Interleukin-1 is essential for systemic inflammatory bone loss.

OBJECTIVES: Chronic inflammation is a major risk factor for systemic bone loss leading to osteoporotic fracture and substantial morbidity and mortality. Inflammatory cytokines, particularly tumour necrosis factor (TNF) and interleukin-1 (IL1), are thought to play a key role in the pathogenesis of inflammation-induced bone loss, but their exact roles are yet to be determined. METHODS: To determine whether TNF directly triggers bone loss or requires IL1, human TNFalpha mice (hTNFtg) were crossed with mice lacking IL1alpha and IL1beta (IL1(-/-)hTNFtg). Systemic bone architecture was evaluated using CT scanning, static and dynamic bone histomorphometry and serum markers of bone metabolism. RESULTS: hTNFtg mice developed severe bone loss accompanied by a severe distortion of bone microarchitecture. Bone trabeculae were thinner and decreased in numbers, resulting in increased trabecular separation. Histomorphometric analyses revealed strongly increased bone resorption in hTNFtg mice compared with wild-type mice. In contrast, IL1(-/-)hTNFtg mice were fully protected from systemic bone loss despite still developing inflammation in their joints. Lack of IL1 completely reversed increased osteoclast formation and bone resorption in hTNFtg mice and the increased levels of RANKL in these mice. Structural parameters and osteoclast and osteoblast numbers were indistinguishable from wild-type mice. CONCLUSIONS: These data indicate that IL1 is essential for TNF-mediated bone loss. Despite TNF-mediated inflammatory arthritis, systemic bone is fully protected by the absence of IL1, which suggests that IL1 is an essential mediator of inflammatory osteopenia.

Selective p38MAPK isoform expression and activation in antineutrophil cytoplasmatic antibody-associated crescentic glomerulonephritis: role of p38MAPKalpha.

OBJECTIVE: Crescentic glomerulonephritis (crGN) is a frequent and life-threatening manifestation of antineutrophil cytoplasmatic antibody-associated vasculitis. Up-regulation of proinflammatory cytokines contributes to renal damage by activation of p38 mitogen-activated protein kinases (MAPKs). However, it is unclear which of the four p38MAPK isoforms are expressed, activated and hence of major importance in crGN. METHODS: Kidney biopsies of patients with antineutrophil cytoplasmatic antibody-positive crGN and control samples were investigated for the expression and phosphorylation of p38MAPK isoforms and downstream target kinase MAPKAP2 by immunohistochemistry. Expression and functional activation of p38MAPK isoforms by TNF was also assessed in a human podocyte cell line by reverse transcription-polymerase chain reaction, immunoblotting and kinase array. RESULTS: Strong expression of p38MAPKalpha, beta and gamma isoforms was found in glomerular podocytes and crescents. Infiltrating leucocytes showed predominant p38MAPKalpha expression. Activation of p38MAPK and its downstream mediator MAPKAP2 was found in crGN confined to glomerular podocytes, crescents and inflammatory infiltrates. Interestingly, corticosteroid treatment before kidney biopsy diminished p38MAPK activation in crGN. Activated p38MAPK co-localised with alpha, beta and gamma isoforms in podocytes and crescents, while leucocytes showed mainly p38MAPKalpha activation. In a human podocyte cell line mRNA and protein of all four p38MAPK isoforms was expressed but only p38MAPKalpha was activated upon challenge with TNF. CONCLUSIONS: This study shows selective p38MAPK isoform expression and activation in crGN. Podocytes and podocyte-induce crescent formation is the main source of p38MAPK activation in crGN. TNF is a potent and selective activator of the alpha-isoform in podocytes, which therefore appears as a main contributor to proinflammatory signalling in the glomerulum of crGN.

Characterization of the nuclear import of human MutLalpha.

DNA mismatch repair (MMR) is essential for the maintenance of replication fidelity. Its major task is to recognize mismatches as well as insertion/deletion loops of newly synthesized DNA strands. Although different players of human MMR have been identified, the regulation of essential steps of MMR is poorly understood. Because MMR is initiated in the nucleus, nuclear import might be a mechanism to regulate MMR. Nuclear targeting is accomplished by conserved signal sequences called nuclear localization signals (NLS), which represent clusters of positively charged amino acids (aa). hMLH1 contains two clusters of positively charged amino acids, which are candidate NLS sequences (aa 469-472 and 496-499), while hPMS2 contains one (aa 574-580). To study the effect of these clusters on nuclear import, NLS mutants of hMLH1 and hPMS2 were generated and expressed in 293T cells. The subcellular localization of the mutant constructs was monitored by confocal laser microscopy. We demonstrated that missense mutations of two signal sequences, one in hMLH1 and one in hPMS2, lead to impaired nuclear import, which was especially prominent for mutants of the hMLH1 residues K471 and R472; and hPMS2 residues K577 and R578.

Apoptosis regulators and their role in tumorigenesis.

It has become clear that, together with deregulated growth, inhibition of programmed cell death (PCD) plays a pivotal role in tumorigenesis. In this review, we present an overview of the genes and mechanisms involved in PCD. We then summarize the evidence that impaired PCD is a prerequisite for tumorigenesis, as indicated by the fact that more and more neoplastic mutations appear to act by interfering with PCD. This has made the idea of restoration of corrupted 'death programs' an intriguing new area for potential cancer therapy.

An improved procedure for the generation of recombinant single-chain Fv antibody fragments reacting with human CD13 on intact cells.

A procedure was developed to generate recombinant single chain Fv (scFv) antibody fragments reacting with the extracellular domain of human cell surface antigen CD13 (hCD13; aminopeptidase N) on intact cells. Membrane fractions prepared from a stably transfected hCD13-positive murine NIH/3T3 cell line were used to immunize BALB/c mice, with the intention that hCD13 would be the major immunogenic molecule recognized by the immune system. Spleen RNA from the immunized mice served to generate a combinatorial scFv phage display library. The library was adsorbed against non-transfected NIH/3T3 or Sf21 insect cells to eliminate nonrelevant binders. The supernatant was then used for panning with either hCD13-transfected Sf21 insect cells or a hCD13-expressing human leukemia-derived cell line. Therefore, the key concepts of the procedure were the presentation of hCD13 as the sole human antigen on murine NIH/3T3 cells and a screening strategy where hCD13 was the major common antigen of the material used for immunization and panning. Two different hCD13-reactive phages were isolated and the soluble scFvs were expressed in E. coli and purified. The two scFvs, anti-hCD13-1 and anti-hCD13-3, differed at four amino acid positions in their V(H) regions and both had high affinities for hCD13 as determined by surface plasmon resonance (K(D)=7 and 33x10(-10) M, respectively). Both efficiently recognized hCD13 on intact cells. Therefore, the procedure allowed the production of high affinity scFvs reacting with a desired antigen in its native conformation without requiring extensive purification of the antigen and should be useful for the preparation of scFvs against other conformation-sensitive cell-surface antigens.

Gp130 and ras mediated signaling in human plasma cell line INA-6: a cytokine-regulated tumor model for plasmacytoma.

INTRODUCTION: Cytokines of the gp130-family, particularly interleukin(IL)-6, play a crucial role in the propagation of malignant plasma cells. MATERIALS AND METHODS: The role of IL-6 and other gp130-cytokines was studied in the human plasma cell line INA-6 in vitro and in INA-6 xenografts. The proliferative response to gp130-cytokines was evaluated and activated components of gp130-signaling pathways were identified by Western blotting and DNA binding studies. Specifically, expression of IL-6 and receptors for IL-6 and leukemia inhibitory factor were analysed by RT-PCR and ELISA. RESULTS: The plasma cell line INA-6 was cultured for several years remaining strictly dependent on exogenous IL-6. Other gp130-cytokines had no significant effect on INA-6 cell proliferation in vitro. Due to an activating mutation in the N-ras gene, mitogen-activated protein kinases (MAPK) were constitutively phosphorylated. In contrast, signal transducer and activator of transcription(STAT)-3 activation was dependent on stimulation with IL-6. Blocking of either one of these pathways resulted in a significant decrease of INA-6 cell proliferation. Remarkably, INA-6 xenografts did not require exogeneous IL-6 for proliferation in vivo. Instead, an autocrine IL-6 loop and, in certain tumor sublines, responsiveness to additional gp130-cytokines was induced during in vivo growth. CONCLUSION: Activation of the gp130 signal transducer is mandatory for INA-6 cell growth in vitro and in vivo. Both the MAPK and the Jak/STAT pathway are operative in malignant plasma cells and either one is essential for plasma cell growth. The INA-6 cell line provides a preclinical model to study growth regulation of human plasmacytoma cells and to evaluate novel therapeutic strategies.

A novel protein (Fbf-1) that binds to CD95/APO-1/FAS and shows sequence similarity to trichohyalin and plectin.

The Fas/Apo-1/CD95 cell surface receptor belongs to the TNF receptor family of cell death inducing molecules. A number of cytosolic adapter proteins that mediate signal transduction of CD95 have been characterized, but some features of the molecular mechanisms of CD95-induced cell death remain elusive. We describe here a novel protein that can interact with the cytosolic domain of the murine CD95 receptor in a yeast two-hybrid assay. This novel protein was termed Fbf-1 for Fas binding factor and bears no sequence similarity to the known CD95 adapter proteins. Fbf-1 is 1173 aa long and has a theoretical molecular weight of around 130 kDa. The protein is expressed in a wide variety of tissues and is localized in the cytoplasm. Fbf-1 is a very hydrophilic protein, highly conserved between mouse and human and bears a carboxyterminal leucine heptad repeat reminiscent of leucine zipper protein interaction domains. In addition, it shows sequence similarity to trichohyalin and plectin pointing to a function as a structural protein.

Therapy with CD7 monoclonal antibody TH-69 is highly effective for xenografted human T-cell ALL.

Human T-cell acute lymphocytic leukaemia (ALL) was established in athymic nude or severe combined immunodeficient (SCID) mice by injecting CEM or MOLT-16 cells. When nude mice bearing approx. 2 g of tumour were treated with a single injection of CD7 antibody TH-69, 82.6% reached complete remission within 10 d whereas 13.0% showed partial remission. Similarly, in SCID mice with advanced disease a significant prolongation of survival was seen. The therapeutic effects were dependent upon dose and affinity of the antibody. TH-69 is a high-affinity antibody (7.6 x 10(9) M-1) that rapidly induced modulation during treatment. The Fc-portion of the antibody was required for effective tumour cell killing. Complement deposition was found on tumour sections after TH-69 treatment and in part may account for tumour destruction. There was no evidence for antibody-dependent cellular cytotoxicity (ADCC). The kinetics of tumour disappearance suggested the initiation of a programmed cell death (PCD), despite the lack of significant DNA fragmentation. Unmodified high-affinity antibodies to the T-cell antigen CD7 have potential for T-cell ALL therapy.

[Intensive care problems in congenital polycystic lung abnormality]. / Intensivtherapeutische Probleme bei angeborener polyzystischer Lungenfehlbildung.

The development of bilateral tension cysts in a 6-month-old child suffering from inborn honeycomb lung resulted in acute cardiorespiratory insufficiency. First of all, we succeeded in controlling the recurrent rises in intrathoracic pressure by puncturing and chest draining performed by suction and by the Bülau method. The child thus became fit to be operated on. The right lower lobe, and, 7 days later, the left upper lobe, were resected and multiple single cysts excised from both residual lungs. The postoperative course of the disease was not free from complications, but five years of follow-up showed that the child's general development had become normal. Possibilities of treatment of pulmonary insufficiency, a typical symptom of polycystic lung malformation, are discussed, and the necessity for an early operation is emphasised.

[Treatment of postoperative pulmonary insufficiency in newborn with congenital diaphragmatic hernia]. / Zur Behandlung der postoperativen Ateminsuffizienz bei Neugeborenen mit kongenitalem Zwerchfelldefekt.

Treatment of postoperative pulmonary insufficiency in congenital diaphragmatic hernia has two aims: on the one hand, it serves to assist in achieving full pulmonary development, whereas on the other hand it aims at lowering pulmonary hypertension. Full development of the hypoplastic lung is the decisively important factor with regard to improving ventilation and perfusion. The same degree of importance is attached to correcting hypoxia as well as acidosis. The different performance of the lungs in respect of mechanics of breathing can be influenced most effectively by a well-balanced application of several measures exercising an influence on pulmonary pressure, such as positive ventilatory pressure and thoracic suction drainage. If these measures are unsuccessful and in case of a clinically relevant ductal right-left shunt, it is recommended to administer vasodilators; in exceptional cases, ductal ligature can be the procedure of choice. These therapeutic problems are discussed on the basis of an evaluation of the authors' own patients treated between 1976 and 1980 (10 cases).

Spontaneous retroperitoneal hemorrhage: a diagnostic challenge.

Spontaneous retroperitoneal hemorrhage can present a difficult diagnostic dilemma. We present 4 illustrative cases within the last 2 years at our institutions. Excluding traumatic injury to the retroperitoneum and abdominal aortic aneurysms, about 75 per cent of the cases are related to neoplasms or vascular anomalies. An awareness of predisposing disease states is important. A high index of suspicion and an aggressive diagnostic approach are necessary. If evaluation does not disclose an etiology for retroperitoneal hemorrhage then non-operative management may be considered. This is especially true if an underlying systemic condition is present.

[Treatment of chronic infantile hepatitis with D-penicillamine (author's transl)]. / Die Behandlung der chronischen kindlichen Hepatitis mit D-Penicillamin.

Detailed discussion of action, indication and side effects of D-Penicillamine which was used for the treatment of chronic hepatitis of infancy. Of 18 patients, 7 had chronic-active hepatitis, 6 chronic persisting hepatitis, 2 subacute hepatitis and 3 fibrosis of the liver. Control of results was based on numerous clinical chemical investigations and repeated liver biopsies. The transaminases and histology of the biopsies were the essential parameters. Doses between 15 and 35 mg/kg of body weight gave very favorable results in these 18 patients, treated over 5 to 24 months. Australia antigen-negative, chronic active hepatitis appeared to be particularly suited for this type of treatment.