Association of oxidative stress with postmenopausal osteoporosis and the effects of hydrogen peroxide on osteoclast formation in human bone marrow cell cultures

It has been suggested that oxidative stress is associated with the pathogenesis of osteoporosis. The objective of this study was to explore the association between a marker of oxidative stress and either bone turnover markers or bone mineral density (BMD) in postmenopausal women. In addition, the effects of oxidative stress on the formation of osteoclasts in human bone marrow cell culture were examined. We performed a cross-sectional analysis in healthy postmenopausal women aged 60-78 years (n = 135, 68.2 +/- 4.9). Oxidative stress was evaluated in the serum by measuring 8-hydroxy-2'-deoxyguanosine (8-OH-dG) levels. The biochemical markers of bone turnover and areal BMD were measured in all participants. Multivariate linear regression analysis revealed a negative association between 8-OH-dG levels and BMD of the lumbar spine, total hip, femoral neck, and trochanter and positive association with type I collagen C-telopeptide (ICTP) levels. The odds ratio of 8-OH-dG for osteoporosis was 1.54 (1.14-2.31, P = 0.003). In cultures of primary human marrow cells, H2O2 caused concentration-dependent activation of TRAP-positive multinucleated giant cells. H2O2 also increased the area of pits per osteoclast activity assay substrate. RT-PCR showed that H2O2 stimulated the expression of M-CSF and RANKL and increased the RANKL/OPG ratio. The data support the view that oxidative stress is associated with increased bone resorption and low bone mass in otherwise healthy women. In addition, RANKL and M-CSF stimulation induced by oxidative stress may participate in osteoclastogenesis in human bone.

The significance of florid giant cell component in renal cell carcinoma: a case report and review of the literature

BACKGROUND

Renal cell carcinoma (RCC) with multinucleated giant cells has been reported in the literature. Different types of multinucleated giant cells have been described, including the osteoclast-like giant cells, rhabdoid cells, syncytial giant cells and tumor multinucleated giant cells.

RESULTS

We describe a unique case of a clear cell RCC with extensive giant cell component. Tumor giant cells were arranged in an alveolar pattern and formed more than 50% of the tumor. The rest of the tumor was a classic clear cell renal cell carcinoma. A rhabdoid component was also focally seen. The immunohistochemical profile of the giant cells showed positivity for RCC, vimentin and, very focal positivity for cytokeratins, and negatively for CD68. A traditional spindle cell sarcomatoid component was not seen. The patient had advanced disease at presentation with metastasis to peri-aortic lymph nodes.

CONCLUSION

Giant cells can rarely constitute a major component of renal cell carcinoma and it is not clear if these represent a sarcomatoid component or merely a higher grade of the epithelial component. These cells may have different immunohistochemical profiles in different cases and may therefore be of different derivation. This may necessitate the revision of current classification schemes for renal cell carcinoma. It is also not clear how the presence of the various types of giant cells in renal cell carcinoma and their amount affects the clinical outcome.

[Transthoracic echocardiographic assessment of a biventricular assist device]

We present the results of standard transthoracic echocardiographic assessment of a biventricular assist device implanted in a patient with progressive heart failure caused by acute giant-cell myocarditis.

HHV-6A in syncytial giant-cell hepatitis

Syncytial giant-cell hepatitis is a rare but severe form of hepatitis that is associated with autoimmune diseases, drug reactions, and viral infections. We used serologic, molecular, and immunohistochemical methods to search for an infectious cause in a case of syncytial giant-cell hepatitis that developed in a liver-transplant recipient who had latent infection with variant B of human herpesvirus 6 (HHV-6B) and who had received the organ from a donor with variant A latent infection (HHV-6A). At the onset of the disease, the detection of HHV-6A (but not HHV-6B) DNA in plasma, in affected liver tissue, and in single micromanipulated syncytial giant cells with the use of two different polymerase-chain-reaction (PCR) assays indicated the presence of active HHV-6A infection in the patient. Expression of the HHV-6A-specific early protein, p41/38, but not of the HHV-6B-specific late protein, p101, was demonstrated only in liver syncytial giant cells in the absence of other infectious pathogens. The same markers of HHV-6A active infection were documented in serial follow-up samples from the patient and disappeared only at the resolution of syncytial giant-cell hepatitis. Neither HHV-6B DNA nor late protein was identified in the same follow-up samples from the patient. Thus, HHV-6A may be a cause of syncytial giant-cell hepatitis.

[Follicular dendritic cell sarcoma: a clinicopathologic study of 8 cases]

OBJECTIVE

To investigate clinicopathologic features, immunophenotypes and differential diagnoses of follicular dendritic cell sarcoma/tumor (FDCS).

METHODS

Eight cases of FDCS were studied using histological and immunohistochemical examinations and EBER in situ hybridization, with a review of the related literatures.

RESULTS

There were 5 male and 3 female patients with a median age of 50 years. The sites of involvement included lymph node (4 cases), tonsil, nasopharynx, liver, and spleen (1 case each, respectively). The predominant microscopic features histologically included storiform, fascicular, diffuse, whorled and nodular in patterns. The neoplastic cells, dispersed by the infiltrated small lymphocytes, were characterized by abundant eosinophilic or fine granular cytoplasm with indistinct cell borders, and syncytial in appearance. The nuclei of the tumors were ovoid, round to spindled in shape with vesicular or stippled chromatin and small distinct nucleoli. Mitotic figures varied among cases. Pseudovascular spaces and perivascular cuffing were observed in some cases. One case of FDCS involving lesion in liver showed a background of abundant lymphocytes mixing with dispersed spindle or ovoid neoplastic cells having delicate chromatin, mild nuclear atypia, irregular/vesicular nuclei and distinct nucleoli. The neoplastic cells were positive for CD21, CD35, clusterin, and weakly positive for CD68, EMA, S-100 and EGFR. Ki-67 stain showed a variable expression among cases. EBER was positive in 2 cases.

CONCLUSIONS

FDCS is a rare malignant tumor with a tendency to relapse and metastasis. Combined morphological and immunophenotypical analysis is necessary to reach a correct diagnosis.

Characterization of two distinct phospholipase C enzymes from Burkholderia pseudomallei

Burkholderia pseudomallei is a serious bacterial pathogen that can cause a lethal infection in humans known as melioidosis. In this study two of its phospholipase C (PLC) enzymes (Plc-1 and Plc-2) were characterized. Starting with a virulent strain, two single mutants were constructed, each with one plc gene inactivated, and one double mutant with both plc genes inactivated. The single plc mutants exhibited decreased extracellular PLC activity in comparison to the wild-type strain, thereby demonstrating that the two genes encoded functional extracellular PLCs. Growth comparisons between the wild-type and PLC mutants in egg-yolk-supplemented medium indicated that both PLCs contributed to egg-yolk phospholipid utilization. Both PLCs hydrolysed phosphatidylcholine and sphingomyelin but neither was haemolytic for human erythrocytes. Experimental infections of eukaryotic cells demonstrated that Plc-1 itself had no effect on plaque-forming efficiency but it had an additive effect on increasing the efficiency of Plc-2 to form plaques. Only Plc-2 had a significant role in host cell cytotoxicity. In contrast, neither Plc-1 nor Plc-2 appeared to play any role in multinucleated giant cell (MNGC) formation or induction of apoptotic death in the cells studied. These data suggested that PLCs contribute, at least in part, to B. pseudomallei virulence and support the view that Plc-1 and Plc-2 are not redundant virulence factors.

Delivery of macromolecules to plant parasitic nematodes using a tobacco rattle virus vector

Plant parasitic nematodes cause significant damage to crops on a worldwide scale. These nematodes are often soil dwelling but rely on plants for food and to sustain them during reproduction. Complex interactions occur between plants and nematodes during the nematode life cycle with plant roots developing specialized feeding structures through which nematodes withdraw nutrients. Here we describe a novel method for delivering macromolecules to feeding nematodes using a virus-based vector [tobacco rattle virus (TRV)]. We show that the parasitic nematode Heterodera schachtii will ingest fluorescent proteins transiently expressed in plant roots infected with a TRV construct carrying the appropriate protein sequence. A prerequisite for this delivery is the presence of replicating virus in root tips prior to the formation of nematode-induced syncytia. We show also that TRV vectors expressing nematode gene sequences can be used to induce RNAi in the feeding nematodes.

Lung involvement in childhood measles: severe immune dysfunction revealed by quantitative immunohistochemistry

Measles, accounting for nearly 1 million deaths each year, presents intense involvement of lymphoid organs and the lungs. The immune response in situ in the lungs was determined in blocks recovered from 42 necropsies of children who died from measles determined by immune cell phenotype (CD4, CD8, CD20, CD45RO, CD68, natural killer [NK], and antigen S-100 B [S100]) and cytokine production (interferon, tumor necrosis factor, interleukin [IL]-1, IL-2, IL-4, IL-10, and IL-12). Compared with the lungs of age-paired controls, patients with measles presented severe depletion of CD4+, CD20+, CD68+, NK+, and S100+ cells in alveolus- and bronchus-associated lymphoid tissue without depletion of CD8+ cells. Most of these features were similar in both forms of measles lung involvement, Hecht giant cell, or interstitial pneumonia, but S100+ cells were depleted in bronchus-associated lymphoid tissue from patients with Hecht pneumonia, which also occurs more frequently in malnourished children. IL-10- and IL-12-producing cells were depleted in patients with measles, whereas IL-1-, interferon-, and IL-4-producing cells were more frequently seen in the alveolus of patients with measles compared with controls. Quantitative in situ immune cell phenotype and function in the lung in measles demonstrated severe immune dysfunction, with loss of key cells, such as dendritic, CD4+, and NK+ cells, and deficient cytokine production, which allows for a better comprehension of local reactions in this process.

Absence of N-linked glycans from the F2 subunit of the major baculovirus envelope fusion protein F enhances fusogenicity

The F protein is the major glycoprotein present in the envelopes of budded virus (BV) of members of the family Baculoviridae. The F protein mediates low-pH-activated fusion with insect cell membranes. Baculovirus F proteins are synthesized as a precursor (F(0)) and cleaved post-translationally into two disulfide-bonded subunits, F(1) (C-terminal, large subunit) and F(2) (N-terminal, small subunit). Recently, N-linked glycosylation of the F(1) and F(2) subunits of Helicoverpa armigera nucleopolyhedrovirus (HearNPV) was demonstrated [Long, G., Westenberg, M., Wang, H., Vlak, J. M. & Hu, Z. (2006). J Gen Virol 87, 839-846]. Sequence analysis frequently predicts that one or more N-linked glycosylation sites are present in the F(2) subunit of baculovirus F proteins. N-glycans on envelope fusion proteins are usually required for proper conformational integrity and biological function, such as infectivity. This study examined the importance of N-linked glycosylation of the F(2) subunit of HearNPV by site-directed mutagenesis. The only putative N-linked glycosylation site in F(2) was eliminated by mutating asparagine (N(104)) to glutamine (Q), resulting in the mutant HearNPV(fN104Q). When inserted into an f-null HearNPV and a gp64-null bacmid of Autographa californica multiple nucleopolyhedrovirus, infectious BV could be retrieved that contained unglycosylated F(2). The virulence of HearNPV(fN104Q) was enhanced, as BV was produced earlier after infection and yielded larger plaques than f-null HearNPV repaired with the wild-type f gene. HearNPV(fN104Q) BV also induced much more efficient low-pH-activated syncytium formation. These results indicate that N-linked glycosylation of the HearNPV baculovirus F(2) subunit is not essential for viral infectivity and suggest that it is involved in BV production and fusogenicity.

Inhibition of henipavirus infection by Nipah virus attachment glycoprotein occurs without cell-surface downregulation of ephrin-B2 or ephrin-B3

Nipah virus (NiV) and Hendra virus (HeV) are newly identified members of the family Paramyxoviridae and have been classified in the new genus Henipavirus based on unique genetic characteristics distinct from other paramyxoviruses. Transgenic cell lines were generated that expressed either the attachment protein (G) or the fusion protein (F) of NiV. Functional expression of NiV F and G was verified by complementation with the corresponding glycoprotein, which resulted in the development of syncytia. When exposed to NiV and HeV, expression of NiV G in Crandall feline kidney cells resulted in a qualitative inhibition of both cytopathic effect (CPE) and cell death by both viruses. RT-PCR analysis of surviving exposed cells showed a complete absence of viral positive-sense mRNA and genomic negative-sense viral RNA. Cells expressing NiV G were also unable to fuse with cells co-expressing NiV F and G in a fluorescent fusion inhibition assay. Cell-surface staining for the cellular receptors for NiV and HeV (ephrin-B2 and ephrin-B3) indicated that they were located on the surface of cells, regardless of NiV G expression or infection by NiV. These results indicated that viral interference can be established for henipaviruses and requires only the expression of the attachment protein, G. Furthermore, it was found that this interference probably occurs at the level of virus entry, as fusion was not observed in cells expressing NiV G. Finally, expression of NiV G by either transient transfection or NiV infection did not alter the cell-surface levels of the two known viral receptors.

Expression of cathepsin P mRNA, protein and activity in the rat choriocarcinoma cell line, Rcho-1, during giant cell transformation

Lysosomal proteases perform critical functions in protein turnover and are essential for normal growth and development. Cathepsin P is a member of a newly discovered family of lysosomal cysteine proteases uniquely expressed in rodent placenta (PECs), and is closely related to human cathepsin L. Using the rat choriocarcinoma cell line model, Rcho-1, mRNA for the PECs cathepsins P, M, Q, R, 1, 2 was found to increase in expression during differentiation into a trophoblast giant cell phenotype. By contrast, expression of cathepsin L was not regulated. A specific enzyme assay was developed to show that activity of cathepsin P mirrored mRNA expression during differentiation. Cathepsin P protein co-localizes with cathepsin B, indicating that the enzyme probably functions in the endosomal-lysosomal compartment. This study demonstrates that the PEC genes produce functional proteases that can perform specific placental roles that are probably performed by broader specificity proteases in human placenta.

The proteome of the developing tooth of the sea urchin,Lytechinus variegatus: mortalin is a constituent of the developing cell syncytium

Echinoderm teeth are continuously growing calcite-mineralized tissues of complex structure. Two features are of special interest: (1) cell division takes place in a restricted aboral domain, the plumula, and the cells immediately merge into multinucleated syncytial layers; (2) the major part of the heavily mineralized tooth elongates and moves towards the adoral incisal tip continuously as the syncytial cells actively expand the syncytium and intermembrane mineral phase. As the first step to understanding the nature of the mineralization processes, we have isolated the proteins of the plumula and of the mature mineralized portions of the tooth, and begun their characterization. Peptide sequences were used to screen a plumula cDNA library by polymerase chain reaction. One primer set yielded a prominent amplified product which was cloned, and sequenced. Comparison with the nucleotide and protein data banks revealed the protein to be Mortalin, a member of the hsp-70 family, with >75% of its sequences identical to that of human mortalin. Immunocytochemical localization of mortalin within the plumula, using Anti-human Grp75, showed staining of the odontoblast cytosol and matrix at the point where syncytial formation was occurring. The cytosol of the syncytial layers was weakly stained. The nuclei within the syncytia were stained at their periphery. In the mature part of the tooth, the perinuclear staining of the nuclei was more prominent. We conclude that mortalin is involved in syncytium formation and maintenance. The urchin mortalin has a distinctive aspartic acid and serine-rich C-terminal domain that may link it to the mineralization process.

The use of a syncytium model of the crystalline lens of the eye as a new tool to study the light flashes phenomenon seen by astronauts

A syncytium model to study some electrical properties of the eye is proposed to study the phenomenon of anomalous light flashes (LF) perceived by astronauts in orbit. The crystalline lens is modelled as an ellipsoidal syncytium with a variable relative dielectric constant. The corresponding mathematical model is a boundary value problem for a system of two coupled elliptic partial differential equations in the two unknown syncytial electrical potentials. A numerical method to compute an approximate solution of this mathematical model is used, and some numerical results are shown. The model can be regarded as a new tool to study the LF phenomenon. In particular, the energy lost in the syncytium by a transversing cosmic charged particle is calculated and the results obtained with the syncytium model are compared with those obtained using the previously available Geant 3.21 simulation program. In addition, the interaction of antimatter-syncytium is studied, and the Creme96 computer program is used to evaluate the cosmic ray fluxes encountered by the International Space Station in its standard mission.

Giant cell interstitial pneumonia associated with nitrofurantoin

A case of giant cell interstitial pneumonia (GIF) that occurred in association with exposure to nitrofurantoin is presented. While the diagnosis of GIP is confirmed by histopathology, this diagnosis can be supported by the findings of bizarre multinucleated giant cells (MGC), elevated T lymphocytes, and a low T lymphocyte helper/suppressor ratio in the bronchoalveolar lavage fluid (BALF). Recognition of GIP as a rare manifestation of nitrofurantoin toxicity is important because prompt therapy may be associated with a favorable outcome.

Identification of Amino Acid Residues Involved in the Interaction between Measles Virus Haemagglutin (MVH) and Its Human Cell Receptor(Signaling Lymphocyte Activation Molecule, SLAM)

Signaling lymphocyte activation molecule (SLAM; also known as CD150) is a newly identified cellular receptor for measles virus (MV). The interaction between MV Haemagglutin (MVH) and SLAM is an initial step for MV entry. We have identified several novel SLAM binding sites at residues S429, T436 and H437 of MVH protein and MVH mutants in these residues dramatically decrease the ability to interaction with the cell surface SLAM and fail to coprecipitation with SLAM in vivo as well as malfunction in syncytium formation. At the same time, K58, S59 and H61 of SLAM was also identified to be critical for MVH and SLAM binding. Further, these residues may be useful targets for the development of measles therapy.

Cherubism: a clinical, radiographic, and histopathologic comparison of 7 cases

PURPOSE

Cherubism is an uncommon fibro-osseous disorder of the jaws that presents with varying degrees of involvement and a tendency toward spontaneous remission. Lesions are characterized by replacement of bone with fibrovascular tissue containing abundant multinucleated giant cells. We attempted to study the relationships among the degree of cherubism, the radiographic extent of the jaw lesions, the histopathologic findings, and the clinical course of 7 patients.

PATIENTS AND METHODS

In 7 patients diagnosed with cherubism, we evaluated the degree of fibrosis and perivascular cuffing, the presence of focal hemosiderin deposits, and giant multinucleated cell density (absent, few, moderate, or severe). Clinical course and progression were also assessed using a 4-point scale (improvement, no changes, modest progression, and marked progression).

RESULTS

The patients were followed up for an average of 8.5 years. Two patients exhibited clinical and radiographic improvement, while 3 showed no changes, and 2 progressed despite surgical treatment in 1 of them.

CONCLUSION

The course of cherubism in 1 of our patients may represent evidence of an association between the presence of abundant multinucleated giant cells, an increased extent of the lesions, and a more aggressive behavior of the disease.

[Giant cell interstitial pneumonia: a case report and literature review]

OBJECTIVE

To highlight the characteristics of giant cell interstitial pneumonia (GIP).

METHODS

The clinical, radiological and pathological data of a patient with GIP confirmed by open lung biopsy were presented, and relevant literatures were reviewed.

RESULTS

Patients with GIP usually had a history of exposure to metal dust. Clinical presentations include cough and dyspnea on exertion, and pulmonary function testing showed a restrictive abnormality. On chest radiography and high-resolution CT scans, it presents as bilateral areas of ground-glass attenuation, areas of consolidation, diffuse small nodules, extensive reticular opacities and traction bronchiectasis. The main pathological findings include a desquamative interstitial pneumonia (DIP)-like reaction with intra-alveolar macrophages and numerous large multinucleated histiocytes that ingested inflammatory cells were admixed with macrophages. The finding of GIP is almost pathognomonic for hard metal pneumoconiosis.

CONCLUSIONS

GIP is a very rare chronic interstitial pneumonia, and has no characteristic clinical manifestations. Radiographic findings are similar to other idiopathic interstitial pneumonias. Meticulous history taking on occupational exposure is important for the diagnosis of GIP.