TCR-Vbeta usage in the thymus and blood of myasthenia gravis patients

In myasthenia gravis (MG) the muscle acetylcholine receptor (AChR) is the target of an autoimmune response. The anti-AChR response may originate in the thymus, which is abnormal in most MG patients and contains anti-AChR T and B cells. Microbial superantigens (sAg) may trigger autoimmune responses and in this study we sought clues as to whether sAg play a role in the pathogenesis of MG. We investigated the frequency of use of the different TCR Vbeta families by the thymus and blood T cells in MG patients and in control subjects, using a multi-primer PCR assay. Identical TCR-Vbeta usage was found in the thymi of MG patients and controls, except Vbeta2, which showed a small increase in MG patients' thymi. Blood T cells of MG patients used Vbeta4, Vbeta6, Vbeta15, Vbeta16 and Vbeta24 significantly more than those of the controls. Vbeta4 and Vbeta6 are the gene families most frequently used by anti-AChR CD4(+) cells in MG patients. Blood T cells from MG patients used Vbeta12, Vbeta14, Vbeta17 and Vbeta18 significantly less than controls. MG patients used Vbeta4 and Vbeta6 significantly more in the blood than in the thymus, while the opposite occurred for Vbeta7, Vbeta12 and Vbeta14. Controls used Vbeta17 more and Vbeta24 less in the blood than in the thymus. The preferential expansion of Vbeta4 and Vbeta6 in MG patients might reflect the immunodominance of certain AChR epitopes, or the action of a sAg outside the thymus. The minimal differences in the TCR-Vbeta usage in the blood and thymus of control subjects might be due to expansion of T cell clones specific for common antigens. Identical Vbeta usage in the thymi of MG patients and controls does not support an important role of the thymus as the location of anti-AChR sensitization when MG is clinically evident. The differences observed in the Vbeta usage in blood and thymi of MG patients are likely to be due to preferential Vbeta usage by the anti-AChR T cells in the blood.     

CNBr/formic acid reactions of methionine- and trifluoromethionine-containing lambda lysozyme: probing chemical and positional reactivity and formylation side reactions by mass spectrometry

The cyanogen bromide (CNBr)/formic acid cleavage reactions of wild-type and trifluoromethionine (TFM)-containing recombinant lambda lysozyme were studied utilizing ESI and MALDI mass spectrometry. Detailed analysis of the mass spectra of reverse-phase HPLC-purified cleavage fragments produced from treatment of the wild-type and labeled proteins with CNBr indicated cleavage solely of methionyl peptide bonds with no observation of cleavage at TFM. N-Acetyl-TFM was also found to be resistant to reaction with CNBr, in contrast to N-acetyl-methionine. The analysis also indicated differential reactivity among the three methionine positions in the wild-type enzyme. Additionally, formylation of intact enzyme as well as peptide fragments were observed and characterized and indicated that serine, threonine, as well as C-terminal homoserine side chains are partially formylated under standard cleavage protocols.     

The association between child maltreatment and disabilities in a hospital-based epidemiological study

OBJECTIVE: Circumstances of maltreatment and the presence of disabilities. METHOD: An electronic merger of the records of all pediatric patients. RESULTS: Detailed record analysis of circumstances of maltreatment and the presence of disabilities. CONCLUSIONS: Differences between the Hospital and Residential samples, maltreatment and perpetrator characteristics, disability/maltreatment relationships, and their implications for primary health care are discussed.     

An economic evaluation of patch testing in the diagnosis and management of allergic contact dermatitis

AIM: To investigate the value of RNA detection by nucleic acid sequence based amplification (NASBA) for the monitoring of Chlamydia trachomatis infections after antibiotic treatment. METHODS: Cervical smears (n = 97) and urine specimens (n = 61) from 25 C trachomatis positive female patients were analysed for the presence of C trachomatis 16S ribosomal RNA (rRNA) by NASBA and C trachomatis plasmid DNA by the polymerase chain reaction (PCR) before and up to five weeks after antibiotic treatment. RESULTS: Chlamydia trachomatis RNA was found in all cervical smears taken before antibiotic treatment (n = 24) and in two smears taken one week after antibiotic treatment; no C trachomatis RNA was detected after two weeks or more. In contrast, C trachomatis DNA was found in all such specimens before treatment, and 21 of 25, six of 21, and five of 20 smears were found to be positive at one, two, and three weeks after treatment, respectively. After four weeks, only one of six smears was positive, and this smear had been negative in the two preceding weeks. Of the 61 urine samples investigated, C trachomatis DNA and C trachomatis RNA were found in all before treatment (n = 15), whereas one week after treatment four of 15 were C trachomatis DNA positive and C trachomatis RNA was detected in one sample only. CONCLUSIONS: These data show that RNA detection by NASBA can be used successfully to monitor C trachomatis infections after antibiotic treatment. Furthermore, it might be possible to use urine specimens as a test of cure because neither C. trachomatis DNA or RNA could be detected two weeks or more after treatment.     

Detection of thrombotic cuspal obstruction of an aortic bioprosthesis with transesophageal echocardiography

Bioprosthetic thrombotic obstruction is a rare complication which occurs relatively early after implantation. We present the transesophageal echocardiographic findings in a case of cuspal thrombosis of a Hancock aortic prosthesis which required valve replacement.     

High-density lipoprotein-binding protein (HBP)/vigilin is expressed in human atherosclerotic lesions and colocalizes with apolipoprotein E

Human extracellular superoxide dismutase (hEC-SOD) is a secreted tetrameric protein involved in protection against oxygen free radicals. Because EC-SOD is too large a protein for structural determination by multidimensional NMR, and attempts to crystallize the protein for X-ray structural determination have failed, the three-dimensional structure of hEC-SOD is unknown. This means that alternative strategies for structural studies are needed. The N-terminal domain of EC-SOD has already been studied using the fusion protein FusNN, comprised of the 49 N-terminal amino acids from hEC-SOD fused to human carbonic anhydrase (HCAII). The N-terminal domain in this fusion protein forms a well-defined three-dimensional structure, which probably contains alpha-helical elements and is responsible for the tetramerization of the protein. In this work, we have extended the studies, using site-directed mutagenesis in combination with size-exclusion chromatography, CD, and fluorescence spectroscopy, to investigate the nature of the tetrameric interaction. Our results show that the hydrophobic side of a predicted amphiphatic alpha-helix (formed by residues 14-32) in the N-terminal domain is essential for the subunit interaction.     

Challenge of BALB/c mice with respiratory syncytial virus does not enhance the Th2 pathway induced after immunization with a recombinant G fusion protein, BBG2NA, in aluminum hydroxide

The polypeptide of aa 130-230 of the G protein (G2Na) of respiratory syncytial virus (RSV) was fused to BB, the albumin-binding region of streptococcal G protein, producing BBG2Na, which induced protective immune responses in rodent models. Evaluation of the immune response in mice immunized with BBG2Na in the adjuvant alhydrogel revealed high amounts of interleukin (IL)-5 and some IL-4 in splenocytes restimulated in vitro. This is compatible with a Th2 response. The activation of the Th2 pathway in such mice was further supported by the detection of IL-5 and G2Na-specific IgE in vivo. Of interest, in contrast to immunization with formalin-inactivated RSV, immunization of mice with BBG2Na followed by intranasal RSV challenge did not lead to increased production of IL-5- or G2Na-specific IgE. However, IgG1- and IgG2a-specific antibodies were boosted. These results demonstrate that the Th2 pathway is not enhanced by RSV challenge in BBG2Na-immunized mice.     

A prospective, multicenter, randomized trial comparing steroids and pulse cyclophosphamide versus steroids and oral cyclophosphamide in the treatment of generalized Wegener's granulomatosis

OBJECTIVE: To investigate the effectiveness and side effects of oral versus pulse cyclophosphamide (CYC) in combination with corticosteroids (CS) in the treatment of systemic Wegener's granulomatosis (WG). METHODS: Patients with newly diagnosed systemic WG were enrolled in a prospective, randomized trial. At the time of diagnosis, prior to randomization, every patient received a daily injection of methylprednisolone for 3 days, followed by daily oral prednisone (1 mg/kg/day) and a 0.7-gm/m2 pulse of CYC. Patients were then randomly assigned to receive either prednisone plus intravenous pulse CYC (group A) or prednisone plus oral CYC (group B) as first-line treatment. CYC was given for at least 1 year and was then progressively tapered and discontinued. RESULTS: Fifty patients were included in the study: 27 in group A and 23 in group B. At 6 months, 24 group A patients (88.9%) were in remission, versus 18 group B patients (78.3%). At the end of the trial, 18 group A patients (66.7%) and 13 group B patients (56.5%) were in remission. In group A, 66.7% of the patients experienced side effects, versus 69.6% in group B. Infectious side effects were significantly more frequent in group B (69.6%) than in group A (40.7%) (P < 0.05). The incidence of Pneumocystis carinii pneumonia was higher in oral CYC-treated patients (30.4%) than in pulse CYC-treated patients (11.1%). Nine group A patients (33.3%) and 10 group B patients (43.5%) died. Actuarial curves showed that relapses were significantly more frequent in group A (59.2%) than in group B (13%) (P = 0.02). CONCLUSION: Our results indicate that pulse CYC is as effective as oral CYC in achieving initial remission of WG and is associated with fewer side effects and lower mortality. However, in the long term, treatment with pulse CYC does not maintain remission or prevent relapses as well as oral CYC.