue.

Animals↗
PubMed1980

[Collagen fiber orientation in the tunica media of the aorta as a function of intraluminal pressure].

X-ray diffraction investigation and hystological analysis have been carried out on segments of pig's aortic media layer under different values of distending pressure. The roentgenografic study shows that collagen fibers aligne themselves along the circumferential direction of the vessel as a function of the intraluminal pressure and are completely oriented at systolic pressure. Hystological analysis reveales that the smooth cells orientation, as a function of intraluminal pressure, is very close to that of collagen fibers.

Animals↗
PubMed1980

[Roentgenographic study of the structural organization of the collagen fibers in the tunica media of the aorta].

X-ray diffraction tecnique was used to investigate the distribution and orientation of collagen fibers in media layer of pig aortic wall as a function of mechanical deformation. Hyistological analyses were carried out to study the behavior of smooth cells when mechanical deformation is applied to media layer. The results show a close relationship between collagen fibers and smooth cells orientation.

Animals↗