Location and identification of the collagen found in the 14.5-d rat embryo visceral yolk sac

The collagens associated with 14.5-d rat visceral yolk sacs were localized and identified by a variety of procedures. Morphological examination showed that both the visceral epithelium and mesothelium rested upon thin basement membranes, whereas the majority of the extracellular matrix consisted of a stroma containing occasional cells and abundant banded fibrils. Immunohistochemistry at the electron microscope level showed that the basement membranes specifically cross-reacted with antibodies directed against mouse basement membrane components, whereas the stroma specifically cross-reacted with antibodies directed against rat type I collagen. Extractions of acellular visceral yolk sacs and subsequent analyses showed that type I collagen components were prevalent. Furthermore, in vitro biosynthetic studies showed only the presence of type I procollagen components (or their conversion products) and alpha-fetoprotein. These findings, taken together with our previous studies on the 14.5-d rat parietal yolk sac, provide us with protein markers for studying the origin of cells in rat parietovisceral yolk sac carcinomas.

Human dendritic cells. Enrichment and characterization from peripheral blood

Previous studies demonstrated that lymphoid tissues of mice and rats contain small numbers (less than 1 percent of nucleated cells) of dendritic cells (DC) with special cytologic, surface, and functional properties. We show here that similar DC represent 0.1-0.5 percent of human peripheral blood mononuclear cells. DC can be enriched to 20-60 percent purity by a multistep procedure analogous to that used in mice. Adherent peripheral blood mononuclear cells are cultured overnight, and the released cells are depleted of monocytes and B cells by readherence to plastic, rosetting with erythrocytes coated with anti-human IgG, and centrifugation in dense albumin columns. Enriched DC have similar cytologic features to rodent DC by light and electron microscopy. DC express HLA, and HLA-DR and the leukocyte-common antigens. They lack phagocytic capacity, receptors for antibody-coated and neuraminidase-treated erythrocytes, surface and intracellular Ig, esterase, peroxidase, and azurophilic granules. DC do not react with several monoclonal antibodies directed to phagocytes (OKM 1, "mac-1," 63D3, and 61D3) and T cells (OKT 3, 6, 8). Unlike the mouse, human DC express complement receptors. When maintained in culture for 4 d, human DC did not give rise to either B cells or monocytes. Therefore, DC identified by cytologic criteria are distinct from other leukocytes. Enriched populations of DC have been compared to fractions enriched in monocytes, B cells, and T cells in three functional assays: stimulation of the primary allogeneic mixed leukocyte reaction, stimulation of the primary syngeneic MLR, and accessory function for the proliferation of periodate- modified T cells. In each case, the DC fraction was 10-fold or more active than other cell fractions. We conclude that DC circulate in man, and represent the principal cell type required for the initiation of several immune responses.

Rainbow trout macrophages in vitro: morphology and phagocytic activity

The properties of macrophages from the pronephros of Rainbow trout (Salmo gairdneri Richardson) were studied in vitro. We found that phagocytes obtained from the pronephros constitute a non-homogeneous cell population. Three populations with different adherence properties were examined with special emphasis on morphology and phagocytic capacity. The differentiation of the three populations in culture was similar morphologically, and their phagocytic activity showed only small variations. The methods for cell separation and culture reported here are a useful tool for gaining better understanding of how Rainbow trout macrophages function in the immune response.

Nuclear alterations during lymphocyte transformation: relationship to the heterogeneous morphologic presentations of non-Hodgkin's lymphomas

A current hypothesis related to non-Hodgkin's lymphoma states that the wide variety of cytologic types in this disorder reflects morphologic alterations during different stages (G1, S, and G2) of the cell cycle involved in the blastogenic transformation of normal lymphocytes. In our investigations of biochemical and structural changes during lymphocyte transformation, we have used correlated stereologic morphometric analysis, assessment of chromatin organization, and autoradiography of human peripheral T-lymphocytes labeled with 3H-thymidine and stimulated with concanavalin A. These studies have confirmed that the characteristic increase in nuclear size and disaggregation of condensed chromatin masses precedes and is independent of DNA synthesis. Since the full range of morphologic alterations observed in lymphocyte transformation can occur in the G1 phase of this process, modifications to the above hypothesis are required. Assessment of the nuclear contour index following mitogen stimulation indicates that at least in this in vivo system, there is no cleaved or convoluted phase during the transformation of human peripheral T lymphocytes.

Role of activated macrophages in antibody-dependent lysis of tumor cells

Treatment of mice with Bacille Calmette-Guérin (BCG) or C parvum activates their peritoneal macrophages to release increased amounts of H2O2, and thereby to lyse extracellular tumor cells, in response to a pharmacologic agent, phorbol myristate acetate (PMA) (1-3). In the present study, the same bacterial vaccines activated peritoneal cells to become cytolytic to lymphoma cells sensitized with alloantiserum, in the absence of PMA. Resident peritoneal cells, or those elicited with thioglycollate broth, were ineffective, not only in PMA-induced lysis, but also in antibody-dependent lysis of tumor cells. The cytolytic effect of BCG peritoneal cells toward sensitized tumor cells appeared to be mediated mostly by macrophages. Cytotoxicity was immunologically specific, contact dependent, rapid, and efficient. Phagocytosis of intact tumor cells was not involved. Alloantiserum-dependent cytolysis was specifically blocked by the Fab fragment of a monoclonal antibody directed against the trypsin-resistant macrophage Fc receptor (FcR II). Thus, tumor cells coated with homologous immunoglobulin interact with FcR II on activated macrophages to trigger an extra-cellular cytolytic response.

[Osteomalacia due to vitamin D deficiency. Part two: Aetiology (author's transl)]

The mechanisms of vitamin D deficiency already described are triggered off by a variety of causes. Confinement indoors leads to defective photosynthesis and dietary restrictions to insufficient intake. Malabsorption results from digestive tract diseases: mainly adult coeliac disease, but also sequelae of gastrectomy, exocrine pancreatic insufficiency, chronic biliary obstruction and all other causes of steatorrhoea. Practically, osteomalacia of digestive origin usually results from multifactorial hypovitaminosis D. The same applies to primary or nutritional biliary cirrhosis, which frequently entails low vitamin D blood levels despite subnormal 25-hydroxylation. Osteomalacia is also found in renal osteodystrophy, where it is partly due to inhibition of 1,25-hydroxylase and subsequent deficiency of 1,25-dihydrocholecalciferol, though other, non vitaminic substances may also be involved. Two misleading forms of the disease must be borne in mind: one with renal tubular lsions, the other associated with functional pseudo-hypoparathyroidism. The aetiology of most cases of osteomalacia due to vitamin D deficiency can be elucidated by a few simple tests.

[Osteomalacia due to vitamin D deficiency. Part One: mechanisms (author's transl)]

Vitamin D deficiency is in most cases subclinical and can only be detected by blood vitamin assays or biochemical changes in phosphorus and calcium metabolism. Clinical and radiological osteomalacia is much less common. It is due to prolonged and profound hypovitaminaemia, which in turn depends upon a variety of factors, the main one being defective photosynthesis. Low vitamin D dietary intake apparently does not result in osteomalacia unless it is accompanied by insufficient exposure to sun. Malabsorption of cholecalciferol results from steatorrhoea of various origina. Disorders in hepatic 25-hydroxylation are due to drug enzymatic induction and seem to be unrelated to the state of the renal function. Disorders in renal 1,25-hydroxylation may be consecutive to reduced renal tissue, impaired stimulation, or inhibiton or even congenital lack of 1-alpha hydroxylase.

T- and B-cell-independent activation of syngeneic macrophages by murine sarcoma cells

Mouse peritoneal macrophages were achieved by cocultivation with syngeneic sarcoma cells. The tumor cells died progressively during the cocultivation, leaving highly activated marcophages. Because of great changes in macrophage morphology during the activation, special efforts were made to identify the activated cells as macrophages by their ability to phagocytose latex and to bind opsonized sheep red cells to C3 and Fc receptors and by indirect immunofluorescence with an antimacrophage antiserum. Activation was evaluated by morphology and incorporation of [14C]glucosamine. The activation was found to be independent of the presence of T-cells, B-cells, and immunoglobulin bound to tumor cell surfaces. This was shown by removal of T-cells from the system by treatment with anti-theta and complement and by use of nude mice as the macrophage source and for tumor maintenance. Similarly, B-cells were removed by treatment with anti-immunoglobulin and complement as well as adherence to anti-immunoglobulin-coated plastic dishes. Immunoglobulin bound to tumor cells was removed by trypsinization and by elution at low pH. Culture supernatants from tumor cells and cell-free tumor ascites fluid also induced some activation of the macrophages. This activation differed from the coculture activation in both the extent and kinetics of morphological changes and gave only a small increase in [14C]glucosamine incorporation.

[Transient osteoporosis of the hip in pregnancy. Report of three cases (author's transl)]

Three cases of transient osteoporosis of the hip in pregnant women are reported, and compared with 13 similar observations, published in world literature. The disease occurs during second half of pregnancy, revealed byrnotion hip pain, and slight limitation of mobility. On radiography, the femoral head and acetabulum are radiolucent and heterogenous. These modifications may be impressive but careful analysis of X rays rules out coxitis or malignant osteolysis. Major functional disturbance is common but the course of pregnancy and delivery is not impaired. Healing, without sequelae, occurs in a few months. Before delivery, attention should be paid to the fetal risk when prescribing X rays examinations or drug treatment. Pathogeny is unclear; the role of nerve or vein compression by the pregnant womb is discussed.

Insertion and turnover of macrophage plasma membrane proteins

The composition, insertion, and turnover of externally disposed proteins on the macrophage plasma membrane were analyzed. Cells labeled with [35S]methionine were incubated with the nonpermeant reagent trinitrobenzene sulfonic acid to introduce the trinitrophenyl moiety on free amino groups of externally oriented membrane proteins. The cells were then incubated with rabbit anti-dinitrophenyl IgG and the immune complexes formed with the trinitrophenyl-proteins were isolated from detergent lysates of the cells by using fixed Staphylococcus aureus as the immunoadsorbent. Proteins isolated by this method were analyzed by sodium dodecyl sulfate/polyacrylamide gel electrophoresis. The interval between the release of newly synthesized proteins from ribosomes and their appearance at the cell surface, where they became accessible to trinitrobenzene sulfonic acid, was studied in pulse-chase experiments. The "transit" time of four major membrane glycoproteins (48,000--310,000 Mr) ranged from 36 to 55 min and their appearance on the cell surface occurred in a relatively synchronous fashion. The turnover of most proteins of molecular weight above 50,000 was very slow (t1/2 greater than 80 hr) and was rather synchronous. Two exceptions were the 310,000 Mr protein, which was lost with a t1/2 = 21 hr, and a major glycoprotein (Mr 48,000), which exhibited more complex kinetics. Although the overall turnover of surface proteins was biphasic in nature, the rapid phase of protein loss was largely due to low molecular weight species.

Fc-receptor variants of a mouse macrophage cell line

Variants of the J774 mouse macrophage cell line that lack immunologically important membrane receptors were isolated. After mutagenesis, variants were selected in a metrizamide gradient that separated cells heavily rosetted with sheep erythrocytes (E) coated with rabbit anti-E IgG (EIgG) from poorly rosetted cells. Stable variants that exhibited altered binding were found with a frequency of <10(-7), and five clones were studied in detail. The variants failed to bind E opsonized with a monoclonal mouse IgG2b anti-E antibody but bound monomeric IgG2a normally when compared to the parental J774 line (K(a) 4 degrees C= approximately 1x10(8) M(-1); approximately 2x10(5) sites per cell). This demonstrates the independence of the receptor for mouse IgG2b complexes (FcRII) from the trypsin-sensitive receptor for mouse IgG2a monomer (FcRI). The variants bound an average of 10-15 EIgG per cell, compared to >20 per cell for J774. After trypsinization, three variants bound only three to five EIgG per cell; the J774 line was not affected by this treatment. Monomeric IgG2a could inhibit the binding of soluble rabbit IgG-antigen complexes to the variants but not to the parent line. Finally, E coated with IgM and complement (EIgMC) were bound poorly by all the variants, relative to the J774 parent. These results show that rabbit IgG complexes are bound by both FcRI and FcRII on mouse macrophages. The impairment of EIgMC rosetting in the variants suggests that the C3b receptor and FcRII are related.

Identification of a novel cell type in peripheral lymphoid organs of mice. V. Purification of spleen dendritic cells, new surface markers, and maintenance in vitro

Dendritic cells (DCs; 1) have been purified from mouse spleen in good yield. Spleen cell suspensions were floated on dense bovine plasma albumin (BPA) columns, and the low density fraction was adhered to glass (2). The adherent cells consisted of DCs and immature macrophages most of which eluted in a viable state from the culture dish after overnight incubation. The macrophages were then removed by selective rosetting with opsonized erythrocytes and recentrifugation on dense BPA. This protocol resulted in a purified DC fraction, containing 1--3 X 10(5) DCs/spleen, which was homogeneous and distinctive in its properties. All cells exhibited the phase contrast and transmission electron microscopy (EM) cytologic features that were previously described for freshly isolated adherent DCs. By scanning EM, most purified DCs exhibited a remarkable array of bulbous protrusions of varying length and shape, unlike any other lymphoid cell. All DCs expressed surface Ia and other major histocompatibility complex (MHC)-linked alloantigens. DCs, however, lacked surface Ig and T-cell antigens, and did not bind or interiorize opsonized erythrocytes. Purified DCs have been maintined in vitro for 3 days. Recovery of cultured purified cells was 70% or more of starting cell numbers. When [3H]uridine-tagged DCs were mixed with nonlabeled heterogeneous spleen cells, 70--80% of the labeled DCs were recovered as viable cells 2--3 days later. Purified DCs did not readhere to tissue culture surfaces and did not proliferate, even when cultured with mitogenic doses of concanavalin A and lipopolysaccharide. Finally, DCs did not change their cytologic or surface properties after 3 days of culture. These observations extend the evidence that DCs are a novel cell type and provide useful properties and techniques for their further study.

[Juvenile arthritis reevaluated in rheumatology in adult age. 30 cases]

The authors describe and comment on 30 observations of peripheral polyarthritis starting before puberty and reveluated in an adult rheumatologoy service at the average age of 29 and during an observation period of about 16 years. The actual classification of juvenile polyarthritis proves to be valid in this group since the clinical forms are still observed in adulthood. However, during the evolution, there is a shifting from one form to another. The systemic forms can reoccur in adulthood even after several years of quiescence, accompanied by visceral complications. The pauciarticular forms as a rule remain benign. As in childhood, they frequently show antinuclear factors. Some forms, initially peripheral, can show axial signs. The presence of HLA B27 antigens allow them to be linked up with ankylosing spondylarthritis. But this is not the case for all the forms with sacroiliac functions. The evolution since childhood is often characterized by long remissions which can still persist by the time of the visit, which is then motivated by resulting mechanical and local arthrotic problems. Despite often severe anatomical symptoms, the functional handicap is limited, allowing quite a remarkable adaptation. Most of the patients lead an active professional life. Yet despite this and despite an often satisfactory sex life, half of the patients have a psychological handicap which makes it necessary for them to be placed under special carl. No therapeutic conclusion, particularly about the efficiency of the basic therapy, can be drawn from this study.

Difference in the effect of immobilized ligands on the Fc and C3 receptors of mouse peritoneal macrophages in vitro

The function of the Fc and C3 receptors on the free surface of normal and endotoxin activated mouse peritoneal macrophages seeded on glass bound antibody--antigen (AbAg) complexes or complement was examined. We found that the glass bound AbAg complexes interfered with attachment and internalization of particles recognized by the Fc receptor. The C3 receptor function in these cells was not affected. On the other hand, normal and activated macrophages seeded on glass bound complement showed no change in the function of the C3 and the Fc receptors.

Differences in the mode of phagocytosis with Fc and C3 receptors in macrophages

Mouse macrophages, activated in vivo or in vitro, were made to internalize sheep erythrocytes opsonized with IgG or IgM and complement. Scanning electron microscopy and transmission electron microscopy were performed at various times after the transfer of the cultures from conditions favoring attachment to conditions favoring internalization. The receptors for Fc and C3 were distributed randomly over the macrophage surface with the exception of the extreme periphery, were Fc receptors were more abundant. The E-IgG were ingested by means of thin membrane extensions rising from the macrophage surface and enclosing the opsonized particles tightly in a cup-like structure protruding from the macrophage surface. Only afterwards were the covered particles drawn into the cell body proper. The E-IgMC were seen to sink directly into the macrophage cytoplasm without apparent involvement of membrane extensions. Experiments with cytochalasin B suggested that microfilaments were essential for the phagocytosis by Fc but much less important with the C3 receptor.