Regression of cholesterol induced venous plaques after cholesterol withdrawal in rabbits.

Rabbits receiving a dietary cholesterol supplement of 0.5% develop atheromatous plaques in the systemic arteries, the pulmonary artery, the pulmonary veins and the venous cavities of the plexus pampiniformis in the funiculus spermaticus. Six months after the withdrawal of the cholesterol supplement the arterial lesions are still present, and show a fibrous transformation.

Cell composition, replication, and apoptosis in atherosclerotic plaques after 6 months of cholesterol withdrawal.

Unstable human atherosclerotic plaques are characterized by a thin fibrous cap that contains few smooth muscle cells (SMCs) and numerous foam cells of macrophagic origin. Apoptosis of SMCs in the fibrous cap could destabilize the plaque and promote plaque rupture. In an experimental approach, we have studied apoptotic cell death and related proteins in atherosclerotic plaques of cholesterol-fed rabbits and examined the effects of cholesterol withdrawal.

Localization of extracellular superoxide dismutase in rat lung: neutrophils and macrophages as carriers of the enzyme.

Immunohistochemistry (IHC) and in situ hybridization (ISH) was used to localize extracellular superoxide dismutase (EC-SOD) and its mRNA in rat lung before and after a lipopolysaccharide (LPS)- and hyperoxia-induced inflammation. In control rats, EC-SOD mRNA was synthesized in macrophages and in cells of the arterial vessel walls and the alveolar septa. The EC-SOD protein was mainly localized in plasma and on the apical side of the epithelial cells located near bronchus-associated lymphoid tissue (BALT).

Possible mechanisms of collar-induced intimal thickening.

The positioning of a soft silicone collar around the rabbit carotid artery induces intimal thickening. We investigated to which extent occlusion of the vasa vasorum, damage of the perivascular nerve network, and/or changes in blood flow velocity contribute to intimal thickening. To this end, collars with different bores (diameter of inlet and outlet) were positioned around the carotid artery of male rabbits for 14 days.

Centrolobular liver fibrosis in the hypercholesterolemic rabbit.

During a study on the development of atheromatous lesions in rabbits fed a diet with a low or high cholesterol supplement, we found a moderate to pronounced centrolobular liver fibrosis. This fibrosis developed in three stages. Early after supplementation of cholesterol, we observed increased immunoreactivity of collagen types I, III, and IV, and fibronectin, around central veins and in adjacent sinusoids.

Destruction of lacis cells of the juxtaglomerular apparatus in the hypercholesterolemic rabbit.

During a study of experimentally induced atheromatosis in hypercholesterolemic rabbits we found a heavy infiltration of the lacis cell field (G field) by lipids in the kidney. A systematic study was done in 12 rabbits receiving a dietary cholesterol supplement of 0.3% for 26 weeks and in 8 animals receiving a supplement of 2% for 8 weeks.

The influence of collapse of the lung parenchyma on the morphology of pulmonary blood vessels in the rat.

During a search for resident subendothelial smooth muscle cells in pulmonary vessels of the rat we found that in expanded lungs the muscular pads in the veins, considered by some authors as sphincters, were hardly visible whereas in collapsed lungs they were very conspicuous. In a separate study intended to quantify the degree of collapse or expansion the left lung was examined in 5 rats with a collapsed and in 5 rats with an expanded lung: the expansion was produced by filling the airways by gravity with Methacarn fixative. The degree of expansion was determined by morphometry measuring the volume density of the tissue fraction of the pulmonary parenchyma in the microscopic sections: in the expanded lung the mean value was 8.

Sephadex induced granulomatous reaction in rats.

Granuloma formation in the rat lung after single or repeated i.v. injections, intratracheal instillation and intradermal implantation of Sephadex beads was studied over a time period from 3 h to 3 mo.

Hyperplasia, hypertrophy, and phenotypic alterations in the distal nephron after acute proximal tubular injury in the rat.

Background: Little is known about the impact of acute proximal tubular injury and dysfunction on the distal nephron.

Experimental Design: Selective necrosis of the kidney proximal convoluted tubule (PCT) was induced in rats by subcutaneous injection of the aminoglycoside gentamicin during 2 days. Damage and repair were measured until complete morphologic recovery after 10 days.

The relationship between pre-existing subendothelial smooth muscle cell accumulations and foam cell lesions in cholesterol-fed rabbits.

We investigated whether pre-existing subendothelial smooth muscle cell (SMC) accumulations in cholesterol-fed rabbits are transformed into foam cell plaques. Twenty-four rabbits received a standard diet supplemented with 2% cholesterol for 4 or 8 weeks. Six rabbits received a supplement of 0.

Ultrastructural demonstration of type IV collagen deposits in periductal elastosis in breast cancer.

In a previous study we demonstrated at light microscopical level the presence of variable amounts of type IV collagen in the areas of periductal and interstitial elastosis in breast cancer. The present work was directed towards a further study by immunoelectron microscopy of the distribution of type IV collagen in the areas of periductal elastosis. The semithin sections showed a distinct immunoreactivity of all basement membranes for type IV collagen but no staining of the interstitial stroma.

Longitudinally oriented smooth muscle cells in rabbit arteries.

Intima formation in vessels, spontaneous or experimentally induced, is generally characterized by the presence of longitudinally oriented smooth muscle cells (LSMC). During an experiment of neo-intima induction in carotid arteries in rabbits, by application of a non-constrictive silastic cuff, a study was performed to investigate the presence of LSMC in the systemic and pulmonary circulations, in both elastic and muscular arteries. Three patterns could be distinguished: intimal cushions in muscular arteries, single or small groups of LSMC in the intima in elastic and larger muscular arteries, and intra-medially located layers or columns of LSMC in the aorta, the pulmonary artery, at the bifurcation of the aorta and around orifices of branches.

Ileal intussusception due to invagination of Meckel's diverticulum.

A middle-aged patient is reported who came to laparotomy after a six months period of abdominal complaints. Extensive investigations couldn't explain his symptoms. At laparotomy he was found to have an ileal intussusception due to an invaginated Meckel's diverticulum.

Quantitative relationships between body weight, kidney weight and nephron size in mongrel dogs.

Mammalian species of large stature have larger kidneys with larger nephrons than smaller animals, although this relationship is not linear. In order to investigate whether in animals of different sizes within the same species similar differences exist, a study in mongrel dogs was undertaken. In animals weighing between 9 and 42 kg with kidney weights from 25 to 79 g the area and perimeter of the glomeruli and the cortical width were measured.

A standardized surgical technique to obtain a stable and reproducible chronic renal failure model in dogs.

The remnant kidney, a model of chronic renal failure in animals, can be obtained by two techniques: either surgical removal of tissue of one kidney, combined with contralateral nephrectomy or inducing necrosis of kidney tissue by ligation of branches of the renal artery of one kidney combined with contralateral nephrectomy. In the literature, most reports concern the ligation technique. The technique is safe and simple but the results in dogs are unpredictable.

Effect of ageing and malnutrition on rat myocardium. II. The microvasculature.

The modulating effects of ageing and malnutrition on rat myocardium were studied morphometrically with respect to the microvasculature. An increase in capillary density together with a decrease in capillary lumen cross-sectional area was noted during starvation. The important changes seen in the myocyte T-system were paralleled by a decreased diffusion distance for oxygen from the capillary lumen to the mitochondrion.

Effect of ageing and malnutrition on rat myocardium. I. The myocyte.

The effects of ageing and starvation on the rat myocardium were studied by morphometric methods. Since cardiac muscle is a tissue with a high level of anisotropy, methods based on the concept of vertical planes were used to describe quantitative alterations in the rat myocyte both at the cellular and ultrastructural level. During starvation rapid and important changes were noted, particularly in the transverse dimension of cells and organelles.

Stromal populations and fibrosis in human long-term bone marrow cultures.

An immunofluorescence study of the adherent layer of human long-term bone marrow cultures (HLTBMC) revealed the following surface markers on the different stromal cell populations: stromal fibroblastic cells CD10+, FIB86.3+, CD13+, CD71+; adipocytes CD10+, FIB86.3-, CD13+, CD71-/+; and macrophages CD10-/+, FIB86.

Ridogrel prevents the thromboxane-mediated pressor response and oedema induced by hydrogen peroxide in isolated rabbit lungs.

Perfusion of isolated rabbit lungs with hydrogen peroxide (H2O2, 3 x 10(-5) M) raised the overflow of thromboxane B2 (TXB2) and the perfusion pressure. H2O2 induced oedema formation and endothelial distress, as evidenced by an increased production of 6-oxo-prostaglandin F1 alpha (6-oxo-PGF1 alpha). Endothelial cell death did not occur since there was no release of lactate dehydrogenase.

Neointima formation impairs endothelial muscarinic receptors while enhancing prostacyclin-mediated responses in the rabbit carotid artery.

The purpose of this study was to determine whether the generation of a neointima, an early step in the development of atherosclerosis, affects endothelium-dependent or -independent vasodilation. The neointima was induced, within 7 days, by positioning a nonocclusive silicone collar around one carotid artery in rabbits. After 1, 2, 7, or 14 days segments were cut from the collar-surrounded region of this artery as well as from the sham-operated contralateral artery and were used for isometric tension recording or for bioassay of nitric oxide (NO).

Comparison of cell growth in different parts of breast cancers.

This study was performed to answer the question: which parts of breast cancers are active in terms of proliferation as measured by the Ki-67 antibody and in terms of cell division as measured by the mitotic index. Forty-six breast samples were studied, including 34 breast cancers and 12 benign conditions. The intraductal component of infiltrating breast cancers showed a significantly lower proliferation index than the infiltrating component.

A study of the so-called neurotization of nevi.

Fourteen nevi with neuroid zones were examined and compared with nine nevi without neuroid structures. At light microscopic level, nevus cells from the neuroid nevi and the control nevi show the same staining pattern with polyclonal antibodies against S-100 protein. Around the cells of the neuroid zones is a more intensive immunoreactivity with monoclonal antibodies against laminin and collagen type IV than around the nevus cells in the upper dermis and the nevus cells in the control nevi.

Heat-stable alkaline phosphatase as a marker for human and monkey type-I pneumocytes.

The expression of the heat-stable isoenzyme of alkaline phosphatase in the human and monkey (Macaca mulatta, M. fascicularis) lung was investigated at the light- and electron-microscopic level, using cytochemical techniques and immunocytochemical procedures based on monoclonal and polyclonal antibodies against human term-placental alkaline phosphatase. Both in man and monkey, the enzyme was present in type-I pneumocytes.

Intrahepatic lymphatics in the human fetus.

Graphic reconstruction of dilated intrahepatic lymphatics in a 36 week old fetus displayed an anastomosing network of channels with intraluminal valves. Examination of the liver in 42 fetuses between the gestational age of 15 to 40 weeks showed that lymph vessels were visible as early as the 15th week. The detection of intrahepatic lymphatics was not related to the weight of the liver, the underlying cause of death, gender, or congenital anomalies.