Epitope Context and Reshaping of Activated T Helper Cell Repertoire

In recent years, a growing interest in the study of peptide antigenicity in relation to the role of flanking sequences and protein topology in processing, presentation, and recognition has been observed. However, the information available on the antigenicity of recombinant fusion proteins and their effect on the selection of antigen receptor repertoires is limited. To analyze the role of molecular topology of T epitopes in a system relevant to human pathology, we have used the bacterially expressed Schistosoma japonicum glutathione S transferase (GST) to construct recombinant antigens containing HIV-1 derived T cell determinants, and human T cell clones specific for these determinants. We found that antigenicity of a given GST—peptide combination was not the same when T cells and antigen presenting cells from different individuals were tested. Our results show that differences in processing and presentation of chimeric proteins are not dictated by the use of diverse restriction elements. We also found that the context in which an antigenic peptide is delivered affects the recruited repertoire as defined according to T cell receptor Vβ usage and fine specificities of selected T cells.     

Lowβ-glucuronidase activity in a healthy member of a family with mucopolysaccharidosis VII

Summary A phenotypically normal mother of a mucopolysaccharidosis VII child, is reported with an unusually low-glucuronidase activity. Low enzyme activity was systemic (6–10% of controls) and residual-glucuronidase in leukocytes had an apparently normalK _m value. [³⁵S]sulphate incorporation and chase assays in fibroblasts gave values similar to control cells. A normal excretion pattern of glycosaminoglycan was found in this woman's urine. Low enzymatic activity can be related to a non-pathological pseudodeficiency allele for-glucuronidase; this woman appears to be an apparent compound heterozygote for this allele and mucopolysaccharidosis VII. Her next pregnancy was monitored by chorionic villus sampling and a heterozygous fetus was suspected. These studies stress the need for complete enzyme investigations of obligate carriers for mucopolysaccharidoses in order to prevent difficulties at prenatal analysis.     

Phase II trial of fortnightly irinotecan (CPT-11) in the treatment of colorectal cancer patients resistant to previous fluoropyrimidine-based chemotherapy

Introduction This phase II study investigated the anti-tumour activity and toxicity of CPT-11 (250 mg/m2 i.v. infusion over 60 minutes) administered every 2 weeks as second-line chemotherapy in patients with advanced colorectal cancer (CRC). Material and methods Patients (n=63) with histology diagnosis of advanced CRC and proven resistance to previous fluoropyrimidine therapy were enrolled. Results A total of 510 CPT-11 cycles were administered, with a mean of 8 cycles per patient (range: 1–32). The median relative dose intensity was 93%. Partial response (PR) was obtained in 11 patients (17.5%; 95%CI: 8.1%–26.7%) and 29 patients (46.0%) showed stable disease (clinical benefit of 63.5%). The median duration of response was 6.8 months (95%CI: 6.1–7.5 months), median survival was 8.8 months (95%CI: 6.3–11.5 months) and median time to disease progression was 4.5 months (95%CI: 3.9–5.0 months). Overall, this schedule of CPT-11 chemotherapy was well tolerated by the patient. Neutropenia was the most frequent grade 3/4 haematological toxicity (20.6% of patients and 4.1% of cycles). Neutropenia with concurrent fever or infection occurred in 7 patients (11.1%). Late onset diarrhoea was the most frequent grade 3/4 non-haematological toxicity (19.0% of patients and 2.3% of cycles). Other, lower-incidence, toxicities were anaemia, fever, infection, mucositis, nausea and vomiting. There were no toxic deaths. Conclusions We found that CPT-11, administered as 250 mg/m² i.v. infusion over 60 minutes every 2 weeks, was active and well tolerated schedule in the second-line chemotherapy of advanced CRC patients. This bi-weekly scheme could be used as an alternative to the weekly or the every-three-week schedule as well as in combined therapies with other chemotherapeutic agents for the treatment of advanced, metastatic, CRC.     

Spatial fractionation of the dose in proton therapy: Proton minibeam radiation therapy

In radiation therapy, a renewed interest is emerging for the study of spatially fractionated irradiation. In this article, a few applications using spatial fractionation of the dose will be discussed with a focus on proton minibeam radiation therapy. Examples of calculated dose (1D profiles and 2D dose distributions) and biological evidence obtained so far will be presented for various spatially fractionated techniques GRID, micro- and minibeam radiation therapy. Recent results demonstrating that proton minibeam radiation therapy leads to an increase in normal tissues sparing will be discussed, which opens the door to a dose escalation in the tumour and a possibly efficient treatment of very radioresistant tumours.     

Pulsed electromagnetic fields decrease proinflammatory cytokine secretion (IL-1�� and TNF-��) on human fibroblast-like cell culture

The clinical use of pulsed electromagnetic fields (PEMF) in osteoarticular pathology is widely extended, although the mechanisms involved are unknown. The aim of this study was to evaluate the action of a new protocol of treatment with PEMF on liquid medium cultures of fibroblast-like cells derivates of mononuclear peripheral blood cells. Fibroblast-like cells growth was obtained in liquid medium culture from mononuclear cells (MNC) of human peripheral blood. The PEMF irradiation protocol included an intensity of 2.25 mT, a frequency of 50 Hz and an application time of 15 min on days 7, 8 and 9 of cell culture. Immunophenotype was performed with specific heterologous monoclonal antibodies for each cell receptor (Vimentin, Cytokeratin, CD34, CD41, CD61 and CD68). The cytokines’ production was determined in the supernatant of the culture medium by means of the Luminex technology. The immunophenotype did not show any statistical difference on comparing treated against non-treated cell cultures on any of the days. In the treatment cell population, the proinflammatory cytokines, IL-1β and TNF-α showed a significant decrease on days 14 and 21 of the culture, whilst IL-10 increased significantly on day 21. It is concluded that PEMF irradiation does not alter the cell immunophenotype of the fibroblast-like cell population, but does provoke a decrease in the production of inflammatory-type cytokines (IL-1β, TNF-α) and an increase in cytokines of lymphocytic origin (IL-10). These facts coincide with the chronology of the clinical effect undergone by patients with osteoarticular pathology after PEMF irradiation.     

Pulmonary Aspergillosis: Spectrum of Disease

Aspergillus species are ubiquitous in the environment. Aspergillosis is acquired by inhalation of Aspergillus spores. In normal hosts, spore inhalation rarely causes lung disease. Pulmonary Aspergillosis covers a wide spectrum of clinical syndromes depending on the interaction between Aspergillus and the host (immune-status, prior bronchopulmonary disease). It runs the gamut from invasive Aspergillosis to Aspergillus bronchitis. Invasive Aspergillosis usually occurs in severely immunocompromised patients, typically in neutropenic but also in non-neutropenic patients. Chronic pulmonary Aspergillosis affects patients with chronic structural lung disease such as COPD or previous mycobacterial lung disease, but without other significant immunocompromise. Aspergillus bronchitis affects patients with bronchial disease such as bronchiectasis. Allergic bronchopulmonary Aspergillosis affects patients with bronchial asthma or cystic fibrosis, and is due to an allergic response to Aspergillus.     

Oxidized to non-oxidized lipoprotein ratios are associated with arteriosclerosis and the metabolic syndrome in diabetic patients

Background and aimType 2 diabetic patients have a greater prevalence of the metabolic syndrome, oxidative stress and accelerated atherosclerosis, compared to non-diabetics. We examined the association between biomarkers of lipid peroxidation and the presence of atherosclerosis and the metabolic syndrome in diabetic patients.Methods and resultsWe studied oxidized LDL (OxLDL), OxLDL/LDL, OxLDL/HDL, lipoperoxides, autoantibodies against OxLDL (OxLDL-Ab), diene formation of LDL (lag phase), vitamin E, vitamin E/cholesterol and PON1 polymorphisms (−108C > T, 55T > A, and 192A > G) in 166 non-smoking type 2 diabetic patients, 119 fulfilling the criteria for the metabolic syndrome, 73 with atherosclerosis and 93 without atherosclerosis. Patients with macrovascular disease had higher values of OxLDL/LDL (11%; P = 0.016), OxLDL/HDL (18%; P = 0.024) and OxLDL-Ab (12%; P = 0.046). OxLDL/LDL and OxLDL/HDL were correlated with the number of components of the metabolic syndrome (P < 0.001). PON1 polymorphisms were not associated to LDL oxidation markers, only PON1 (−108TT) was weakly associated with higher OxLDL-Ab concentrations (22%; P = 0.040) in patients with atherosclerosis.ConclusionOxLDL/LDL, OxLDL/HDL and OxLDL-Ab are the most useful clinical parameters of lipoprotein oxidation for discriminating the presence of macrovascular disease in diabetic patients. The presence of the metabolic syndrome in these patients is also associated with an increase in the oxidized lipoprotein ratios.     

Influence of the vitamin D receptor gene polymorphism on bone loss in men after liver transplantation

BACKGROUND: Bone loss is a frequent complication after liver transplantation. OBJECTIVE: To investigate whether vitamin D receptor gene polymorphism influences bone loss in men after liver transplantation. DESIGN: Prospective cohort study. SETTING: University hospital. PATIENTS: 55 male candidates for liver transplantation. MEASUREMENTS: Lumbar spine bone mineral density was measured before and 3, 6, 12, and 24 months after liver transplantation. Vitamin D receptor genotype was determined by restriction endonuclease Bsml. RESULTS: Vitamin D receptor genotypes were significantly associated with post-transplantation changes in bone mineral density (P = 0.028). Within 3 months after transplantation, patients with the genotypes Bb or BB showed a vertebral bone loss substantially greater than that in patients with the bb genotype (between-group difference in the percentage change with respect to baseline bone mineral density, 3.7% [95% CI, 0.6% to 6.9%1). In 3 to 24 months after transplantation, bone mineral density increased steadily in the three allelic groups. CONCLUSIONS: Vitamin D receptor gene polymorphism influences bone loss after liver transplantation. Patients with the bb genotype are, to some extent, protected against post-transplantation bone loss.