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-/+, FIB86.3+, CD13+, CD71-/+, CD14+, CD33+, CD25+, HLA-DR+, CD4+, CD19+, CD45+. The markers of the stromal fibroblastic cells in HLTBMC were similar to those of twice-passaged fibroblasts not only from bone marrow and spleen, but also from a hemopoietic non-supportive organ such as the skin. Some of the cultured human umbilical vein endothelial cells used as controls were found to be CD25+, demonstrating for the first time the interleukin-2 receptor p55 chain on normal non-hemopoietic cells. The stromal fibroblastic cells are overrepresented compared to the small non-macrophage hemopoietic cell population in the adherent layer of HLTBMC. In addition, silver staining revealed an increased reticulin content in most of the HLTBMC. An excessive growth of stromal fibroblastic cells and an excessive deposition of their product, the reticulin fibers, are the hallmark of myelofibrosis. The finding of equivalent observations in HLTBMC suggests that the hitherto unexplained, premature quenching of hemopoiesis in HLTBMC might at least partly be due to mechanisms similar to those operating in myelofibrosis in vivo.

Purpura fulminans in pneumococcal sepsis.

Two cases of pneumococcal sepsis in splenectomized patients were complicated by purpura fulminans. In addition, acute renal failure developed in both patients, and myolysis in one. Immunological findings in the patient with myolysis suggest a possible role of pneumococcal antigen-containing circulating immune complexes in the pathogenesis of these complications.

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). ISH did not reveal major changes in the distribution of EC-SOD mRNA upon induction of inflammation. In contrast, IHC demonstrated a progressive staining of the epithelium of the larger bronchi for the protein. Neutrophils and macrophages invading the lung showed an intensive staining for the EC-SOD protein concomitantly with a decrease of the enzyme in the plasma. Twenty-four hours after LPS stimulation only a spotty positivity remained on neutrophils in and between the alveolar spaces. In the bronchoalveolar lavage fluid (BALF), only macrophages showed a strong positivity for EC-SOD mRNA while the protein was detected in macrophages and neutrophils. Exposure to hyperoxia did not affect the distribution of EC-SOD mRNA and protein. The presented data demonstrated that in lung tissue the EC-SOD enzyme may have a protective function for activated macrophages, neutrophils, and lympoid tissue-associated epithelial cells.

The presence of a type IV collagen skeleton associated with periductal elastosis in breast cancer.

Using serial sections of frozen and AFA-fixed tissues from 34 breast cancers, we studied the presence of basement membrane material in the areas of elastosis. Various amounts of type IV collagen but not of laminin were demonstrated in areas of periductal elastosis. In some tumors, type IV collagen accumulated beneath the basement membrane. Periductal elastosis in areas of extensive fibrosis showed focal type IV collagen immunoreactivity, indicating remnants of ducts. Interstitial elastosis corresponded with weak type IV collagen reactivity. Each tumor showed type IV collagen immunostaining of the elastotic areas, with various degrees of intensity. Negative crossreactivity of the type IV collagen antibody with elastin was verified in skin biopsies with solar elastosis. Pre-incubation of the antibody with large amounts of elastin demonstrated an identical immunoreactivity. The specificity of the antibody was confirmed by ELISA and by Western blot analysis. To explain the periductal elastosis, we propose the following hypothesis. Excessive production of basement membrane material by the epithelial cells of the ducts leads to formation of a type IV collagen skeleton. This skeleton can act as the matrix for a secondary deposition of elastic material.

Nonlymphoid hematopoietic malignant disease of the lymph nodes.

The extension of myeloproliferative malignant tumors to lymph nodes was studied in seven excision biopsies and 27 autopsies in which lymph nodes were obtained from all nodal regions. We observed the proliferation of poorly, partially, and well differentiated neoplastic cells with a predominance of immature cells of the granulocytic series and fewer cells of the erythroid and megakaryocytic cells lines. Disturbances of the lymph node architecture consisted of invasion by abnormal cells of the trabecular stroma, disrupting the reticulin mesh and extending toward the pericapsular area. In the lymph node a loose network of thin and thick fibers replaced the original framework. Generalized lymph node involvement at autopsy showed preservation of the architecture, both in cases with total replacement of the lymphoid population by abnormal cells and in cases with involvement by single cells or small groups of cells. Partial involvement occurred chiefly in the medullary zone, probably the result of hematogenous dissemination from the vascular plexus in medullary cords. Further abnormal cell development was linked to trabecular infiltration. The extensive involvement seen at autopsy took place by lymphatic dissemination. In lymph nodes studied at autopsy an abnormal immunoblastic reaction was observed. At first these abnormal cells were suspected of representing the myeloproliferative malignant disease, but the application of special staining techniques revealed their polyclonal cytoplasmic immunoglobulins. The chloroacetate esterase stain and the immunohistochemical stains for muramidase and hemoglobulin were especially useful in demonstrating that myeloproliferative diseases develop in the environment found in lymph nodes.

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 0.3% cholesterol for 35 weeks. The aorta and other systemic and pulmonary vessels were studied by immunohistochemistry for smooth muscle cells SMC (alpha-SMC actin), macrophages (RAM11), cell replication (proliferating cell nuclear antigen) and endothelial cells (von Willebrand factor; vWF). Initially the foam cell plaques were composed exclusively of foam cells of macrophage origin (MFC). In more advanced lesions SMC and collagen fibres were also present, leading to a fibrous transformation of the plaque. Cell replication was mainly located in the MFC. The endothelial cells covering the plaques showed an increased immunoreactivity for vWF which was also deposited in the interstitium between the FC. Pre-existing subendothelial SMC did not transform into FC. The newly formed FC plaques remained clearly separated from the pre-existing subendothelial SMC. The development of the plaques can be attributed not only to monocyte recruitment but also to macrophage multiplication.

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. The thromboxane A2 (TXA2)-synthase inhibitor/receptor antagonist ridogrel (R68070) further enhanced 6-oxo-PGF1 alpha output, while inhibiting TXB2 release. Ridogrel prevented the rise in pulmonary artery pressure and oedema formation. These data indicate that TXA2 is probably involved in the acute pulmonary pressor response and concomitant oedema formation induced by H2O2. In order to assess the functional activity of the pulmonary endothelium, the uptake of 5-hydroxytryptamine (5-HT) was measured before and 15 min after exposure to H2O2. As the H2O2-induced effects were not associated with any change in the uptake of 5-hydroxytryptamine (5-HT), we conclude that the endothelial injury was reversible or that the 5-HT uptake was not sensitive enough to evaluate the integrity of the pulmonary endothelium during oxidant-induced injury.

Peritoneal dialysis in acute renal failure due to cholesterol embolization: two cases of recovery of renal function and extended survival.

Recovery of renal function and extended survival after acute renal failure due to cholesterol embolization are possible, as demonstrated by the case history of two patients. Both were treated with peritoneal dialysis during their acute insult and had a serum creatinine of 1.7 mg/100 ml and 2.4 mg/100 ml, respectively, 12 and 60 months after diagnosis. Peritoneal dialysis is the preferred procedure for the replacement of renal function in these patients since it achieves good control of blood pressure and volume overload and avoids the need for vascular access and heparin administration.

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. Corresponding ultrathin sections demonstrated a broad basement membrane with immunoreactivity for type IV collagen at its outer side. Many punctiform deposits of type IV collagen were observed in the areas of periductal elastosis but not around normal ducts or vessels. Recently the role of type IV collagen as a structural component on anchoring plaques between the basement membrane and the underlying stroma in the dermis has been emphasized. The results of this study demonstrate the presence of type IV collagen deposits below a thickened basement membrane in breast cancer.

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. Standard histology, immunohistochemistry for a-smooth muscle cell actin and with the macrophage specific antibody RAM 11, and transmission electron microscopy were performed. In the low cholesterol, long duration group, 90% of the G fields were involved. The lipid accumulation was mainly extracellular. The lacis cells contained moderate numbers of medium sized lipid vacuoles and showed signs of cytoplasmic damage leading to disintegration. The mesangial cells contained few dipid droplets and the matrix was normal. The arterioles were not involved. The lesion suggests an impairment of the clearance of lipids, leading to interstitial accumulation and cellular damage.

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. Macrophages were identified with the mAB ED1, vascular smooth muscle cells with an mAB against alpha SMC-actin, endothelial cells with a polyclonal AB against factor VIII and cyclic activity with an mAB against PCNA. The morphology and the time course of the development of the granulomas is identical in the different experimental conditions. The macrophages form the bulk of the cellular infiltrates, giant cells appear after 24 h. Cyclic activity is early and marked in the interstitially located macrophages, it is delayed and slight around the beads, suggesting a biphasic pattern. The macrophage reaction is markedly enhanced after a second i.v. injection, indicating the development of a hypersensitivity state. Numerous eosinophils are located in the interstitium, but only few are in direct contact with the beads. Their number doesn't increase after a second i.v. injection. Intradermal implantations show only macrophages and lymphocytes. A special feature is the disappearance of the arterial wall around the beads resulting in extrusion without haemorrhages or thromboses.

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. This study is the first report of the total regression of the lesions in the particular venous localizations of the lungs and the plexus pampiniformis. The level of intraluminal pressure is discussed as the possible mechanism responsible for the diverging vascular reactivity.

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.

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. These events are confronted with other collected literature reports. Symptomatology and treatment are discussed.