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Biomedical subjects

R Ricci

Publications and source records attributed to R Ricci.

At least 163 records · Page 9Linked to original sources
PubMed1990

Type II oestrogen binding sites in human colorectal carcinoma.

Seven cases of colorectal adenocarcinomas were investigated for the presence of oestrogen receptors and progesterone receptors. The tumours specifically bound oestradiol. This binding almost exclusively resulted from the presence of high numbers of type II oestrogen binding sites. Oestrogen receptors were absent or present at very low concentrations. Immunohistochemical investigation of nuclear oestrogen receptors gave negative results. This indicates that antioestrogen receptor antibodies recognise oestrogen receptors but not type II oestrogen binding sites. The presence of specific type II oestrogen binding sites and progesterone binding offers further evidence for a potential role for these steroids and their receptors in colorectal carcinoma.

Adenocarcinoma↗
PubMed1990

Interleukin-2 receptor expression in human mast cells and basophils.

Surgical human thymus, upper respiratory tract, lung and small and large bowel specimens were analyzed for the presence of interleukin 2 receptor (IL2-R)-positive cells. Histochemical (toluidine) and immunologic (anti-IL2-R monoclonal antibody) staining procedures revealed a distinct anti-IL2-R positivity in most of metachromatically staining cells. These positive cells were observed not only in tissues showing strong inflammatory reaction and mast cell hyperplasia, as in Crohn's disease, but also in those not histologically affected by pathologic conditions. This finding suggested that human mast cells, like T blast cells, express the p55 chain of IL2-R on their surface. To see whether IL2-R was being actively synthesized, a cell preparation rich in peripheral blood basophils (PBB), which are cells closely related to mast cells, was obtained. Ultrastructural analysis of PBB after indirect immunogold procedure revealed that the vast majority expressed the IL2-R. Moreover, the presence of intracellular reaction products in the cytoplasm of most membrane-positive PBB was indicative of active antigen synthesis. Furthermore, Northern blot analysis evidenced specific IL2-R mRNA in PBB, while its expression was augmented several times when PBB were cultured in the presence of stimulated T cell supernatant.

Animals↗
PubMed1989

Long-term pressure-induced cardiac hypertrophy: capillary and mast cell proliferation.

To determine whether a prolonged duration of mechanical load on the ventricular myocardium leads to capillary proliferation, constriction of the pulmonary artery was produced in rats at 3 mo of age, and the hearts were examined 200 days later. Functionally, elevations of right ventricular systolic pressure, from 30 +/- 12 to 67 +/- 11 mmHg, and right ventricular end-diastolic pressure, from 2.4 +/- 1.4 to 8.6 +/- 2.4 mmHg, were found. Anatomically, a 69% enlargement in right ventricular mass was observed, and this hypertrophic growth was characterized by a 78% thickening of the wall with no change in ventricular wall area, the latter calculated from the quotient of ventricular volume and wall thickness. Morphometric data showed a 44% increase in the capillary-to-myocyte ratio, a 66% augmentation of the total length of capillaries in the whole ventricle, and a 77% greater number of capillaries across the ventricular wall. Furthermore, these indexes of neogenesis of capillary units were associated with a more than three fold increase in the numerical density of mast cell profiles in the myocardium. In conclusion, capillary proliferation occurs in the adult rat heart, and this process appears to be coupled with mast cell hyperplasia.

Animals↗
PubMed1989

Capillary growth in anemia-induced ventricular wall remodeling in the rat heart.

To determine whether anemia-induced cardiac hypertrophy affects ventricular size and shape and the component structures of the capillary network of the left and right ventricles, young male rats were fed an iron- and copper-deficient diet for 7 weeks. By that time, blood hemoglobin content fell to 5 +/- 1 g/dl, and packed cell volume fell to 18 +/- 3%. To further characterize the implications of anemia, red blood cell number, hemoglobin corpuscular content, systemic arterial pressure, heart rate, and blood viscosity were measured. Moreover, the changes in ventricular weights were analyzed in terms of the alterations in ventricular wall area and ventricular wall thickness to establish the impact of the elevation in load associated with a high cardiac output state on ventricular remodeling. The quantitative properties of the capillary circulation were also examined biventricularly by low power electron microscopic morphometry to evaluate the adaptive growth potential of the coronary microcirculation in this form of cardiac hypertrophy. Anemia was found to interfere with the production of red blood cells and their mean corpuscular hemoglobin content and resulted in a 40% reduction in blood viscosity and a 12% and 27% decrease in systolic and diastolic blood pressure, respectively. The changes in heart rate were not statistically significant. In comparison with control animals, heart weight increased by 50%, but the enlargement in right ventricular mass (65%) was greater than that of the left ventricle (47%). Ventricular hypertrophy occurred with increases in wall area and wall thickness although the former increased consistently more than the latter in either ventricle. Tissue growth was accompanied by a 60% lengthening of the capillary network, which in combination with an increase in capillary diameter resulted in a 65% and 34% expansion in capillary luminal volume and 56% and 20% larger luminal surface density in the left and right sides of the heart, respectively. In conclusion, hypochromic microcytic anemia leads to eccentric ventricular hypertrophy with a significant amount of capillary proliferation that may tend to protect the myocardium from the increased potential for ischemic injury.

Adaptation, Physiological↗
PubMed1989

[Our ultrasonic experience in the diagnosis of traumatic lesions of the liver and spleen].

The authors on the basis of their series evaluate the accuracy of ultrasonography (US) in the diagnosis of intraperitoneal as well as hepatic and splenic intraparenchymal blood collections. Because of its reliability, lack of contraindications, feasibility at the patient's bed, easy remaking, US examination is the first choice approach to the patient with blunt abdominal trauma.

Abdominal Injuries↗
PubMed1989

[Validity of some electrocardiographic criteria in left ventricular hypertrophy].

The aim of the study was the assessment of the sensitivity, specificity and accuracy of some ECG criteria of left ventricular hypertrophy (LVH). Left ventricular mass (LVM) measured on the M-mode echogram of the left ventricle was the reference standard. Ninety-four (94) unselected, consecutive clinical patients (34 women, 60 men, average age 47 years) underwent in the same day, ECG and echocardiogram. Exclusion criteria were the presence of ischemic heart disease, atrial fibrillation and Wolff-Parkinson-White syndrome. The ECG tracings were interpreted independently by 2 investigators following 5 independent criteria of LVH: 1) Sokolow-Lyon voltage criterion (SL); 2) a modified Romhilt-Estes point score (REM); 3) left atrial abnormality (LAA); 4) left ventricular strain; 5) a new voltage criterion RaVL + SV3 corrected by sex and age. The left ventricular M-mode echograms were recorded using a left parasternal approach and were interpreted independently by 2 investigators. LVM was measured using the "Penn convention" and taking the R wave peak as end-diastole. The prevalence of LVH (= LVM 215 g) in the study population was 47%. The following results were achieved (sensitivity, specificity, accuracy): SL: 68.2%, 84%, 76.6%; REM: 63.6%, 90%, 77.7%: LAA: 36.4%, 84%, 61.7%; strain 52.3%, 72%, 62.8%; RaVL + SV3: 54.5%, 82%, 69.1%. Our data suggest: 1) the high sensitivity, specificity and accuracy of Romhilt-Estes point score are confirmed; 2) the sensitivity of Sokolow-Lyon voltage criterion is reevaluated; 3) the most sensitive morphological criterion seems to be the left ventricular strain; 4) a new voltage criterion could be useful.

Adolescent↗
PubMed1989

Morphometric analysis of coronary capillaries during physiologic myocardial growth and induced cardiac hypertrophy: a review.

The quantitative structural properties of the ventricular myocardium with respect to its capillary concentration and distribution have been measured morphometrically during postnatal physiologic growth and later in life in the rat, and compared with those accompanying an increased load in the adult heart to determine whether induced cardiac hypertrophy is a pathologic condition or a form of accelerated myocardial growth. The following morphometric parameters of the capillary microvasculature were examined: 1. Capillary luminal volume density; 2. Capillary luminal surface density; and 3. The average diffusion distance for oxygen. The expansion of the ventricular myocardium during maturation shows a remarkable degree of well balanced compensatory response, because the capillary microvasculature and myocytes grow in proportion to the increase in cardiac mass. In older rats parenchymal cells increase more than the capillary network resulting in a reduction of the oxygenation potential of the tissue and local ischemic damage. Cardiac hypertrophy produced by pressure overload, volume overload and by a combination of both may also show alterations affecting capillary luminal volume and surface densities and the path length for oxygen molecular transport, which indicate an inadequate growth adaption of the component structures responsible for tissue oxygenation. In conclusion, myocardial enlargement that develops with age or as a result of an increased work load on the heart may lead to a conditioned state of the myocardium that can be expected to increase its vulnerability to ischemia as in pathologic cardiac hypertrophy.

Aging↗
PubMed1989

The expression of functional IL-2 receptor on activated macrophages depends on the stimulus applied.

Human peripheral blood monocytes (Mo) synthesize prostaglandin E2 (PGE2) when activated with lipopolysaccharide (LPS). This production is strongly enhanced by the addition of supernatant from phytohaemagglutinin (PHA)-activated T cells. To evaluate the factor(s) responsible for this enhancement we studied the effect of several cytokines on the PGE2 metabolism. Recombinant interleukin-1 (IL-1) or recombinant IL-2 strongly enhanced PGE2 synthesis in LPS-stimulated Mo cultures, whereas recombinant interferon-gamma (IFN-gamma) partially inhibited its production. To see whether the effect of IL-2 on Mo was due to the presence of IL-2 receptor (IL-2R) on the cell surface, flow cytometric analysis and electron microscopy were used to investigate IL-2R expression in unstimulated and stimulated Mo. Stimulated, but not resting, Mo displayed the p55 IL-2R chain on their cellular surface and associated with the polyribosomes of the rough endoplasmic reticulum in the cytoplasm. This finding strongly suggested that the p55 chain of the IL-2R was synthesized by activated Mo. To confirm this result, 125I-labelled IL-2 was bound under high- and low-affinity conditions and cross-linked to Mo cultured in the presence of LPS, IFN-gamma or IL-1. The cross-linked 125I-IL-2/IL-2R complexes were analysed by SDS-PAGE. Mo cultured with LPS, IFN-gamma and IL-1 expressed the p55 protein detected by low-affinity cross-linking, whereas only LPS-stimulated Mo displayed a barely detectable band with an apparent MW of 70,000 under high-affinity binding conditions. In addition, stimulated Mo were found capable of producing the soluble form of IL-2R. Finally, LPS-activated Mo only responded to the addition of IL-2 by an increase in PGE2 production, suggesting that the function of IL-2R on activated Mo is linked to the stimulus applied.

Biological Factors↗
PubMed1989

The role of arachidonic acid metabolite PGE2 on T cell proliferative response.

We have examined the role of cyclooxygenase and lipooxygenase-derived metabolites of arachidonic acid (AA) during T cell activation. One of the major products of cyclooxygenase activity is prostaglandin E2 (PGE2). As is known, macrophages (Mo) are the main PGE2 producer cells among the peripheral blood mononuclear cells (PBL) and can be induced to release PGE2 during T cell activation. On culturing PBL with T cell mitogens such as phytohemagglutinin (PHA) or monoclonal antibody OKT3, the levels of PGE2 produced by Mo were positively correlated with the entity of the T cell mitogenic signal. During T cell activation, subcellular factors able to provide positive or negative signals on the Mo PGE2 production are released in culture. We observed that recombinant IL2 strongly enhanced PGE2 synthesis in lipopolysaccharide (LPS) stimulated Mo culture, while recombinant interferon gamma (IFN-gamma) partially inhibited its production. Moreover, purified IL1 induced PGE2 synthesis in resting Mo and increased its production when Mo were activated by LPS. The PGE2 released during T cell activation seems to have no effect on T cell mitogenesis, since the addition of cyclooxygenase inhibitors did not influence the proliferative response of mitogen stimulated T cells. However, the addition of PGE2 to OKT3 stimulated PBL at the beginning of the culture period inhibited the proliferative response in a dose-dependent manner. Its addition had no effect on PHA-stimulated PBL cultures. The PGE2-dependent inhibition of OKT3-induced T cell proliferation declined progressively from about 50-10% as the addition of PGE2 was delayed from 0 to 24 hr.(ABSTRACT TRUNCATED AT 250 WORDS)

Biological Factors↗
PubMed1989

Angulated transverse tomographic sections to measure cardiac dimensions by magnetic resonance imaging: a comparison with 2D-echocardiography.

Magnetic resonance imaging (MRI) has shown low accuracy in measuring cardiac dimensions in normal subjects, when transverse tomographic sections are used in comparison with 2D-echocardiography. The rationale of this study was to compare cardiac dimensions in 19 volunteers based on angulated (30 degrees caudo-cranial) transverse tomographic sections both in MRI and 2D-echo. Since the planes investigated by both techniques are superimposable, highly significant correlated Ao, LA, IVS, LW, LV, and RV dimensions are observed. Standardized MRI tomography permits reduction of total examination time and assures repeatability. Thus, using the method reported here, cardiac dimensions in humans might be obtained accurately by MRI.

Adult↗
PubMed1988

Cellular basis of wall remodeling in long-term pressure overload-induced right ventricular hypertrophy in rats.

To determine the effects of long-term pressure overload on the structural mechanisms implicated in wall remodeling of the right ventricle, a mild pulmonary artery banding was applied to rats approximately 2 months old, and the animals were killed 150 days later. The surgical procedure resulted in a 60% reduction in the cross-sectional area of the constricted vessel and a 52% increase in the weight of the right ventricle. The hypertrophic myocardial response was associated with an elevation in right ventricular systolic pressure (from 33 +/- 11 mm Hg to 71 +/- 12 mm Hg), right ventricular end-diastolic pressure (from 3 +/- 1 mm Hg to 10 +/- 3 mm Hg), and central venous pressure (from 2 +/- 0.2 mm Hg to 10 +/- 3 mm Hg). The 76% increase in wall thickness after pulmonary artery stenosis was the result of a 24% lateral expansion of cardiac muscle cells and a 44% increase in the number of myocytes across the ventricular wall. The intermyocyte distance was also increased by 22%. These cellular adaptations occurred with no alterations in total myocyte length, average sarcomere length, and volume composition of the myocardium. Ventricular wall area was decreased by 14%, which suggests a small reduction in chamber volume. Myocyte growth was accompanied by proportional expansions of mitochondrial and myofibrillar components, so that the ratio of mitochondria to myofibrils in the cytoplasm remained essentially constant. In conclusion, ventricular remodeling in this model of chronic pressure hypertrophy is characterized by increases in cellular diameter and number that would both tend to decrease the magnitude of systolic and diastolic stresses on a per cell basis and thus improve the myocardial response to a prolonged and sustained mechanical load.

Animals↗
PubMed1988

[MacLeod's syndrome. Observations on 6 cases].

Mac Leod's syndrome is a rarely diagnosed disease; that is why an accurate differential diagnosis is needed by means of radiological imaging. This paper is aimed at discussing the differential diagnosis, with a special emphasis on the pathogenesis of the syndrome. The phenomenon of air trapping in absence of central bronchial lesions is a typical radiographic finding. Chest X-ray is performed in both inspiration and expiration. Posterior oblique tomography at 55 degrees of the affected side is also performed. Diffuse bronchiolitis obliterans in infancy or early childhood is a widely accepted pathogenetic pattern. Pulmonary hypoventilation causes vasoconstriction and underdevelopment of pulmonary vessels, that are reduced in caliber. Differential diagnosis includes all the diseases resulting in pulmonary hyperlucency, i.e. pulmonary and pleural alterations, and skeletal anomalies.

Adult↗
PubMed1987

First-trimester prenatal diagnosis of Sanfilippo C disease.

At 10 weeks' gestation, chorionic villus biopsy was obtained from a woman at risk for Sanfilippo type C disease. Acetyl-CoA: alpha-glucosaminide N-acetyltransferase activity was markedly deficient. The pregnancy was terminated at 12 weeks' gestation and follow-up study on fetal fibroblasts confirmed the diagnosis.

Adult↗
PubMed1987

Increased incidence of isoproterenol-induced ventricular fibrillation in aging rats.

Prolonged beta-adrenergic stimulation obtained by subcutaneous injection of isoproterenol in unanesthetized, unrestrained rats elicited ventricular fibrillation in approximately 80% of animals at 10-12 months of age. Ventricular fibrillation failed to occur in 1-month-old rats and involved only 12% of rats at 2 months. Senescence appeared not to increase the frequency of ventricular fibrillation since a similar incidence was seen in rats at 10-12 and 19-21 months. In all instances, ventricular fibrillation was preceded by ECG changes consistent with acute subendocardial ischemia. To evaluate whether acute beta-adrenergic stimulation elicits comparable cardiovascular effects in animals of different age, a dose-response curve to intravenous injection of isoproterenol was performed in anesthetized rats. Changes in heart rate, systemic arterial pressure, left ventricular pressure, and dP/dt were not different among animal groups. It was concluded that the arrhythmogenic potential of isoproterenol may not be related to differences in cardiac beta-receptor sensitivity with age as suggested by the comparable changes in the inotropic and chronotropic actions of isoproterenol in the animal groups studied.

Aging↗