Lymphokine profile and activation pattern of two unrelated antigen- or idiotype-specific T suppressor cell clones.

Two T suppressor (Ts) clones of different specificity have been analyzed for their lymphokine spectrum. BVI/5 is an I-Ek-restricted bovine serum albumin (BSA)-specific Ts cell clone from a CBA/J mouse tolerized by low doses of BSA. It affects directly or indirectly the function of BSA-specific T helper (Th) cells. The Ts cell clone 178-4 from a BALB/c mouse is I-Ed restricted and recognizes the public J558 Id on B cells. It prevents alpha(1----3)dextran B 1355S (Dex)-specific IgG antibody production and drives Dex-specific J558 idiotype-bearing B cells into an anergic B IgG memory cell state. Both Ts cell clones thus cause specific suppression, yet in different experimental systems using different effector mechanisms. Upon stimulation with concanavalin A or fixed CD3-specific monoclonal antibody, both clones produce high levels of interferon (IFN)-gamma and tumor necrosis factor (TNF) but in contrast to Th1 cells no interleukin (IL)-2. Both clones produce low levels of IL-3 and IL-6 but no IL-4, IL-5 and IL-9. Furthermore, unlike Th2 cells, both clones do not respond to IL-1. The mechanism of the idiotype-specific induction of anergy in Dex-specific B IgG memory cells by 178-4 Ts cells is not yet understood. BVI/5 Ts cells suppress in vitro the BSA-specific proliferation of the BSA-specific Th cell clone 83/1, as well as the response of BSA-primed CBA/LN cells. Whereas the suppressive effect on 83/1 cells is due to IFN-gamma alone the suppression of BSA-specific lymph node cells can be simulated neither by IFN-gamma nor the combination of IFN-gamma and TNF. Thus these mediators cannot account for the antigen-specific suppression by BVI/5 Ts cells in polyclonal in vitro responses from lymph node cells and probably not for the induction of in vivo unresponsiveness.     

Infliximab dependency in pediatric Crohn's disease: long-term follow-up of an unselected cohort

BACKGROUND: Infliximab is effective for induction and maintenance of remission in Crohn's disease. It is unknown how long patients should be kept on infliximab therapy. The primary aim of this study was to assess duration of effective maintenance therapy and infliximab dependency in pediatric CD patients initially responding to infliximab therapy. METHODS: All pediatric patients treated with infliximab by pediatric gastroenterologists in the Netherlands because of severe luminal or fistulizing CD with initial response to infliximab therapy were reviewed. Duration of therapy, clinical response and adverse events were recorded. RESULTS: Sixty-six CD patients (37 boys) in 10 hospitals were initially responding to infliximab therapy. Mean age at the start of infliximab therapy was 14.5 years (range, 8.1-18.5 years). Mean follow-up since infliximab was started was 41.3 months (range 12-165). In total, 991 infusions were administered. Analysis demonstrates that 15.2% of patients had prolonged response, while 56.1% were infliximab dependent and 28.8% lost response. In total, 10 patients (15.2%) developed an infection during infliximab therapy and 8 (12.1%) had an immediate allergic reaction. CONCLUSIONS: Good clinical response to maintenance infliximab therapy was seen in 70% of patients. Infliximab maintenance therapy seems very effective and safe in pediatric CD. However, more than half of the patients in this cohort is dependent on repeated infliximab infusions. The number of infliximab infusions received when patients lost response to infliximab was diverse. There was no statistical difference regarding response to infliximab therapy when started early as compared to later in the course of Crohn's disease.     

Assessing Illness Representations of Chronic Illness: Explorations of Their Disease-Specific Nature

Elaborating on the five-dimensional structure of illness representation, as described in the self-regulation model of Leventhal (1980), the present study is aimed at identifying the relevance of this generic structure for two chronic illnesses: chronic fatigue syndrome (CFS) and Addison's disease (AD). Factor analyses showed the importance of the five dimensions identity, time-line, control/cure, cause, and consequences to differ according to the type of disease. That is, the items representing the five dimensions merged together for CFS patients and AD patients in a different manner and thereby produced different factor solutions for the two patient groups. In CFS patients, a four-factor solution was identified with manageability, seriousness, personal responsibility, and external cause as the factors. In AD patients a four-factor solution was also identified but with seriousness, cause, chronicity, and controllability as the factors. The value of these findings for our understanding of the disease-specific nature of illness representation is discussed.     

Pulmonary response to silica or titanium dioxide: inflammatory cells, alveolar macrophage-derived cytokines, and histopathology

We investigated the effects of silica (SiO2) and titanium dioxide (TiO2) on the pulmonary recruitment of inflammatory cells and the ability of alveolar macrophages (AMs) to release the pro-inflammatory cytokines, interleukin 1 (IL-1) and tumor necrosis factor alpha (TNF). Rats were intratracheally instilled with 5 to 100 mg/kg of the materials, and bronchoalveolar lavage cell populations and AM cytokine release were characterized on days 1, 7, 14, and 28. Both dusts elicited dose-related increases in neutrophils, lymphocytes, and AMs; however, this response was more pronounced and persistent with SiO2. SiO2 at greater than or equal to 50 mg/kg increased AM release of IL-1 and TNF at all time points; lower SiO2 doses had either a transient or no effect on AM-derived cytokines. TiO2 did not result in AM IL-1 release and increased TNF release transiently at doses greater than or equal to 50 mg/kg. Both dusts primed AMs to release increased levels of IL-1 and TNF upon in vitro stimulation with lipopolysaccharide. Histopathology (day 28) demonstrated dose-related interstitial inflammation associated with SiO2 exposure, an effect that was less severe with TiO2. SiO2 doses of greater than or equal to 50 mg/kg elicited a granulomatous response. Development of granulomatous inflammation only at SiO2 doses for which persistent AM IL-1 release occurred suggests involvement of this cytokine in the formation of SiO2-induced granulomas. The ability of SiO2 to activate AM release of IL-1 and TNF in a more pronounced and persistent manner than TiO2 is likely responsible, at least in part, for the greater inflammation and pneumotoxicity associated with SiO2.     

Selective decontamination of the digestive tract with norfloxacin in the prevention of ICU-acquired infections: a prospective randomized study

The efficacy of relatively cheap regimen of selective decontamination (SDD) was evaluated in a diverse population of ICU patients. Patients requiring prolonged ICU stay (>5 days) were randomly allocated to a treatment group or control group. Control patients (n=52) received perioperative antimicrobial prophylaxis and antibiotic treatment was instituted only on sound clinical and bacteriological criteria. Treated patients (n=48) received gastro-intestinal and oro-pharyngeal decontamination with polymyxin E, norfloxacin, amphotericin B and systemic antibiotic prophylaxis with trimethoprim until decontamination was achieved. The rate of gram-positive infections was not altered by SDD. The incidence of gram-negative respiratory tract, urinary tract and line infections was significantly reduced from 44%, 27% and 15% respectively in the control group to 6%, 4% and 0% in the treatment group. Mortality from nosocomial sepsis and overall mortality were also significantly reduced from 15% and 54% to 0% and 31% respectively. The ICU stay was not reduced by SDD, nor was time on the ventilator or use of therapeutic antibiotics. The reduction in morbidity and mortality was achieved at a relatively low cost.     

Chequerboard titrations: the influence of the composition of serial dilutions of antibiotics on the fractional inhibitory concentration index and fractional bactericidal concentration index

Chequerboard titrations carried out with modified serial dilutions of antibiotics such that consecutive concentrations in these series were four times smaller than those in two-fold serial dilutions enable MICs and MBCs to be determined with greater accuracy. Interaction indices calculated by this method can differ markedly from those calculated on the basis of two-fold serial dilutions. The differences calculated in this study ranged from -0.30 to +1.06.     

Gating and tracking, 4D in thoracic tumours

The limited ability to control for a tumour's location compromises the accuracy with which radiation can be delivered to tumour-bearing tissue. The resultant requirement for larger treatment volumes to accommodate target uncertainty restricts the radiation dose because more surrounding normal tissue is exposed. With image-guided radiation therapy (IGRT), these volumes can be optimized and tumouricidal doses may be delivered, achieving maximum tumour control with minimal complications. Moreover, with the ability of high precision dose delivery and real-time knowledge of the target volume location, IGRT has initiated the exploration of new indications in radiotherapy such as hypofractionated radiotherapy (or stereotactic body radiotherapy), deliberate inhomogeneous dose distributions coping with tumour heterogeneity (dose painting by numbers and biologically conformal radiation therapy), and adaptive radiotherapy. In short: “individualized radiotherapy”. Tumour motion management, especially for thoracic tumours, is a particular problem in this context both for the delineation of tumours and organs at risk as well as during the actual treatment delivery. The latter will be covered in this paper with some examples based on the experience of the UZ Brussel. With the introduction of the NOVALIS system (BrainLAB, Feldkirchen, Germany) in 2000 and consecutive prototypes of the ExacTrac IGRT system, gradually a hypofractionation treatment protocol was introduced for the treatment of lung tumours and liver metastases evolving from motion-encompassing techniques towards respiratory-gated radiation therapy with audio-visual feedback and most recently dynamic tracking using the VERO system (BrainLAB, Feldkirchen, Germany). This evolution will be used to illustrate the recent developments in this particular field of research.     

Reduced incidence of severe palmar-plantar erythrodysesthesia and mucositis in a prospective multicenter phase II trial with pegylated liposomal doxorubicin at 40 mg/m2 every 4 weeks in previously treated patients with metastatic breast cancer

PURPOSE: The aim of this study was to assess whether the reduction in the total dose of pegylated liposomal doxorubicin (PLD) per cycle from 50 mg/m(2) every 4 weeks to 40 mg/m(2) every 4 weeks can effectively lower the incidence of treatment-related palmar-plantar erythrodysesthesia (PPE) and mucositis. METHODS: Patients received PLD 40 mg/m(2) every 4 weeks, and were evaluated for toxicity prior to each treatment and for response every 8 weeks. RESULTS: All patients were previously treated with at least one chemotherapy regimen for metastatic disease, and 72% of the patients had a prior exposure to an anthracycline. Forty-six evaluable patients received a median of four PLD cycles, with a median dose intensity of 10 mg/m(2)/week and a median cumulative dose of 160 mg/m(2). No National Cancer Institute Common Toxicity Criteria (NCI-CTC) grade 3 or 4 PPE was observed in these patients. NCI-CTC grade 3 or 4 mucositis occurred in 4.3% of patients, only. Response rates and survival results observed here were comparable to those observed with PLD 50 mg/m(2) every 4 weeks in a matched patient population. However, patients treated with PLD 40 mg/m(2) every 4 weeks experienced less PPE and mucositis and required clearly less dose reductions and treatment delays. CONCLUSION: The favorable safety profile observed in this study leads us to recommend the use of PLD 40 mg/m(2) every 4 weeks for patients with advanced breast cancer.