Clinical tests and magnetic resonance imaging have limited diagnostic value for triangular fibrocartilaginous complex lesions.

INTRODUCTION: The diagnostic value of clinical tests and magnetic resonance (MR) imaging for the investigation of triangular fibrocartilaginous complex (TFCC) lesions is not clear due to a lack of clinical data. MATERIALS AND METHODS: We retrospectively analyzed 908 patients who underwent clinical tests and arthroscopy for suspected TFCC lesions at our institution. Further, MR imaging findings concerning the TFCC were gathered. We correlated clinical tests and MR imaging findings with those obtained during arthroscopy, and we calculated sensitivity, specificity, as well as positive and negative predictive values. RESULTS: In the whole cohort, the positive predictive values of all clinical tests were low, ranging from 0.53 to 0.55. The ulna grinding test had the highest sensitivity, but lowest specificity. Sensitivity and specificity of the ulnar fovea sign and magnetic resonance imaging were similar, ranging from 0.73 to 0.76, and from 0.41 to 0.44, respectively. To some degree, the diagnostic value seemed to depend on the Palmer class of TFCC lesion. CONCLUSIONS: According to this study, clinical tests and MR imaging findings are of very limited diagnostic value for the diagnosis of TFCC lesions.

How Ebola virus counters the interferon system.

Zoonotic transmission of Ebola virus (EBOV) to humans causes a severe haemorrhagic fever in afflicted individuals with high case-fatality rates. Neither vaccines nor therapeutics are at present available to combat EBOV infection, making the virus a potential threat to public health. To devise antiviral strategies, it is important to understand which components of the immune system could be effective against EBOV infection. The interferon (IFN) system constitutes a key innate defence against viral infections and prevents development of lethal disease in mice infected with EBOV strains not adapted to this host. Recent research revealed that expression of the host cell IFN-inducible transmembrane proteins 1-3 (IFITM1-3) and tetherin is induced by IFN and restricts EBOV infection, at least in cell culture model systems. IFITMs, tetherin and other effector molecules of the IFN system could thus pose a potent barrier against EBOV spread in humans. However, EBOV interferes with signalling events required for human cells to express these proteins. Here, we will review the strategies employed by EBOV to fight the IFN system, and we will discuss how IFITM proteins and tetherin inhibit EBOV infection.

The significance of conventional radiographic parameters in the diagnosis of scapholunate ligament lesions.

OBJECTIVE: Although in widespread clinical use, evidence of the diagnostic accuracy of radiographic parameters for the diagnosis of scapholunate ligament injuries is scarce. The objective of this study was to evaluate the scapholunate (SL) angle, radiolunate (RL) angle and SL gap as diagnostic parameters for these lesions. METHODS: Eight hundred forty nine patients, who underwent wrist arthroscopy at our institution because of wrist pain were included in a retrospective analysis. In all patients the SL angle, RL angle and SL gap were measured on preoperative radiographs. These parameters were correlated with the actual finding of the SL ligament during arthroscopy. Optimal test thresholds were calculated as well as sensitivity, specificity and the likelihood ratios of each parameter. RESULTS: All three parameters proved useful in statistical analysis. The optimal cut-off points for diagnosing lesions of the SL ligament were calculated as 62.5° for the SL angle, 12.5° for the RL angle and 2.5 mm for the SL gap. SL angles had the greatest specificity (0.93). CONCLUSIONS: We were able to validate plain radiographs as a reliable tool in the work-up of patients with suspected SL ligament injuries. However, wrist arthroscopy remains the gold standard in diagnosing and treating these lesions.

[Long-term treatment of refractory myasthenia gravis with immunoadsorption]. / Langzeitbehandlung der therapierefraktären Myasthenia gravis mittels Immunadsorption.

BACKGROUND AND OBJECTIVE: Myasthenia gravis in the majority of patients is a well treatable neurological autoimmune disorder with a prevalence of 60-150 per million. For the treatment of myasthenic crisis in the intensive care unit the use of therapeutic apheresis, e. g. immunoadsorption or plasma exchange, is well established due to its rapid therapeutic effect, whereas the necessity in long term treatment is still questioned. Aim of this retrospective cohort-study was the assessment of patients with refractory myasthenia gravis in Germany treated by regular immunoadsorption, the characterization of previous therapies and the efficacy of long-term treatment. PATIENT AND METHODS: In total 14 patients (9 women, 5 men, mean age: 40.5 years) were identified in Germany using regular therapeutic apheresis. 13 were treated with different modes of immunoadsorption (10 yen l-tryptophan-adsorption, 2 yen epitope-specific adsorption, 1 yen polyclonal sheep antibody on sepharose) and 1 with plasma exchange. Mean duration of standard treatment of myasthenia gravis before initiation of regular apheresis was 7.8 years. RESULTS: Average duration of analyzed apheresis treatment was 6.4 years, with a mean treatment-interval of 1.1 per week. Mean reduction rate of autoantibodies against acetylcholine-receptor-protein was 50-60 % per session. After initiation of immunoadsorption the mean time of hospitalisation decreased significantly by app. 60 %. In particular the number of myasthenic crises could be reduced by 89 % per year. Tolerability of immunoadsorption was very good, no severe adverse events occurred. CONCLUSION: In conclusion, for the treatment of the subgroup of myasthenia gravis patients becoming refractory to standard treatment immunoadsorption should be regarded as integral part of the therapeutic armamentarium to stabilize and optimize the state of neurologic rehabilitation. This evaluation should be also carefully considered by carriers of health care cost as currently best available evidence to decide on appropriate treatment regimens for these rare patients.

High-dose-rate brachytherapy for intranasal tumours in dogs: results of a pilot study.

This prospective study describes the feasibility and toxicity of (192)Iridium high-dose-rate (HDR) brachytherapy as an alternative strategy for the treatment of canine intranasal tumours. Fifteen dogs with malignant intranasal tumours were treated twice weekly using a hypofractionated protocol with eight fractions, 5 Gy per fraction, resulting in a total dose of 40 Gy. Acute and chronic adverse side-effects appeared to be rare. Only 7% of the acute side-effects and 5% of the chronic were classified as severe (grade 3). Eight dogs showed clinical complete remission, and five dogs had partial remission, with a resolution of tumour-related symptoms. Magnetic resonance imaging showed a reduced tumour mass in 12 cases. Median survival time was 17 months (range 4-48 months), with four dogs (three without disease) still alive. Median time to recurrence of these dogs was 14 months. In nine dogs, progression or recurrence of the tumour was the cause of death. This study suggests that HDR brachytherapy is feasible and well tolerated.

Participación de las personas mayores en el mercado de trabajo y en la sociedad / Participation of the elderly in the labour market and in society

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Evaluation of current approaches to inhibit HIV entry.

Highly active inhibitors of human immunodeficiency virus (HIV) reverse transcriptase and protease have made it possible to dramatically reduce virus load in HIV-positive individuals. However, the presence of viral reservoirs, the emergence of drug-resistant HIV variants and the side effects of these compounds call for research into new drugs that target different stages of the viral life cycle. One attractive target is the first step in HIV replication: entry of virus into cells. HIV entry is initiated by the attachment of the virus to the host cell membrane, which is some cases involves binding to attachment factors such as DC-SIGN. Subsequent interaction of the envelope protein (Env) with the CD4 receptor causes conformational changes that enable Env to interact with a coreceptor, generally the chemokine receptors CCR5 or CXCR4. Coreceptor engagement triggers the final conformational changes in Env, which mediate lipid mixing between the viral and cellular membranes. All of these steps are potential targets for therapeutic intervention: targeting proteins that mediate viral attachment may reduce HIV transmission, while receptor blockade will inhibit virus entry. Highly conserved domains in Env which bind to CD4 and coreceptor are promising targets for broadly neutralizing antibodies, and peptide inhibitors that bind to Env and that block membrane fusion are in advanced clinical trials. These new approaches may supplement current HIV therapy and may assist in the development of an HIV vaccine.

Placental expression of DC-SIGN may mediate intrauterine vertical transmission of HIV.

Mechanisms of transplacental transmission of human immunodeficiency virus (HIV) are poorly understood. DC-SIGN is a C-type lectin able to bind HIV gp120 with high affinity, mediating HIV adsorption to the surface of dendritic cells for up to several days. Via this mechanism, DC-SIGN significantly enhances the infection of CD4(+) co-receptor (CCR5 or CXCR4)(+) T lymphocytes in trans. In this study, DC-SIGN-specific serum was developed to investigate the cell type responsible for the high level of DC-SIGN RNA expression previously observed in the placenta. DC-SIGN expression was shown on CD68(+) HLA-II(+) CD14(low) S100(+/-) CD83(-) CD86(-) cmrf-44(-) villous cells consistent with Hofbauer cells and also on CD68(+) HLA-II(+) CD14(high) S100(-) CD83(-) CD86(-) cmrf-44(-) decidual macrophages. The DC-SIGN(+) Hofbauer cells co-express CD4 and the chemokine receptors, CCR5 and CXCR4, observations which may account for the ability of these cells to become infected with HIV. These fetal DC-SIGN(+) cells are separated by only a layer of trophoblast from both DC-SIGN(+) maternal cells and maternal blood, potential sources of HIV in infected mothers. Previous studies have suggested that this trophoblast layer is frequently breached during pregnancy. It is therefore proposed that DC-SIGN may facilitate the transplacental transmission of HIV.

Functional and antigenic characterization of human, rhesus macaque, pigtailed macaque, and murine DC-SIGN.

DC-SIGN, a type II membrane protein with a C-type lectin binding domain that is highly expressed on mucosal dendritic cells (DCs) and certain macrophages in vivo, binds to ICAM-3, ICAM-2, and human and simian immunodeficiency viruses (HIV and SIV). Virus captured by DC-SIGN can be presented to T cells, resulting in efficient virus infection, perhaps representing a mechanism by which virus can be ferried via normal DC trafficking from mucosal tissues to lymphoid organs in vivo. To develop reagents needed to characterize the expression and in vivo functions of DC-SIGN, we cloned, expressed, and analyzed rhesus macaque, pigtailed macaque, and murine DC-SIGN and made a panel of monoclonal antibodies (MAbs) to human DC-SIGN. Rhesus and pigtailed macaque DC-SIGN proteins were highly similar to human DC-SIGN and bound and transmitted HIV type 1 (HIV-1), HIV-2, and SIV to receptor-positive cells. In contrast, while competent to bind virus, murine DC-SIGN did not transmit virus to receptor-positive cells under the conditions tested. Thus, mere binding of virus to a C-type lectin does not necessarily mean that transmission will occur. The murine and macaque DC-SIGN molecules all bound ICAM-3. We mapped the determinants recognized by a panel of 16 MAbs to the repeat region, the lectin binding domain, and the extreme C terminus of DC-SIGN. One MAb was specific for DC-SIGN, failing to cross-react with DC-SIGNR. Most MAbs cross-reacted with rhesus and pigtailed macaque DC-SIGN, although none recognized murine DC-SIGN. Fifteen of the MAbs recognized DC-SIGN on DCs, with MAbs to the repeat region generally reacting most strongly. We conclude that rhesus and pigtailed macaque DC-SIGN proteins are structurally and functionally similar to human DC-SIGN and that the reagents that we have developed will make it possible to study the expression and function of this molecule in vivo.

DC-SIGN interactions with human immunodeficiency virus: virus binding and transfer are dissociable functions.

The C-type lectins DC-SIGN and DC-SIGNR capture and transfer human immunodeficiency virus (HIV) to susceptible cells, although the underlying mechanism is unclear. Here we show that DC-SIGN/DC-SIGNR-mediated HIV transmission involves dissociable binding and transfer steps, indicating that efficient virus transmission is not simply due to tethering of virus to the cell surface.

Basic amino acid residues in the V3 loop of simian immunodeficiency virus envelope alter viral coreceptor tropism and infectivity but do not allow efficient utilization of CXCR4 as entry cofactor.

In contrast to human immunodeficiency viruses type 1 and type 2 (HIV-1 and HIV-2, respectively), simian immunodeficiency virus (SIVmac) rarely uses CXCR4 (X4) for efficient entry into target cells. Basic amino acid residues in the V3 loop of HIV Env allow efficient coreceptor utilization of X4. Therefore, we investigated if similar changes in the SIVmac Env protein also mediate a coreceptor switch from CCR5 (R5) to X4. Functional analysis revealed that none of eight SIVmac variants, containing V3 regions with an overall charge between +4 and +10, efficiently utilized X4 as entry cofactor. Nonetheless, these alterations had differential effects on SIV coreceptor tropism and on Env expression levels. A single amino acid substitution of L328R, located near the tip of the V3 loop, resulted in grossly reduced Env expression levels and impaired viral infectivity. Notably, additional basic residues restored efficient Env expression and virion incorporation but not infectivity. In comparison to the L328R mutation, changes of P334K and D337K had little disruptive effects on SIVmac entry and replication. Interestingly, mutation of L320K and P321R disrupted coreceptor usage of GPR15 but not R5. These changes also impaired SIVmac replication in peripheral blood mononuclear cells (PBMC) derived from a Delta32/Delta32 donor but not in R5-expressing human or simian PBMC. Our results show that positively charged amino acid residues in the V3 loop affect SIVmac coreceptor tropism and infectivity but do not allow efficient utilization of X4.

DC-SIGN interactions with human immunodeficiency virus type 1 and 2 and simian immunodeficiency virus.

Dendritic cells (DCs) efficiently bind and transmit human immunodeficiency virus (HIV) to cocultured T cells and so may play an important role in HIV transmission. DC-SIGN, a novel C-type lectin that is expressed in DCs, has recently been shown to bind R5 HIV type 1 (HIV-1) strains and a laboratory-adapted X4 strain. To characterize the interaction of DC-SIGN with primate lentiviruses, we investigated the structural determinants of DC-SIGN required for virus binding and transmission to permissive cells. We constructed a panel of DC-SIGN mutants and established conditions which allowed comparable cell surface expression of all mutants. We found that R5, X4, and R5X4 HIV-1 isolates as well as simian immunodeficiency and HIV-2 strains bound to DC-SIGN and could be transmitted to CD4/coreceptor-positive cell types. DC-SIGN contains a single N-linked carbohydrate chain that is important for efficient cell surface expression but is not required for DC-SIGN-mediated virus binding and transmission. In contrast, C-terminal deletions removing either the lectin binding domain or the repeat region abrogated DC-SIGN function. Trypsin-EDTA treatment inhibited DC-SIGN mediated infection, indicating that virus was maintained at the surface of the DC-SIGN-expressing cells used in this study. Finally, quantitative fluorescence-activated cell sorting analysis of AU1-tagged DC-SIGN revealed that the efficiency of virus transmission was strongly affected by variations in DC-SIGN expression levels. Thus, variations in DC-SIGN expression levels on DCs could greatly affect the susceptibility of human individuals to HIV infection.

DC-SIGNR, a DC-SIGN homologue expressed in endothelial cells, binds to human and simian immunodeficiency viruses and activates infection in trans.

DC-SIGN, a C-type lectin expressed on the surface of dendritic cells (DCs), efficiently binds and transmits HIVs and simian immunodeficiency viruses to susceptible cells in trans. A DC-SIGN homologue, termed DC-SIGNR, has recently been described. Herein we show that DC-SIGNR, like DC-SIGN, can bind to multiple strains of HIV-1, HIV-2, and simian immunodeficiency virus and transmit these viruses to both T cell lines and human peripheral blood mononuclear cells. Binding of virus to DC-SIGNR was dependent on carbohydrate recognition. Immunostaining with a DC-SIGNR-specific antiserum showed that DC-SIGNR was expressed on sinusoidal endothelial cells in the liver and on endothelial cells in lymph node sinuses and placental villi. The presence of this efficient virus attachment factor on multiple endothelial cell types indicates that DC-SIGNR could play a role in the vertical transmission of primate lentiviruses, in the enabling of HIV to traverse the capillary endothelium in some organs, and in the presentation of virus to CD4-positive cells in multiple locations including lymph nodes.

Natural proteolytic processing of hemofiltrate CC chemokine 1 generates a potent CC chemokine receptor (CCR)1 and CCR5 agonist with anti-HIV properties.

Hemofiltrate CC chemokine (HCC)-1 is a recently described human chemokine that is constitutively expressed in numerous tissues and is present at high concentrations in normal plasma. Using a cell line expressing CC chemokine receptor (CCR)5 as a bioassay, we isolated from human hemofiltrate an HCC-1 variant lacking the first eight amino acids. HCC-1[9-74] was a potent agonist of CCR1, CCR3, and CCR5 and promoted calcium flux and chemotaxis of T lymphoblasts, monocytes, and eosinophils. It also blocked entry of HIV-1 strains using CCR5 as coreceptor. Limited tryptic digestion of HCC-1 generated the active variant. Conditioned media from several tumor cell lines activated HCC-1 with a high efficiency, and this activity could be inhibited by serine protease inhibitors. Our results indicate that HCC-1 represents a nonfunctional precursor that can be rapidly converted to the active chemokine by proteolytic processing. This process represents an additional mechanism by which tumor cells might generate chemoattractant molecules and recruit inflammatory cells. It might also affect HIV-1 replication in infected individuals and play an important role in AIDS pathogenesis.

Expression and coreceptor activity of STRL33/Bonzo on primary peripheral blood lymphocytes.

CCR5 and CXCR4 are the major coreceptors that mediate human immunodeficiency virus 1 (HIV-1) infection, while most simian immunodeficiency virus (SIV) isolates use CCR5. A number of alternative coreceptors can also mediate infection of some virus strains in vitro, although little is known about their in vivo relevance. Therefore, we characterized the expression pattern and coreceptor activity of one of these alternative coreceptors, STRL33/Bonzo, using a newly developed monoclonal antibody. In addition to being highly expressed (approximately 1000-7000 STRL33 ABS [antibody binding sites]) on specific subsets of natural killer cells (CD3(-)/CD16(-/low)/CD56(+) and CD3(-)/CD16(low)/CD56(-)) and CD19(+) B lymphocytes (approximately 300-5000 STRL33 ABS), STRL33 was expressed at levels sufficient to support virus infection on freshly isolated, truly naive CD4(+)/CD45RA(+)/CD62L(+) cells (6000-11 000 ABS). STRL33 expression on peripheral blood mononuclear cells (PBMCs) was increased by mitogenic stimulation (OKT3/IL-2 [interleukin-2] had a greater effect than phytohemaglutinin (PHA)/IL-2), but it was dramatically decreased upon Ficoll purification. Infection of CCR5(-) human peripheral blood lymphocytes (PBLs) showed that 2 different SIV envelope (Env) proteins mediated entry into STRL33(+) cells. More importantly, the preferential infection of STRL33(+) cells in CCR5(-) PBLs by an R5/X4/STRL33 HIV-1 maternal isolate in the presence of a potent CXCR4 antagonist (AMD3100) suggests that STRL33 can be used as a coreceptor by HIV-1 on primary cells. Rhesus macaque (rh) STRL33 was used less efficiently than human STRL33 by the majority of SIV Env proteins tested despite similar levels of expression, thereby making it less likely that STRL33 is a relevant coreceptor in the rhesus macaque system. In summary, the expression pattern and coreceptor activity of STRL33 suggest its involvement in trafficking of tumor-infiltrating lymphocytes and indicate that STRL33 may be a relevant coreceptor in vivo.

Rapid, B lymphoid-restricted engraftment mediated by a primitive bone marrow subpopulation.

Utilizing multiparameter flow cytometry, we have defined a subset of bone marrow cells containing lymphoid-restricted differentiation potential after i.v. transplantation. Bone marrow cells characterized by expression of the Sca-1 and c-kit Ags and lacking Ags of differentiating lineages were segregated into subsets based on allele-specific Thy-1.1 Ag expression. Although hematopoietic stem cells were recovered in the Thy-1.1low subset as previously described, the Thy-1.1neg subset consisted of progenitor cells that preferentially reconstituted the B lymphocyte lineage after i.v. transplantation. Recipients of Thy-1.1neg cells did not survive beyond 30 days, presumably due to the failure of erythroid and platelet lineages to recover after transplants. Thy-1.1neg cells predominantly reconstituted the bone marrow and peripheral blood of lethally irradiated recipients with B lineage cells within 2 weeks, although a low frequency of myeloid lineage cells was also detected. In contrast, myeloid progenitors outnumbered lymphoid progenitors when the Thy-1.1neg population was assayed in culture. When Thy-1. 1low stem cells were rigorously excluded from the Thy-1.1neg subset, reconstitution of T lymphocytes was rarely observed in peripheral blood after i.v. transplantation. Competitive repopulation studies showed that the B lymphoid reconstitution derived from Thy-1.1neg cells was not sustained over a 20-wk period. Therefore, the Thy-1. 1neg population defined in these studies includes transplantable, non-self-renewing B lymphocyte progenitor cells.

Simian immunodeficiency virus utilizes human and sooty mangabey but not rhesus macaque STRL33 for efficient entry.

It has been established that many simian immunodeficiency virus (SIV) isolates utilize the orphan receptors GPR15 and STRL33 about as efficiently as the chemokine receptor CCR5 for entry into target cells. Most studies were performed, however, with coreceptors of human origin. We found that SIV from captive rhesus macaques (SIVmac) can utilize both human and simian CCR5 and GPR15 with comparable efficiencies. Strikingly, however, only human STRL33 (huSTRL33), not rhesus macaque STRL33 (rhSTRL33), functioned efficiently as an entry cofactor for a variety of isolates of SIVmac and SIV from sooty mangabeys. A single amino acid substitution of S30R in huSTRL33 impaired coreceptor activity, and the reverse change in rhSTRL33 greatly increased coreceptor activity. In comparison, species-specific sequence variations in N-terminal tyrosines in STRL33 had only moderate effects on SIV entry. These results show that a serine residue located just outside of the cellular membrane in the N terminus of STRL33 is critical for SIV coreceptor function. Interestingly, STRL33 derived from sooty mangabeys, a natural host of SIV, also contained a serine at the corresponding position and was used efficiently as an entry cofactor. These results suggest that STRL33 is not a relevant coreceptor in the SIV/macaque model but may play a role in SIV replication and transmission in naturally infected sooty mangabeys.