Biocompatibility of Biopolymers

This study examines the biocompatibility of two different syn thetic copolymers; a water soluble copolymer based on [N-(2-hydroxypropyl) methacrylamide] (HPMA) and an insoluble polymer based on 2-hydroxyethyl methacrylate (HEMA). Activation of classical and alternative complement pathways, phagocytic function, bone marrow status, and humoral immune re sponses were assessed after long-term application of the copolymers to mice of the C57BL/10ScSn strain. Histological examination was also performed on sec tions of liver, spleen and kidney. Our results indicate that a total dose of 2 g of HPMA copolymer/1 kg of body weight and 2.5 x 109 particles/mouse of HEMA microspheres did not affect any of the immune parameters that were studied.

High-molecular weight star conjugates containing docetaxel with high anti-tumor activity and low systemic toxicity in vivo

The star polymer-docetaxel conjugates exert a much higher therapeutic activity and yet a lower systemic toxicity than free DTX.

Surface modification of polyimide sheets for regenerative medicine applications

In the present work, two strategies were elaborated to surface-functionalize implantable polyimide sheets. In the first methodology, cross-linkable vinyl groups were introduced on the polyimide surface using aminopropylmethacrylamide. In the second approach, a reactive succinimidyl ester was introduced on the surface of PI. Using the former approach, the aim is to apply a vinyl functionalized biopolymer coating. In the latter approach, any amine containing biopolymer can be immobilized. The foils developed were characterized in depth using a variety of characterization techniques including atomic force microscopy, static contact angle measurements, and X-ray photoelectron spectroscopy. The results indicated that both modification strategies were successful. The subcutaneous implantation in mice indicated that both modification strategies resulted in biocompatible materials, inducing only limited cellular infiltration to the surrounding tissue.

Oral administration of Parabacteroides distasonis antigens attenuates experimental murine colitis through modulation of immunity and microbiota composition

Commensal bacteria have been shown to modulate the host mucosal immune system. Here, we report that oral treatment of BALB/c mice with components from the commensal, Parabacteroides distasonis, significantly reduces the severity of intestinal inflammation in murine models of acute and chronic colitis induced by dextran sulphate sodium (DSS). The membranous fraction of P. distasonis (mPd) prevented DSS-induced increases in several proinflammatory cytokines, increased mPd-specific serum antibodies and stabilized the intestinal microbial ecology. The anti-colitic effect of oral mPd was not observed in severe combined immunodeficient mice and probably involved induction of specific antibody responses and stabilization of the intestinal microbiota. Our results suggest that specific bacterial components derived from the commensal bacterium, P. distasonis, may be useful in the development of new therapeutic strategies for chronic inflammatory disorders such as inflammatory bowel disease.

Oral administration of probiotic bacteria (E. coli Nissle, E. coli O83, Lactobacillus casei) influences the severity of dextran sodium sulfate-induced colitis in BALB/c mice

Our study examined whether repeated preventive oral administration of live probiotic bacterial strains Escherichia coli O83:K24:H31 (Ec O83), Escherichia coli Nissle 1917 O6:K5:H1 (Ec Nis) and Lactobacillus casei DN 114001 (Lc) can protect mice against dextran sodium sulfate (DSS)-induced colitis. A significant decrease in average symptom score was observed in Ec O83-, Ec Nis- and Lc-pretreated group (p < 0.05). Significant differences in body mass loss between Lc pretreated mice with DSS-induced colitis were found when compared with nontreated mice (p < 0.05). PBS pretreated mice had a significantly shorter colon than Ec O83-, Ec Nis- and Lc-pretreated mice (p < 0.05). Administration of Lc significantly decreased the severity of DSS induced histological marks of inflammation (p < 0.05). A significant difference (p < 0.05) was also found in specific IgA level against given probiotic in enteral fluid between colitic mice and healthy mice pretreated with Ec 083 and Ec Nis.

Interaction of mucosal microbiota with the innate immune system

Organisms live in continuos interaction with their environment; this interaction is of vital importance but at the same time can be life threatening. The largest and most important interface between the organism and its environment is represented by surfaces covered with epithelial cells. Of these surfaces, mucosae comprise in humans approximately 300 m2, and the skin covers approximately 1.8 m2 surface of the human body. Mucosal tissues contain two effector arms of the immune system, innate and adaptive, which operate in synergy. Interaction with commensal bacteria, which outnumber the nucleated cells of our body, occurs physiologically on epithelial surfaces; this interaction could pose the risk of inflammation. The mucosal immune system has developed a complex network of regulatory signalling cascades that is a prerequisite for proper activation but also for a timely inactivation of the pathway. As demonstrated in gnotobiotic animal models of human diseases, impaired regulation of mucosal responses to commensal bacteria plays an important role in the development of several inflammatory and autoimmune diseases.

LF 08-0299 in the prophylaxis and treatment of chronic rejection in a rat aortic allograft model

Chronic rejection is the major cause of late kidney allograft failure. We evaluated the efficacy of LF 08-299 (LF), an analogue of 15-deoxyspergualin, in a rat aortic allograft model of chronic rejection. BN aortic allografts were transplanted to Lew recipients. LF was administered at a dose of 6 mg/kg and 2.5 mg/kg on days 0-20 and 6 mg/kg on days 60-90. CyA was used at a dose of 5 mg/kg on days 0-20. Untreated isografts and allografts were used as controls. Histological changes and immunohistochemistry were monitored sequentially at 8, 12, 16 and 20 weeks. There were no differences in intimal proliferation between LF-treated allografts and untreated or CyA-treated controls. Only a tendency in adventitial infiltration reduction was seen in LF-treated animals. We found a significantly less pronounced reduction in media diameter in LF-treated animals. We concluded that LF 08-0299 is only able to reverse reduction in media thickness in aortic allografts, but not intimal proliferation in this model of chronic rejection.

The influence of a colonic microbiota on HPMA copolymer lectin conjugates binding in rodent intestine

Germ-free (GF) animals lack a colonic microflora like that seen in conventional (CV) animals. Bacterial presence plays a role in the development of glycoproteins in the gastrointestinal (GI) tract; the absence of a microbiota has been seen to suppress the production of certain glycoproteins and glycolipids. Binding patterns of lectins are modified when glycoprotein structures are altered (e.g., during development or disease). Little information on lectin binding patterns in mature GF animals is available. We examined the binding of free and N-(2-hydroxypropyl)methacrylamide (HPMA) copolymer-conjugated fluorescein isothiocyanate (FITC)-labeled wheat germ agglutinin (WGA) [P(HPMA)-(WGA-FITC)] and FITC-labeled peanut agglutinin (PNA) [P(HPMA)-(PNA-FITC)] in CV and GF mouse colon with and without neuraminidase pretreatment. Anti-Thomsen-Friedenreich (TF) antigen (a development and disease-related glycoprotein) antibody binding was also examined in these tissues. Subtle differences were seen in the binding patterns between CV and GF animals. CV animals showed strong P(HPMA)-(WGA-FITC) binding in goblet cells, but minimal P(HPMA)-(PNA-FITC) binding was visible. In GF animals, luminal surface binding of P(HPMA)-(WGA-FITC) was visible, and goblet cell binding of P(HPMA)-(PNA-FITC) was seen. These subtle changes suggest that altered glycoprotein expression occurred under GF conditions.

Detection of ICAM-1 in experimentally induced colitis of ICAM-1-deficient and wild-type mice: an immunohistochemical study

Adhesion molecules (e.g. ICAM-1, CD 54) are known to be upregulated on activated vascular endothelial cells during inflammatory reactions. To study the role of ICAM-1 in intestinal inflammation in vivo, we induced acute experimental colitis in wild-type (C57BL/6) mice and ICAM-1-deficient mice, by feeding the animals with 3% dextran sodium sulphate (DSS) in drinking water for 7 days. In the control strain the immunohistochemical staining showed a very pronounced endothelial upregulation of ICAM-1 after the DSS treatment observed in areas of inflammatory infiltrate, especially in venules or arterioles of the propria and submucosa, and partly in the mesocolon. DSS-fed ICAM-1-deficient mice showed no endothelial enhancement and only faint staining of venules or capillaries approaching that encountered in the control ICAM-1-deficient animals. Our data indicate that ICAM-1 may play a crucial role in the development of acute intestinal inflammation, consistent with our finding that ICAM-1 deficiency can obviate severe forms of experimentally induced colitis in mice.

Ultrastructure of rat aortic grafts

This study compares the ultrastructure of three syngeneic and three allogeneic grafts of rat abdominal aorta (Lewis to Lewis and BN to Lewis, respectively); the tissue was sampled three months after transplantation (TPL). The endothelial plate was preserved and mononuclear cell adherence was absent. In syngeneic grafts the intima and media remained close to normal with well-preserved smooth muscle cells (SMC). The thickened allograft neointima consisted of elongated spindle cells and rich intercellular matrix. The cells were typical SMC without apparent signs of dystrophy or degeneration. On the other hand, most SMC of the media showed complete disruption and disorganization of membrane and organelles suggestive of accomplished necrosis. However, the framework of elastic lamellae was preserved, without apparent ruptures or lytic changes. Intraintimal migration of medial SMC was not recorded while some cytoplasmic strips were seen to extend across the outer elastic lamella (possible rudimentary outgrowth of SMC?). Lymphocytes and histiomonocytic cells (macrophages) were found in the adventitia but not in the destroyed media. Thus electron microscopy elucidated the histological picture of "anuclear allograft media" and confirmed the predominance of SMC in the thickened neointima. However, signs of the mediointimal SMC invasion were not apparent three months post TPL.

Morphology and immunohistochemistry of rat aortic grafts

Allotransplantation (TPL) of the abdominal aortic segments of BN donors was performed in 32 Lewis recipients with or without cyclosporin A (CyA) immunosuppression, and the vascular changes were compared to those of 10 syngeneic grafts (Lewis-->Lewis) and to the autologous rat aortae. The vessels were examined 2, 3, 4 and 5 months post TPL by light microscopy, the thickness of intima and media was measured morphometrically and the cell infiltration of adventitia and intima was assessed semiquantitatively. Thirty-six aortae were examined by three-step enzyme immunohistochemistry (proof of selected differentiation, proliferation, cytoskeletal and connective tissue matrix antigens). The adventitia displayed an intense focal and scattered mononuclear cell infiltration; it was more discrete and focal in the intima. This cellularity persisted in the allografts but disappeared from the intima and was reduced in the adventitia of the isografts after four and five months. Disseminated ED1+ activated macrophages were the most prominent population of infiltrates whereas modest numbers of adventitial ED2+ tissue macrophages remained constant throughout the intervals examined. CD4+ cells (focal and scattered) outnumbered (roughly twice) the scattered CD8+ lymphocytes; both these types were rare in the intima. Leukocyte invasion of the media was lacking (except for scarce isolated CD8+ cells in some allografts). In syngeneic grafts the smooth muscle cells (SMC) of media remained intact and the intimal thickening was slight to absent (about 5 microns) four and five months post TPL. On the other hand, the allograft media underwent severe destructive changes (karyolysis, depletion of alpha-SMC actin, focal calcification and general thinning without rupture or aneurysm). The prominent allograft intimal thickening (70-80 microns) was due to the proliferation of longitudinally oriented myointimal cells (alpha-SMC actin, FD2, PCNA and Ki67+) and an increase in matrix substance (strong metachromasia and positivity of chondroitin-sulfate proteoglycan). The deposition of lipids remained discrete, without atheromatous plaques and mural thrombosis. All changes were comparable in CyA-treated and untreated animals. Thus the main lesions of the allografts were (i) persistent mononuclear infiltration chiefly in adventitia, (ii) destruction of medial SMC, and (iii) intimal thickening by proliferation of myointimal cells. At the postTPL intervals examined the proliferation and intimal migration of medial SMC were not apparent and a morphological correlate of significant anti-medial-SMC cytotoxic attack was lacking.

[Immunohistochemistry of a biopsy of an allotransplanted kidney]

BACKGROUND

Cellular rejection infiltration of the interstitium is the basic histological finding in biopsies of transplanted kidneys, and leukostasis in the muscular arteries and glomeruli is an important sign of exacerbating rejection. For better understanding and more accurate interpretation the authors used immunohistochemistry.

METHODS AND RESULTS

The authors examined 282 tissue specimens from 208 grafts using the two- or three-step immunoenzyme method with 28 mono- or polyclonal antibodies specific for a series of differentiation and activation leukocytic antigens, adhesion molecules and selected cytokines. In the compact component of the rejection infiltrate CD4+ lymphocytes with expression of CD 45 RA antigen predominated while in the disperse component there were mostly macrophages (CD68, 14, 11b); their number correlated significantly with the parenchymatous damage, similarly as intraarterial and glomerular accumulation. The disperse infiltrate and adherent cells expressed CD45 RO (rarely CD25) and integrin molecules of the series CD11 and CD49 CD57+ lymphocytes penetrated into the tubules but did not accumulate in the blood vessels. As to adhesive molecules of the "Ig superfamily", CD106 (VCAM-1) was more important than CD54 (ICAM-1) and its arterial and mesangial expression correlated with the rejection damage. Evidence of cytokines (IL1, IL2, TNF alpha, beta) did provide neither unequivocal results nor correlations.

CONCLUSIONS

Immunohistochemistry improves considerably the accuracy of bioptic evaluation of rejection nephropathy and some antigens (e.g., CD68, CD14, CD45 RO., CD57, CD106) are suitable for diagnostic practice. With their aid it is easier to evaluate the activity of rejection, assess the probability of vascular lesions in specimens without affected vessels and detect more sensitively intravascular stasis and adhesion of leukocytes.

[Light chain deposition disease as a cause of renal failure]

The objective of the paper is to draw attention to a rare cause of rapidly progressing renal failure which developed in the course of four months as a result of light chain deposition disease. The authors submit two case-histories of the disease assessed by renal biopsy after previous clinical and laboratory suspicion of monoclonal gammapathy. In one patient in the sternal punctate plasmacytoma was diagnosed and in the second case it was not possible to detect any type of monoclonal gammapathy or another possible cause of disease. Renal failure was in both cases irreversible and both patients were enlisted in regular haemodialyzation treatment.

[Repeat kidney transplantation]

BACKGROUND

The objective of the study was an analysis of results of repeated kidney transplantations (Tx2, Tx3) implemented during the first 29 years of activities of the Transplantation Centre of the Institute of the Clinical and Experimental Medicine in subjects with a different maintenance immunosuppression.

METHODS AND RESULTS

The retrospective study pertains to 134 Tx2 and 17 Tx3 in 134 non-diabetic subjects: 43 of them had during Tx1 and Tx2 (1966-1981 and 1966-1985 resp.) immunosuppression on the basis of azathioprin (Aza, sub-group AA), 42 during Tx1 (1972-85), Aza, while during Tx2 (1984-85) immunosuppression on the basis of cyclosporin (CyA, subgroup AC) and 49 both during Tx1 and Tx2 (1985-93 and 1986-95 resp.) CyA (subgroup CC). Compared was survival of grafts by the actuarial method (with regard to all losses regardless of cause) by the end of the 4th year inside the subgroups (Tx2, vs. Tx1 and Tx3 vs. Tx2 in the same subjects) and between subgroups (Tx1 vs. Tx1 and Tx2 vs. Tx2 in different subjects). Moreover in paired investigations the survival of recipients and grafts after Tx2 was compared after immunosuppression on the basis of CyA with the same parameters after Tx1 in different subjects with the same immunosuppression, operated at approximately the same time (n = 81) and survival of subjects with Tx1 + Tx2 on the CC regime regardless whether the second grafts functioned at the time of the last examination, with survival of subjects after Tx1 where after graft failure Tx2 was not performed (n = 34). Prophylaxis with antilymphocyte globulins was not used. Survival of second and first grafts did not differ in any of the subgroups, third grafts survived at the end of the third year more frequently than second grafts (66 vs. 18%, p < 0.01). Second grafts in CC survived more than in AA (55 vs. 28%, p < 0.01). In the paired study Tx2 vs. Tx1 the survival of grafts and recipients was the same (88 vs. 89%, N.S. and 47 vs. 62% resp.), in the paired study Tx1 + Tx2 vs. Tx1 more subjects with Tx1 + Tx2 survived 10 years after Tx1 than subjects who did not have Tx2 (82 vs. 49%, p < 0.05).

CONCLUSIONS

A further transplantation of the kidney after functional loss of the first graft is the method of choice: the mortality is low, the probability of several years' function is considerable and the prognosis as regards quality and length of life better than with regular dialysis treatment.

Lesion of leukocytes, erythrocytes, and mesothelial cells by the coelomic fluid of Eisenia foetida earthworms

Coelomic fluid of Eisenia foetida earthworms is known to exert strong proteolytic, hemolytic, bacteriostatic, and cytolytic properties. Ultrastructural observations revealed that coelomic fluid causes multiple ruptures and defects in the erythrocyte membrane as well as in the membrane of murine peritoneal leukocytes. Incubation of peritoneal cells in coelomic fluid resulted in a disorganization of the macrophage surface microvilli, changes in the organization of cytoplasmic organelles and disruption and degranulation of mast cells. Severe mesothelial damage was observed after intraperitoneal administration of the coelomic fluid.

Antigenic stimuli do not influence thymic B lymphocytes: a morphological and functional study in germ-free and conventionally reared piglets

We have recently reported that thymic B lymphocytes (TBL) are the first B-cell subpopulation undergoing isotype switching to IgG and IgA during embryonic life. The aim of this study is to analyze the influence of antigenic stimulation on TBL location and activity using a germ-free (GF) newborn pig model, in which maternal antibodies and antigens do not affect B-cell development. Immunohistological analysis showed that TBL were disseminated mainly in the thymic medulla. There were no differences in the distribution of TBL, both in GF newborn piglets before and after colonization with Escherichia coli and in older conventionally reared (CONV) piglets. The number of immunoglobulin (Ig)-secreting cells measured by the ELISPOT method was not influenced by microflora and food antigens. IgM-positive cells secreting IgM and CD45RC-positive cells spontaneously producing IgM, IgG, and IgA were detected in newborn thymus. Our findings suggest that TBL differentiation and Ig switching to IgG and IgA-secreting cells is not influenced by external antigens and that the thymic microenvironment plays an important role in this process.

Cellular expression of the cytolytic factor in earthworms Eisenia foetida

Coelomic fluid of earthworms contains a 42 kDa protein designated CCF-1 (coelomic cytolytic factor 1), which accounts for approximately 40% of cytolytic activity of the entire coelomic fluid. CCF-1 was documented to be present on cells of the mesenchymal lining of the coelomic cavity as well as on free coelomocytes. Both cellular and humoral levels of CCF-1 were significantly increased after parenteral injection of endotoxin. Moreover, CCF-1 seems to be involved in cell mediated cytotoxicity, because cytotoxic activity is blocked in the presence of anti-CCF-1 monoclonal antibody (mAb).

Anti-gliadin antibodies in patients with celiac disease cross-react with enterocytes and human calreticulin

One of the characteristic features of celiac disease is an increase in anti-gliadin antibodies (Abs). Recently we found that some of the monoclonal Abs to gliadin cross-react with molecules on rat enterocytes. One of these cross-reacting molecules was identified as rat calreticulin. This study shows that the levels of serum IgA Abs to gliadin, rat, and human enterocytes; purified enterocyte antigens; and calreticulin in sera from patients with active disease were significantly higher than in patients on a gluten-free diet and healthy controls (P < 0.001). Anti-gliadin Abs were isolated by affinity chromatography from the sera of six active celiac patients. The reactivity of these anti-gliadin Abs was demonstrated to be significantly higher (P < 0.05) with human enterocytes and human calreticulin than with other antigens tested. Furthermore, using isolated patients' anti-gliadin Abs bound to Sepharose 2B, two main proteins of molecular mass 62 and 66 kDa were purified from a lysate of human enterocytes. The 62-kDa enterocyte antigen was identified as human calreticulin. These findings suggest that anti-gliadin Abs may play a pathogenic role in celiac disease by cross-reacting with enterocytes. Calreticulin in enterocytes may be one of the putative targets for autoimmune reactions.

[Charge interactions of immune deposits in glomeruli (experimental study)]

An i.v. injection of 8-40 mg (kg cationized and heat-aggregated rabbit or human Ig (cat-aggr RIg,-HuIg; pI 9.5) elicited a strong diffuse linear fixation in rat glomerular capillaries revealed by one-step immunofluorescence or immunoenzyme histochemistry 1 and 2 h post-injection. Preferential binding to the lamina rara externa (LRE) was documented in ultrastructure by preembedding and postembedding assays (HRP-coupled antibody and protein A-colloidal gold, respectively). After 24 and 48 h the glomeruli were negative. Polyethylenimine (PEI)-reactive polyanion of LRE was significantly reduced 1 h after cat-aggr-Ig; depletion persisted even after 48 h. Non-cationized Ig aggregates did not bind to the glomerular capillaries. A subsequent i.p. injection of swine anti-rabbit-Ig antibody (SwAR, 15 mg i.p. after 4 h) produced the same linear binding of both two antigens which, however, persisted after 10 days and assumed a granular pattern. After presensitization with RIg (1-2 mg i.p. or s.c.; 4 days before cat-aggr RIg) the early linear fixation underwent a gradual transformation into the granular pattern and deposits of mesangial, rarely of epimembranous type were found 1 week after cat-aggr RIg and later. RIg and SwIg were proved in both types of deposits. After 2 weeks both rat Ig and C 3 were present, too. Rarefaction of deposits and their concentration in the vascular poles took place during 3 months, and deposits also appeared in the media of vas afferens. The antigen load did not produce an acute glomerulonephritis or significant proteinuria; slight focal mesangial sclerosis and a discrete increase in serum creatinine were noted after 2-3 months. To sum up: The one-shot charge interaction is prompt but short-lived whereas the local binding of additional proteins, especially after a specific preimmunization, significantly prolongs the contamination of glomeruli and promotes the build-up of immune complex-type deposits which gradually retreat to the mesangial stalk and vascular pole.

Abnormal differentiation of thymocytes induced by free cyclosporine is avoided when cyclosporine bound to N-(2-hydroxypropyl)methacrylamide copolymer carrier is used

BACKGROUND

The side effects of cyclosporine (CsA)-including nephrotoxicity and abnormal differentiation of thymocytes developing in the thymus-can be decreased or even avoided using targeted conjugates of CsA, where both targeting moiety and drug are bound to water-soluble polymeric carrier based on N-(2-hydroxypropyl) methacrylamide (HPMA).

METHODS

Irradiated, syngeneic bone marrow transplanted-mice (BALB/c and A/Ph) were treated intraperitoneally for 4 weeks with 20 mg/kg of free CsA, HPMA-conjugated CsA, or antibody-targeted HPMA-bound CsA. Immunohistology of the thymus was performed together with two-color flow cytometry to detect the effect of different forms of CsA on individual thymocyte subpopulations.

RESULTS

. We have shown that free CsA strongly abrogated T-cell development. The appearance of mature thymocytes expressing CD3(high) is almost completely inhibited (1.8%) after free CsA treatment, whereas these cells are well detectable in controls (22%) and HPMA polymer-bound CsA-treated animals (19%). Immunohistological studies have shown acellular rests of the medulla after free CsA treatment, whereas well-stained medullary thymocytes were detected in controls and after exposure to antibody-targeted HPMA. conjugated CsA.

CONCLUSIONS

HPMA-conjugates of CsA are generally more specific in their targeting to T lymphocytes. It was found that nonspecific binding of CsA to erythrocytes and plasma lipoproteins is significantly reduced using anti-CD3 targeted, HPMA polymer-bound CsA In addition, the entry of these macromolecules into the thymus is limited-probably due to the blood-thymus barrier-and HPMA conjugates of CsA, unlike free drug, do not abrogate T-cell development in bone marrow transplanted mice.

The course of the mandibular canal in the growing miniature pig

Miniature pigs are extensively used as laboratory animals in studies concerning craniofacial growth and adaptation. However, in contrast to the vast amount of literature regarding the overall growth pattern of the pig's mandible, little is known about the internal structures of the mandible such as the mandibular canal. In order to investigate the position of the mandibular canal (MC) and the thickness of its buccal and lingual walls, a cross-sectional study was performed on female miniature pigs MINI-LEWE covering the period from newborn to adult. The position of the MC was analyzed at bony segments that were obtained by cutting the drys mandibles interdentally. At each segment a central point of the MC was defined and its relation to the buccal and lingual margin of the mandible was measured. Located at the lower part of the mandibular corpus, the MC runs in the form of an arch within the sagittal plane in anterior direction, getting enlarged into the form of an ampulla in the molar and premolar region. Whereas during the primary dentition the biggest size of the MC was found behind the third deciduous molar, during the secondary dentition the biggest size of the MC was seen in the region of the first and second permanent molar. With regard the buccolingual aspect, the central point of the MC was found mainly in the center of the mandibular corpus. Between the 2nd and 5th month as well as at the beginning of the 18th month the thickest canal wall existed on the buccal side. In the period of the eruption of the succedaneous teeth, however, the lingual wall was thicker than the buccal wall. Results suggest that the definite course of the MC achieves relatively early in the miniature pig with the completion of the primary dentition. There were no major changes of the position of the MC in the postnatal period suggesting that the age factor has only a minor effect on the location of the MC.

Morphology of rat kidney and thymus after native and antibody-coupled cyclosporin A application (reduced toxicity of targeted drug)

This study compares the toxic effects of native cyclosporia A (CyA) with those of targeted CyA that is conjugated with the anti-rat-thymocyte antibody of rabbit origin via the N-(2-hydroxypropyl)methacrylamide (HPMA) carrier bearing digestible, reactive oligopeptide side chains. Ten toxic doses of native CyA (50 mg/kg i.p.) given to young adult rats in the course of 14 d produced a severe renal lesion-diffuse microvacuolization of the proximal tubules in the deep cortex, and hypergranulation of juxtaglomerular regions. Severe atrophy of the thymic medulla was documented by morphometry. In the cortex the epithelial reticular (but not deep interdigitating) cells showed ultrastructural signs of severe degeneration and lysis. The immature CD4+8+ double-positive cortical lymphocytes were preserved whereas the single-positive medullary thymocytes were greatly depleted; there was also a restriction of MHC class II antigen expression in the medulla. The number of medullary B cells was increased. The cytokeratin net was focally shrunken in the cortex and almost negative in the medulla, with loss of Hassall's corpuscles. After ten corresponding doses of antibody-targeted conjugated CyA no damage to the renal tubules and arterioles appeared and the antiGBM or immune-complex deposition was absent. The thymus had a normal medulla with numerous mature thymocytes and the cortical epithelial reticulum remained well preserved. Thus, the main toxic effects of CyA could be eliminated by targeting. The T-cell-targeted drug was tested for preserved immunosuppressive properties and non-toxic character of HPMA copolymer carrier.

Molecular mimicry as a possible cause of autoimmune reactions in celiac disease? Antibodies to gliadin cross-react with epitopes on enterocytes

Structural similarities between external antigen and self components are believed to be one of the possible causes of autoimmunity. This study describes the presence of similar structures shared by gliadin and enterocyte surface molecules recognized by antigliadin mAbs. The reactivity of mAbs to gliadin was followed by ELISA using fixed enterocytes, their brush-border membranes, or purified enterocyte antigen. The specificity of reaction was confirmed by ELISA inhibition studies and by immunohistochemical staining of rat tissue sections using biotin-avidin-peroxidase technique. Immunoprecipitation analysis of 125I-labeled intestinal epithelial cells using antigliadin mAb revealed the presence of two main cross-reactive molecules of 28 and 62 kDa. The 62-kDa and an associated 66-kDa protein were isolated by affinity chromatography. Immunoblotting analysis showed that a 28-kDa protein detected by immunoprecipitation also reacted with IgA of celiac disease patient sera.

[Early changes in vascular graft rejection in transplanted kidneys: the past and the present]

BACKGROUND

With maintenance azathioprine+prednisone and in biopsies performed exceptionally earlier than in the 4th week (1966-1984, 476 cadaveric kidney transplantations), prevalence of obliterative arteriopathy (OA, transmural arteritis, 4/III/v3 Banff classif.) was 22.1%, with graft loss by rejection within 6 mos. in 89.4%. The aim of this analysis was to study prevalence and prognostic importance of the former and of further early vascular lesions in subjects with maintenance cyclosporin A using biopsies performed as early as in the 1st week.

METHODS AND RESULTS

In a retrospective study on 449 transplantation (1987-92, cyclosporin A+prednisone+azathioprine, 64.7% grafts histologically--mostly repeatedly--examined), prevalence and prognostic classification (A-good, B-uncertain, C-poor prognosis) in recipients with OA, with cellular arteriopathy (CA, intimal arteritis, 4/II-III/v2-v3 Banff classif.) and with minimal arterial lesions (MZ) were assessed. Prevalence of OA was found to be 7.1% transplantations, with graft loss by rejection within 6 mos. in 71.9%, and with A:C proportion 25.0%: 62.5%. CA was found in 5.1% and showed A:C proportion 34.7%: 34.7%; in 6/13 cases with repeated histology, OA was later encountered, which is a strong point against its humoral pathogenesis. Prevalence of MZ was 10.9%, with A:C proportion 40.8: 4.1%.

CONCLUSIONS

Both OA and CA are related to rejection, while the etiology of MZ remains to be clarified. With cyclosporine, prevalence of OA markedly decreased and its prognosis somewhat improved; secondary prevention is possible when an early diagnosis (early and repeated biopsies) is done and immediate treatment (antilymphocyte globulins) started.

[Kidney transplantation and tumors]

BACKGROUND

In conjunction with organ transplantation and subsequent treatment there is a number of influences which potentiate the development and possibly the growth of tumours. This applies naturally also to transplantations of the kidneys. The objective of the present study was to assess the frequency and type of tumours in patients after renal transplantation and compare these results with data of the at present most extensive worldwide register in Cincinnati (CTTR).

METHODS AND RESULTS

The authors analyzed a group of 879 patients where within the period between March 21, 1966 and Sept. 29, 1992 a total of 989 renal transplantations were performed from dead relations-934 or from living relations (55); in 38 patients combined transplantations of kidney and pancreas were performed. The group comprised 59% men and 41% women. In the course of years the pattern of prophylactic immunosuppression changed: up to 1984 the basic drug was azathioprin combined with prednisone, during the same year cyclosporin A was introduced as a rule in a triple combination with azathioprin and prednisone; less frequent was the combination of cyclosporin A and prednisone. For antirejection treatment corticoids were used, later supplemented with polyclonal or monoclonal antibodies. During the period 1966-1992 tumourous diseases were diagnosed in 32 patients (3.64%); in two of these patients; combined transplantation of the kidney and pancreas was performed (5.3%). There was no difference in the frequency of tumours in patients with immunosuppressive medication (azathioprin with prednisone-3.80%) and cyclosporin A (3.51%). The mean age of the patients at the time of diagnosis of the tumour was 50.2 years, the interval after transplantation was 42.2 months (in patients treated with azathioprin 57 months, in the group treated with cyclosporin A 29.2 months). As far as the location of tumours is concerned, tumours of the skin predominated 25% (as compared with CTTR where it was 30%), tumours of the patient's own kidneys 21.9% and of the urinary pathways 15.6%, tumours of the gastrointestinal tract 12.5%, lymphomas in 9% (as compared with 15-20% in CTTR), tumours of the lungs 6.25% and other localizations also 6.25%. Some tumours frequently encountered in the population (lung cancer, cancer of the prostate, breast, colorectal carcinoma) are less frequent in patients after transplantation (CTTR); however, this fact was not confirmed by the authors. In renal tumours and tumours of the efferent urinary pathways data on analgetic nephropathy were encountered very frequently.

CONCLUSIONS

The prevalence of tumours of various organs in patients after transplantations of the kidneys are not a frequent but a very serious complication. Its causes are multifactorial. The group after renal transplantations in the Czech Repubic has some deviations as compared with CTTR as regards affection of organs.

A new approach to in vitro studies of antigenic response in earthworms

A method for in vitro cultivation of earthworm gut wall tissue explants is described. Tissue explants are able to respond to protein antigen by secretion of antigen-binding protein into the culture medium. Large irregular cells and round-shaped cells are released from tissue explants during the cultivation. This method represents an advantageous tool for in vitro studies providing the possibility of parallel assays from the same donor.

[Etiopathogenesis of insudative vasculopathy in transplanted kidneys]

In 99 renal allograft recipients with insudative vasculopathy of graft, mean serum cholesterol levels, prevalence of subjects with hypercholesterolaemia, mean cumulative doses of methylprednisolone, prevalence of subjects with methylprednisolone doses > or = 6,000 mg and prevalence of patients with hypertension, all in the period between transplantation and the first diagnostic biopsy, were compared between 51 those with conventional and 48 with cyclosporine maintenance immunosuppression. In subjects treated with cyclosporine the lesion was found in biopsies performed sooner and was present more frequently, prevalence of hypercholesterolaemia and of hypertension was similar and that of subjects with both hypercholesterolaemia and hypertension lower than in subjects treated with azathioprine. A positive correlation was present between high doses of methylprednisolone and prevalence of hypertension, regardless of the type of immunosuppression and of severity of vasculopathy. In etiopathogenesis of insudative vasculopathy atherogenic factors are most probably involved, more markedly when azathioprine is used for maintenance immunosuppression. With cyclosporine, changes of graft haemodynamics and possibly also toxic damage to the vessels involved seem to be more important.

On the postnatal growth of the canalis mandibulae in the miniature pig

The shape and the growth of the canalis mandibulae in female miniature pigs, MINI-LEWE, were analysed in 11 postnatal age steps. The lower jaw halves were cut frontally in a defined position and the heights and widths of the canalis mandibulae were measured. Changes in the shape of the canalis mandibulae in the frontal saw cuts were observed with regard to the dentition. After the eruption of the deciduous teeth there was no further change in shape. Growth curves of the mandibular canal's measures reached a peak during the eruption of the deciduous teeth and the first molar, decreasing significantly afterwards. A close correlation was observed between the measures of canal height and canal width. On the other hand there was only a slight correlation with the external measures of the mandible, which suggests that there are different growth processes.

[Therapy in kidney transplant rejection using murine monoclonal IgG2a A1CD3 (Cedetrin)]

BACKGROUND

One of the substances used in recent years to suppress immune reactions after organ and tissue transplantations is mouse IgG2a globulin which acts selectively on CD3 lymphocytes; it is known under the name of Orthoclone (Ortho Co.) An analogous preparation was developed in the Institute of Molecular Genetics, Academy of Sciences, Czech Republic, although the idiotype is different. The authors submit a report on the experience with treatment of rejection of transplanted kidneys.

METHODS RESULTS

Monoclonal mouse globulin IgG2a (Cedetrin) was administered to 20 patients after renal transplantation on account of a rejection episode or progressing rejection; the mean interval after transplantation was 16.1 (range 0.25-96) months; the rejection episode or progressing rejection responded little in the majority of patients to 6-alpha-methyl prednisolone (Urbason, Hoechst, Solu-Medrol, Upjohn). For prophylactic immunosuppression the following combinations were used: cyclosporin + azathioprine + prednisone (17x) or azathioprine + prednisone (3x). Cedetrin was administered by the i.v. route in two to 11 doses a 3 mg substance. Of 20 patients in 6 Cedetrin administration had to be discontinued (allergy, infection, leucopenia, hyperhydration). In 14 the tolerance was satisfactory, the type and frequency of side-effects was similar as after Orthoclone; the antibody formation was less frequent. The specificity of Cedetrin as regards its action on T lymphocytes was confirmed. The effect was good to very good in 6 of 8 patients where the rejection filtrate was histologically active. In 9 patients treated during the first year after renal transplantation the cumulative survival of the graft at the end of the 12th, 24th and 36th month following transplantation was 89%, 67% and 56% resp. Because the therapeutic effect depended on histologically proved rejection activity, the authors consider biopsy of the graft before Cedetrin treatment essential.

CONCLUSIONS

The therapeutic administration of monoclonal mouse globulin IgG2a A1CD3 (Cedetrin), developed in the Institute of Molecular Genetics, Academy of Sciences, Czech Republic, produced by Exbio Co., CR) has a favourable effect on rejection episodes or progressing rejection of transplanted kidneys. Treatment is indicated in confirmed histologically active rejection.

[Graft rejection after changing from cyclosporin A therapy to conventional treatment in kidney transplant patients]

Hundred and twenty live patients after the first transplantation of the kidney from a decreased donor with satisfactory graft function, treated with cyclosporine A combined with prednisone or combined with prednisone or combined with prednisone and azathioprine were divided into three groups: A--20 patients changed during the 6th-9th month after transplantation to conventional azathioprine-prednisone treatment. B--68 patients switched to this treatment during the 10h-15th month following transplantation. K--37 patients who were not switched to other treatment during the mentioned period. Within 3 months after the switched rejection develop in 21% of the patients in group A and 20% patients in group B. The incidence of rejections during a comparable period in group K was significantly lower (3%), as compared with group A and insignificantly lower (14%), as compared with group B. The majority of rejections was documented by biopsy but no morphological difference was found between rejections which developed in patients switched and not switched to other treatment. It was striking that there was a difference, though insignificant, in the sensitivity of rejections to antirejection treatment with methylprednisolone after switch to a different preparation: in group A 25%, in group B 37% and in group K 80%. Patients in group A with rejection after the switch had developed a rejection even before the switch significantly more frequently (in 75%) than in group B (in 7%) and these rejections led significantly more frequently to loss of the graft.

[Rapidly progressing glomerulonephritis with antibodies to glomerular capillary basement membrane]

Antiglomerular basement membrane glomerulonephritis was diagnosed in 14 patients (6 men and 8 women) aged 20 to 59 years. Five patients were found to have Goodpasture s syndrome. 5 rapidly progressive glomerulonephritis. 1 nephrotic syndrome, and 1 had mild glomerulonephritis. Blood pressure, proteinuria and haematuria were not severe in most patients. In 10 patients, the diagnosis was not established before end-stage renal failure had developed. Four patients died of lung haemorrhage, in 3 the haemorrhage was controlled by the treatment, in 3 renal failure without lung haemorrhage occurred, and in 3 renal function improved or was stable. The prognosis improved significantly after plasma exchange together with immunosuppression had been introduced.

Experimental adriamycin nephropathy. Fine structure, morphometry, glomerular polyanion, and cell membrane antigens

Two doses of adriamycin (2 mg/kg i.v.) were administered to young adult rats with a 22-day interval and the kidneys were examined 51, 79, and 107 days after the first injection. Light microscopy showed early prominent intraglomerular microcystic spaces and progressive, though not severe, segmental glomerulosclerosis with focal interstitial scarring and round-cell infiltration. The main features of the ultrastructure were widespread fusion of foot processes, focal cytoplasmic rarefaction of podocytes, and non-specific sclerosis of the mesangium without signs of severe degenerative changes or mesangiolysis. The segmental microcystic structures corresponded to agglomerated intrapodocytic vacuoles. The scatter of glomerular polyanion sites visualized by polyethylenimine-phosphotungstic acid resembled that of control animals but the quantitative assessment revealed a significant reduction. CD4-positive cells were the predominant element of the interstitial infiltrates. Most of the infiltrating cells expressed Ia antigens, whereas Ia-positive intraglomerular resident mononuclear cells were depleted. The adriamycin lesion resembles the post-five-sixths nephrectomy ablation nephropathy in the subpopulations of the interstitial infiltrate but differs from it in the reduction of intraglomerular resident macrophages, the absence of destructive mesangial damage, and reduced segmental glomerulosclerosis. The main feature is the prolonged damage of podocytes, especially of their cytoskeletal system.

[Long-term prognosis in chronic primary glomerulonephritis in relation to urinary findings]

A long-term followed-up group of 993 patients with primary glomerulonephritis (GN) was divided by urinary syndromes, defined according to the degrees of proteinuria and haematuria. Responding morphological diagnoses and prognoses were found for each urinary syndrome. Isolated and predominant haematuria were determined as benign, with stationary course even without immunosuppressive therapy. The prognosis of isolated, even moderate, proteinuria is more serious finding. Its relevance increases with the degree of haematuria. Severe combined proteinuria and haematuria is the most serious urinary syndrome. Both proteinuria and haematuria may be changing in the course of GN and increasing proteinuria points to the future glomerular filtration rate decrease.

Detection of antigen in the coelomocytes of the earthworm, Eisenia foetida (Annelida)

Earthworms, Eisenia foetida, are able to respond to antigenic stimulation by the formation of the antigen-binding molecules by coelomocytes--the effector cells of annelids' defence reactions. The ability to react with gold-labelled antigen was detected in agranular coelomocytes by electron microscopy. Furthermore, flow cytometry analysis used for quantitative evaluation of antigen binding showed significant increase of both antigen-binding cells and the amount of antigen bound per cell after stimulation. The antigen binding was inhibited by preincubation of cells with several similar proteins, although the most potent inhibitor was the immunizing antigen.

[Focal segmental glomerulosclerosis]

Focal and segmental glomerulosclerosis accounted for 4.1% of all primary glomerulopathies. Typical signs of focal and segmental glomerulosclerosis were striking arteriolosclerosis on histological examination, the urinary syndrome of high proteinuria with mild haematuria and frequent nephrotic syndrome. The ten-year cumulative percentage of remissions was 30%. Patients with remission had at the time of biopsy a normal serum creatinine level and no or minimal regressive tubulointerstitial changes. The ten-year cumulative percentage of renal failure was 40%. Presence of nephrotic syndrome, extracapillary proliferation and advanced tubulointerstitial changes, tended to shorten a kidney survival. In one third of the patients the serum creatinine level rose by more than 50 mol/1/year.

Arteriolosclerosis of the human renal allograft: morphology, origin, life history and relationship to cyclosporine therapy

In the decade 1979-1988, 658 biopsies were collected from 568 cadaveric renal allografts. In 118 grafts a non-proliferative insudative vasculopathy (IVA) was found in afferent vessels. Immunosuppression was based on azathioprine (AZA) or on cyclosporin A (CsA), from 1983. The prevalence and extent of IVA has increased significantly since 1984. Light microscopy showed fibrinoid and hyaline masses of varying extent; transmural insudative "knobs", intimal oedema with metachromasia, and microthrombosis were also seen with CsA. The ultrastructure of the insudates was unremarkable but CsA grafts displayed early oedema and hypergranulation of endothelial cells with a disarray of smooth muscle cell (SMC) microfibrils, and pronounced degenerative changes of SMC. Rebiopsy showed stationary IVA in AZA grafts and progression in one-half of CsA-treated patients. Nephrectomy specimens revealed, however, a marked predominance of late rejection endarteritis; in only 3 cases was IVA and/or microthrombosis the possible cause of nephrectomy. The mean donor age was higher in severe IVA in CsA grafts and the mean post-transplantation interval at the time of diagnosis of IVA was significantly shorter in CsA-treated patients. No important differences in cumulative graft survival were seen between grafts with absent, moderate or severe IVA. Unused cadaveric donors' kidneys of comparable age exhibited normal arterioles or a slight focal insudative or hyaline lesion.

Experimental ablation nephropathy. Fine structure, morphometry, cell membrane epitopes, glomerular polyanion and effect of subsequent transplantation

The subtotal (5/6) nephrectomy performed in 23 adult female rats induced severe hypertrophy of residual parenchyma with interstitial fibrosis, tubular dilatation, and focal and segmental glomerulosclerosis (FSG). This ablation nephropathy (AbN) caused proteinuria, progressive renal failure, and hypertension. The extent of FSG was assessed by semiquantitative scoring. The ultrastructure revealed widespread foot process fusion, many dense cytoplasmic inclusions in podocytes, and degenerative changes or disruption of mesangium with glomerular "microcysts". Numerous granular deposits of rat Ig were seen in the glomeruli but a short praeterminal i.v. load by heat-aggregated human Ig did not alter the morphology of AbN and produced discrete and inconstant glomerular deposits. Similarly an i.v. injection of protamine and heparin generated protamine-heparin complexes seen in various layers of glomerular capillary wall, similar to those found previously in normal rats. AbN displayed a partial irregular depletion of polyanion sites reactive with polyethylenimine in lamina rara externa. A significant increase in both glomerular and interstitial Ia+ cells and a marked predominance of W3/25+ cells in the interstitial infiltrates were documented by immunohistochemistry in the remnant kidneys. Both AbN and FSG could be largely corrected (or prevented?) by subsequent syngeneic renal transplantation (TPL; 6 animals). On the other hand a severe AbN was found in two post-ablation residues after unsuccessful TPL with graft necrosis or sclerosis.--AbN has some analogies to various chronic human nephropathies (e.g. FSG) and may explain their progression to the terminal failure. Degenerative and finally destructive mesangial lesion seems to be of prime importance in AbN.

[Type I and III membranoproliferative glomerulonephritis. Clinical picture and prognosis]

Membranoproliferative glomerulonephritis (CN) of types I and III was diagnosed in 154 patients (15.5% out of primary CN). Out of this number 60% were men. During biopsy, one third of the patients were normotensive, 40% were slightly hypertensive and one third suffered from severe hypertension. Mean proteinuria was 6.5 +/- 5.5 g/24 h. In two thirds of the patients erythrocyturia was higher than 35 mil. in Addis' sediment and the findings in the urine were characterised by the proportion between proteinuria and erythrocyturia (p less than 0.001). During biopsy in one half of the patients, the serum creatinine level was already elevated. The presence of creatininemia was found to be directly linked to blood pressure, proteinuria, the degrees of extracapillary proliferation, tubulointerstitial regression and vascular arteriolosclerosis. The cumulative duration of the kidney function within the period of 10-20 years was 41 or 28%, the cumulative cure amounted to 14% 10 years after biopsy.

[Idiopathic membranous glomerulonephritis. Clinico-morphologic relations and prognosis]

Membranous glomerulonephritis (GN) was diagnosed in 61 of 993 patients with histologically confirmed primary GN. Two-thirds of the patients were men. High hypertension was recorded in 7.5% of the patients. A typical finding was marked proteinuria (6.15 +/- 4.88 g/24 h.) with mild erythrocyturia (median 8 million in Addis sediment). At the time of biopsy 86% of the patients had normal creatininaemia, the level of which was positively correlated with the blood pressure and degree of tubulointerstitial regression. The cumulative duration of renal function in 5, 10 and 20 years was 88, 80 and 57%; during the same time intervals 22, 48 and 52% of the patients were cured.

In vivo interaction of bilirubin with the cells of the immune system in mice: an ultrastructural electronmicroscopic study

Morphological evidence revealed the presence of round-shaped particles after application of bilirubin. The possibility of polymerization of bilirubin-albumin complexes is discussed.

Detection of cationic and non-cationic markers in the rat glomerulus by electron probe analysis

Acidic glycans (glomerular polyanion substances) in the rat kidney were visualized ultrastructurally by three cationic markers: colloidal iron, ruthenium red, and polyethylenimine-phosphotungstic acid (PEI-PTA). Heavy metal atoms (Fe, Ru and W) were detected in ultrathin sections by energy-dispersive electron probe microanalysis (EPMA). Characteristic peaks of the locally bound elements were obtained in spectra derived from the dense structures seen by transmission electron microscopy (TEM)--i.e. the glycocalyx of podocytes and/or the polyanion sites in the lamina rara externa of the glomerular basement membrane. Weaker signals were emitted by some extraglomerular structures. This finding may reflect a low concentration of glycans in structures lacking apparent density by TEM, and/or incomplete specificity of the markers, partial dislocation of reactive substances or the presence of an endogenous element (Fe). Experimental argyrosis was elicited by the peroral administration of silver nitrate. Dense Ag precipitates were seen chiefly in the lamina densa and characteristic peaks of silver were displayed in this site by EPMA, and was best demonstrated in non-contrasted sections. A single i.v. injection of Ag proteinate failed to produce glomerular pigmentation. The only dense granular product in tubular cells yielded characteristic peaks of Fe (endogenous siderosomes) but EPMA excluded detectable amounts of silver.

[Status of information of interested lay persons: results of a questionnaire survey by the Styrian Heart Association]

181 interested individuals (75 males, 106 females; range 16 to 84 years) responded to a questionnaire issued within the information and instruction courses of the Styrian Cardiovascular Non-professional Society. The main topic of the questionnaire concerned information gained via media, possible risk factors leading to cardiovascular diseases and any changes in living conditions due to such facts. The results show clearly that the general knowledge in this field especially in younger subjects is disappointing and further intensive information and instruction would be urgently required.

Failure to detect the presence of pluripotential haemopoietic stem cells in the mouse brain

Single cell suspensions prepared from adult mouse brains were tested for the presence of pluripotential haemopoietic stem cells (colony-forming units, CFU) by transfer into an irradiated recipient and enumeration of the CFU in the recipient's spleen. In contrast to the findings of others (Bartlett, 1982), we did not detect CFU after injection of brain cell suspensions, although they were detectable after inoculation with bone marrow cells. The number of CFU in recipients after transfer of increasing numbers of brain cells was the same as that detected in the irradiated controls which had not received any transferred cells. Finally, cells from the brain, in contrast to bone marrow cells, were not able to protect recipient animals from the effects of lethal irradiation.

Antibody-directed affinity therapy applied to the immune system: in vivo effectiveness and limited toxicity of daunomycin conjugated to HPMA copolymers and targeting antibody

The applicability of targeting therapy intervention in lymphatic tissue was studied. The effect was measured as the inhibition of anti-sheep red blood cell antibody response expressed in plaque-forming cells. Daunomycin was used as the effective drug and polyclonal and monoclonal anti-Thy 1.2 or anti-Iak antibody served for targeting. Both components were coupled to a soluble N-(2-hydroxypropyl)methacrylamide (HPMA) copolymer with oligopeptidic side sequences which permitted a controlled release of the drug in the target tissue. HPMA copolymer conjugates with side sequences Gly-Phe-Leu-Gly cleavable by lysosomal enzymes decreased in vivo the antibody reaction by 60-85%. A comparable amount of free targeting antibody was without a significant effect. Injection of targeted daunomycin decreased the toxicity of the drug against hematopoietic precursors in bone marrow colony-forming unit-spleen 80 times compared to the same amount of free drug. The in vivo effectiveness of targeted daunomycin was confirmed morphologically. Application of free daunomycin lead to a significant irritation of Kupffer cells in liver while none of the daunomycin-antibody-copolymer conjugate had such an effect.

Protein aggregates in extracorporally perfused rabbit kidneys

Eighteen rabbit kidneys were perfused ex vivo for 1 h with allogeneic blood, and in 16 a solution of xenogeneic aggregate-free, aggregated or antibody-complexed protein was added to the perfusate 5 min after the start (human immunoglobulins or serum albumin, partly cationized, were used). The kidneys were examined by light and electron microscopy and the human and rabbit immunoglobulin (or albumin) precipitates were detected by direct immunofluorescence and ultrastructural immunohistochemistry. In 13 kidneys the perfusion produced small segmental glomerular endocapillary aggregates of platelets, leukocytes, and granular precipitates reactive with both anti-rabbit and anti-human antibodies. No typical deposits were seen in mesangium or in periphery of glomerular capillaries but rabbit Ig penetrated to the inter- and subepithelial spaces of proximal convoluted tubules. Three kidneys perfused by cationized aggregated human Ig (or by cationized albumin-antialbumin complexes) exhibited a destructive lesion with rapid breakdown of blood flow and massive global endocapillary plugs of similar ultrastructure but with focal endothelial sloughing. Pericapillary granular precipitates of human and rabbit Ig were seen in these kidneys. When the blood with cationized Ig aggregates was used for perfusion of two further kidneys extensive endocapillary aggregates with endothelial damage reappeared but the extracapillary penetration and precipitation were lacking and the blood flow largely improved. Membrane polyanion of podocytes stained by colloidal iron was preserved even in close proximity of cationized complex precipitates. Thus, in the ex-vivo perfusion model the preformed neutral aggregates did not penetrate through the glomerular capillary wall and were not phagocytized by mesangial cells. The cationized aggregates induced rapid circulatory failure with massive platelet clumping and granular pericapillary "humps" ultrastructurally different from the deposits of human and experimental immune complex glomerulonephritis.

Puromycin aminonucleoside nephropathy: ultrastructure, glomerular polyanion, and cell surface markers

Puromycin aminonucleoside nephropathy with heavy proteinuria and oedema was induced in rats by 10 consecutive daily subcutaneous injections of aminonucleoside (1.67 mg/100 g of body weight). The main ultrastructural lesions were vacuolation of podocytes and total fusion of foot processes with loss of colloidal iron-reactive polyanion layer on the epithelial surface adjacent to the basement membrane. On the other hand the outer surface of podocytes and intravacuolar granular substance stained with colloidal iron. In scanning electron microscopy of freeze-fractured tissue the swollen podocytes and the urinary spaces displayed granular and filamentous precipitates. Seven cell surface antigens were examined by indirect enzyme immunohistochemistry with a series of MRC OX monoclonal antibodies. Glomeruli of control rats exhibited rare isolated Ia- positive endocapillary cells, possibly monocytes; these elements were significantly reduced in puromycin aminonucleoside nephropathy but there was an increase in Ia- positive cells in the cortical interstitium. Control kidneys harboured scanty interstitial T lymphocytes. These latter, especially the T8- positive cytotoxic/suppressor subpopulation, were markedly augmented in puromycin aminonucleoside nephropathy. The expression of class I histocompatibility antigens and of differentiation antigens (Thy 1) was not altered by aminonucleoside.