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Biomedical subjects

A Ruggeri

Publications and source records attributed to A Ruggeri.

At least 109 records · Page 6Linked to original sources
PubMed1985

Pharmacokinetics and distribution of a fluoresceinated glycosaminoglycan, sulodexide, in rats. Part II: Organ distribution in rats.

Fluorescein-labelled sulodexide tissue distribution was studied in the rat after intravenous administration at the dosage of 15 mg/kg. A globular fluorescence was observed mainly in the extracellular matrix and a diffuse one was present in liver and kidney parenchyma lasting for a long time, up to 4 h after administration. In particular in the kidney cortex the fluorescent material was present at the higher time intervals. Fluorescence was also observed in the spleen and in the perivascular areas and in the media of the aortic wall.

Animals↗
PubMed1984

Pulsed electromagnetic fields increase the rate of rat liver regeneration after partial hepatectomy.

Pulsed extremely low-frequency electromagnetic fields interact with rat liver regeneration following partial hepatectomy when delivered to the rats immediately after the operation and every 12 hr thereafter. This interaction results first in an increased ornithine decarboxylase activity, an enzyme used as an early marker of cell growth. The rate of labeled thymidine incorporation into DNA is also increased by the treatments with magnetic fields during the early phases of liver regeneration. Glycogen depletion and lipid accumulation, two well-known early peculiar phenomena of liver regeneration following partial hepatectomy, are quantitatively decreased by the treatments with electromagnetic fields. The recovery to normal glycogen and lipid contents is completed within 5 days after surgery, instead of 7 days as found in control rats.

Animals↗
PubMed1984

Heterogeneity of proteoglycan particles in thin sections and replicas of human articular cartilage.

Proteoglycans were studied in articular cartilage of human femoral condyles. On the basis of the histochemical data obtained by means of light microscopy (AB + CEC MgCl2; pre-incubation with hyaluronidase or with chondroitinase ABC), the proteoglycan concentration as well as the keratan sulfate-chondroitin sulfate ratio seemed to increase proportionally to the articular cartilage depth. AB-proteoglycan particles of various shapes (filament-like or leaf-like) and sizes (10 nm or 16-18 nm), depending on the articular cartilage depth and on the histochemical conditions (as above), were visualized in thin sections. Similar heterogeneity of elongated non-collagen particles was shown in replicas of fresh freeze-fractured and deep-etched specimens. An interpretation of the distribution and nature of articular cartilage proteoglycans was made by comparing the obtained morphological findings.

Adolescent↗
PubMed1984

Influence of pulsed electromagnetic fields on regenerating rat liver after partial hepatectomy.

Partially hepatectomised rats have been exposed immediately after surgery and every 12 hours thereafter to pulsed extremely low frequency electromagnetic fields. Stereological analysis performed on electron micrographs has shown that the treatment limits the depletion of liver glycogen found in control untreated rats within the first post-operative day. The massive accumulation of lipid droplets found in control rats is also limited to about one half by exposing the animals to pulsed magnetic fields. The time taken for glycogen and lipid content to recover to values found at zero time decreases from seven to five days in animals undergoing treatment with pulsed electromagnetic fields. The liver wet weight and the total protein content show a pattern of changes which is consistent with the behaviour of glycogen and lipid content. Five days after operation the treated rats reach the values found at zero time, while control animals need seven days to reach the same values.

Animals↗
PubMed1983

Arrangement of microfibrils in collagen fibrils of tendons in the rat tail. Ultrastructural and x-ray diffraction investigation.

The microfibrillar arrangement in collagen fibrils of tendons in the tail of the rat was examined by electron microscopy and X-ray diffraction. Fresh and air-dried collagen fibers were examined in unstretched and stretched conditions. The results demonstrate that the microfibrils have a course parallel to the longitudinal axis of the collagen fibrils. The influence of stretching and hydration of the samples on the orientation of fibrils and microfibrils is also assessed.

Animals↗
PubMed1983

Light microscopy, electron microscopy, and X-ray diffraction analysis of glycerinated collagen fibers.

Light microscopy, transmission electron microscopy (freeze-fracture replicas and thin sections), and X-ray diffraction techniques were used to investigate the structure of rat tail tendon collagen fibers subjected to one of the following treatments: water, phosphate buffer, glutaraldehyde, glutaraldehyde followed by glycerol, glycerol, and glycerol followed by phosphate buffer. As seen by light microscopy, only treatment with glycerol induces a remarkable swelling of the native (untreated) collagen specimens. Replicas and thin sections show that this swelling is due to an expansion of the interfibrillar space, and to a dissociation of the collagen fibrils into microfibrils. X-Ray diffraction analysis reveals great disorder in the glycerol-swollen collagen fibers. However, this does not appreciably involve the microfibrillar and molecular structure. Light and electron microscopy as well as X-ray diffraction techniques show that the collagen fiber swelling induced by glycerol is an almost completely reversible process.

Animals↗
PubMed1983

Is the "pool-fraction" paradigm a valid model for assessment of in vivo turnover in non-steady state?

Quantification of in vivo turnover of endogenous substances in nonsteady state is of fundamental importance for understanding a variety of physiological and clinical metabolic situations. Toward this end, a pool-fraction model has become a paradigm in the glucose and ketone body areas. We discuss the basic assumptions on which the pool-fraction model is based and the criteria on which it has been validated. Specific comments are then made on its current and potential use for quantifying the non-steady-state turnover of glucose, ketone bodies, and insulin. We conclude that the quantitative reliability of predictions provided by the pool-fraction model is quite poor and that new developments are needed for quantifying the non-steady-state situation.

Animals↗
PubMed1983

The banding pattern of rat tail tendon freeze-etched collagen fibrils.

Banding patterns of freeze-etched and replicated rat tail tendon collagen fibrils were studied. Better banding definition was obtained by freezing the samples without using a cryoprotectant and by prolonging etching. Under these conditions, the banding pattern was characterized by a sequence of elevated and depressed segments with a D-period of 65 nm, by two ridges at the margins of the elevations and by a third ridge at an intermediate point in the depressions. A comparison between replicas and isolated negatively stained collagen fibril micrographs as well as densitometric determinations have allowed interpretation of the elevations and depressions as overlap and gap zones and of the three ridges as the main bands with higher molecular density. Estimates, carried out on densitometric diagrams obtained from replicas, gave values which may represent a new parameter in the study of collagen banding and led to the calculation of a 0.55 D long gap zone and of a 0.45 D long overlap zone.

Animals↗
PubMed1982

Pseudo-elastica in alcoholic hepatic fibrosis: histochemical and ultrastructural aspects.

During the early phases of alcoholic hepatic fibrosis, histochemical studies show positivity to both specific elastin and the specific collagen stains at the level of the centrolobular vein, the portal triad and portacaval anastomosis. Ultrastructural investigation in the portacaval anastomosis demonstrates the presence of collagen fibrils and afibrillar material. Treatment with tannic acid increases the contrast of these structures. The possible correlations between histochemical and ultrastructural findings are discussed.

Collagen↗
PubMed1981

A modeling study of the effect of fasting on bilirubin kinetics in Gilbert's syndrome.

The mechanism of fasting hyperbilirubinemia (FH) is not fully understood. We investigated basal bilirubin kinetics in 20 Gilbert's patients and in 7 healthy volunteers. The study was repeated in seven of these Gilbert's patients after 48-h fasting. A two-compartment model proved to be adequate for interpreting crystalline bilirubin kinetics in these individuals. The parameters of bilirubin kinetics were estimated by employing a maximum likelihood parameter estimation technique. Consistency of the model and uniqueness of the estimated parameter values (from the covariance matrix) were shown. Our results confirmed previous observations regarding impaired bilirubin kinetics in Gilbert's patients as compared to controls. The main results obtained from kinetic studies in Gilbert's patients after fasting were i) no modification in the bilirubin clearance, and ii) a more than twice increase of bilirubin turnover. These data indicate that FH is related to an increased bilirubin production (mainly intrahepatic). Furthermore, evidence arises from this study that the bilirubin tolerance test is a useful diagnostic test for Gilbert's syndrome.

Adolescent↗
PubMed1981

[Contrast radiographic study of ductal pathology of the breast].

On the basis of personal experience, the possibility and the limits of galactography are discussed. Galactography has been used by the authors in any cases of discharge from the nipple, and has shown to be the only radiological examination able to discover intraductal tumours. Furthermore it allows to establish the site and extension of the lesions. Among the limits of the method the impossibility to distinguish between benign and malignant lesions is stressed out.

Breast Diseases↗
PubMed1981

Differences in the microfibrillar arrangement of collagen fibrils. Distribution and possible significance.

The microfibrillar arrangement of collagen fibrils has been studied on replicas of freeze-fractured specimens and on thin sections of specimens treated with a 4.0 M guanidinium chloride solution. Collagen fibrils with straight arrangement of their microfibrils usually have a variable diameter and correspond in their distribution to genetical type I and type II collagens. Collagen fibrils with helicoidal arrangement of their microfibrils present a relatively small and uniform diameter and show a tissue distribution similar to that of the genetical type III collagen. The corneal stroma, although predominantly composed of type I collagen, displays collagen fibrils with a helicoidal microfibrillar arrangement, and small uniform diameter. This exception can be explained in consideration of the function of the collagen of the corneal stroma. A close correlation between all the different microfibrillar patterns of the collagen fibrils and their function in the anatomical sites we examined is evident.

Animals↗
PubMed1979

Biochemical and structural abnormalities of the connective tissue in Larsen's syndrome.

Skin, iliac crest cartilage and tendon of a patient affected with Larsen's syndrome were subjected to biochemical and ultrastructural investigation. A substantial increase in the ratio of glucosamine to galactosamine was found both in skin and cartilage. Ultrastructural abnormalities of collagen fibres and proteoglycan filaments were also found in Larsen's tissues. The significance of these findings are discussed.

Cartilage↗