Extrapolating empirical long-term survival data: the impact of updated follow-up data and parametric extrapolation methods on survival estimates in multiple myeloma.

BACKGROUND: In economic evaluations, survival is often extrapolated to smooth out the Kaplan-Meier estimate and because the available data (e.g., from randomized controlled trials) are often right censored. Validation of the accuracy of extrapolated results can depend on the length of follow-up and the assumptions made about the survival hazard. Here, we analyze the accuracy of different extrapolation techniques while varying the data cut-off to estimate long-term survival in newly diagnosed multiple myeloma (MM) patients. METHODS: Empirical data were available from a randomized controlled trial and a registry for MM patients treated with melphalan + prednisone, thalidomide, and bortezomib- based regimens. Standard parametric and spline models were fitted while artificially reducing follow-up by introducing database locks. The maximum follow-up for these locks varied from 3 to 13 years. Extrapolated (conditional) restricted mean survival time (RMST) was compared to the Kaplan-Meier RMST and models were selected according to statistical tests, and visual fit. RESULTS: For all treatments, the RMST error decreased when follow-up and the absolute number of events increased, and censoring decreased. The decline in RMST error was highest when maximum follow-up exceeded six years. However, even when censoring is low there can still be considerable deviations in the extrapolated RMST conditional on survival until extrapolation when compared to the KM-estimate. CONCLUSIONS: We demonstrate that both standard parametric and spline models could be worthy candidates when extrapolating survival for the populations examined. Nevertheless, researchers and decision makers should be wary of uncertainty in results even when censoring has decreased, and the number of events has increased.

Correction to: Implementing a hospital-wide protocol for Staphylococcus aureus bacteremia.

The article "Implementing a hospital-wide protocol for Staphylococcus aureus bacteremia", written by K. Bolhuis, L. J. Bakker, J. T. Keijer, and P. J. de Vries was originally published electronically on 31 May 2018 with incorrect copyright line in the publisher's internet portal.

Implementing a hospital-wide protocol for Staphylococcus aureus bacteremia.

Staphylococcus aureus bacteraemia (SAB) is associated with high-mortality and complication rates. A multidisciplinary approach is needed to predict, detect and treat complications. In this pre- and post-intervention study, we investigated the effects of a hospital-wide protocol for diagnosis, classification and treatment of SAB. It was hypothesized that complications and endocarditis would be better identified and treated. Medical records of SAB patients admitted in 2011 and 2012 (pre) were analysed. In 2013, a protocol, describing risk factors, diagnostic classification and recommended treatment, was implemented. In 2014 and 2015 (post), SAB patients were followed prospectively. Transthoracic (TTE) or transoesophageal cardiac ultrasound (TEE) was chosen following a decision tree. A resident internal medicine acted as contact person. Pre-intervention, 98 patients were eligible for analysis compared to 85 patients post-intervention. Age and number of risk factors were slightly higher post-intervention; other baseline characteristics were similar. Most SAB-patients were classified as complicated (89 and 82% pre- and post-intervention, respectively). Follow-up blood cultures drawn within 2 days after initiating treatment increased from 51 to 85%. Cardiac ultrasounds increased from 44 to 83% for TTE and 13 to 24% for TEE. Endocarditis was more frequently diagnosed (4 vs. 12%). Additionally, duration of antibiotic therapy increased. The 3-month mortality did not change significantly (33% pre-intervention vs. 35% post-intervention; p > 0.05). Introduction of a hospital-wide protocol for SAB management increased standard of care, created awareness among clinicians to properly classify SAB, search for endocarditis and adapt duration of antibiotic treatment. Mortality did not decrease.

Impact of transition from microscopy to molecular screening for detection of intestinal protozoa in Dutch patients.

Detection of intestinal protozoa by PCR methods has been described as being sensitive and specific, and as improving the diagnostic yield. Here we present the outcome of the transition from microscopy to molecular screening for detection of a select group of intestinal protozoa in faeces in our laboratory. Introduction of molecular screening for intestinal protozoa resulted in higher sensitivity, reduced hands-on-time, reduced time-to-results, leading to improved diagnostic efficiency.

[Ocular infection by Pseudomonas aeruginosa in a mechanically ventilated patient]. / Ooginfectie door Pseudomonas aeruginosa bij een mechanisch beademde patiënt.

A 59-year-old man developed bilateral keratitis several weeks after the initiation of mechanical ventilation because of respiratory failure and sepsis following abdominal surgery. Colonisation of the upper airways by P. aeruginosa had been established before. Invasion through corneal epithelial defects based on dehydration keratitis was the presumed route of infection. Despite aggressive treatment, including antibiotics, the infection was rapidly progressive in both eyes. The patient died of deterioration of his general condition. In order to prevent such eye infections in a patient on mechanical ventilation, there is a need of good eye care, prevention of corneal lesions and alertness, especially when the patient is colonised by virulent micro-organisms like P. aeruginosa.

Phagocytic function of monocyte-derived macrophages is not affected by human immunodeficiency virus type 1 infection.

The immunopathogenesis of human immunodeficiency virus (HIV) infection is characterized by the failure to control opportunistic infections. Here, the direct effect of HIV on macrophage phagocytic function was studied. HIV-1-infected monocyte-derived macrophages expressed as many Fc gamma and complement receptors as did control macrophages. The function of these receptors was not affected by HIV-1 infection since binding and internalization of opsonized Escherichia coli and Staphylococcus aureus were not impaired. Production of reactive oxygen species induced by stimulation of the HIV-1-infected macrophages with opsonized E. coli, zymosan, or PMA was intact. HIV-1-infected macrophages killed opsonized E. coli and Candida albicans as effectively as did control macrophages. These results, therefore, do not support the hypothesis that HIV-1 infection of macrophages causes phagocytic dysfunction and suggest that HIV-induced abnormalities outside the mononuclear phagocyte system may lead to the inability to control opportunistic pathogens.

Infection of epithelial cell line HEp-2 with human immunodeficiency virus type 1 is CD4 dependent.

HEp-2 cells, human epithelial cells derived from a larynx carcinoma, were found to be highly susceptible to infection with HIV-1 stain IIIb and MN, but not to infection with the monotropic strain IIIBa-L or the clinical isolate HIV-1AT. HEp-2 cells infected with HIV-1 IIIb continuously secreted high levels of p24 antigen, while no cytopathic effects were observed. Although no CD4 antigen could be detected on the cells by flow cytometric analysis, CD4 mRNA was detected by reverse transcriptase PCR. Furthermore, infection could be blocked by anti-CD4 monoclonal antibody OKT4a indicating a CD4 mediated viral entry in HEp-2 cells. HEp-2 cells are commonly used in clinical virology for the culture of different viruses from clinical specimens. HEp-2 cells should therefore be handled with caution as they may potentially become infected with HIV.

Down-regulation of human immunodeficiency virus type (HIV-1) production after stimulation of monocyte-derived macrophages infected with HIV-1.

Macrophages infected with human immunodeficiency virus (HIV) can be stimulated as a result of secondary infections. The effect of stimulation of HIV-1-infected monocyte-derived macrophages on HIV-1 production by these cells was studied. Exposure of macrophages to phorbol 12-myristate 13-acetate or to opsonized Escherichia coli, Staphylococcus aureus, or zymosan resulted in a decrease in HIV production. HIV production was inversely related to the degree of stimulation, measured as lucigenin-enhanced chemoluminescence. The production of reactive oxygen intermediates, however, did not seem to be the direct cause of the diminished HIV production, since oxygen-radical scavengers did not prevent the decrease in HIV production. Furthermore, oxygen-radical scavengers did not affect HIV production by nonstimulated macrophages. These results indicate that activation signals have an opposite effect and reactive oxygen intermediates have no effect on HIV production in macrophages compared with the effect described in T cells.

Binding of human immunodeficiency virus type-1 to follicular dendritic cells in vitro is complement dependent.

The authors studied the binding in vitro of HIV-1 virus particles, conjugated to fluorescein isothiocyanate, to follicular dendritic cells (FDC) isolated from human tonsils. Analysis was done using flow cytometry, fluorescence microscopy, and immunogold electron microscopy. The focus of study was on the effect of serum from various origins, including pooled fresh serum and heated serum from control donors and pooled heated serum from HIV-1-infected patients (containing anti-HIV-1 antibodies). In the presence of heated serum, either from controls or from HIV-1-infected patients, the fluorescence signal in flow cytometry was similar to the background value. In the presence of fresh serum, the signal was substantially increased, and an even higher signal was observed in the presence of fresh serum and serum from HIV-1-infected patients. This high fluorescence signal was also found in the presence of serum depleted of complement factor C5, but not with serum deficient in complement factor C3. The binding of HIV-1 virions to FDC in the presence of fresh serum was confirmed by fluorescence microscopy on cytospot preparations. After quenching of the extracellular fluorescence with trypan blue, the fluorescence was reduced to about 30% of the initial value, indicating that most of bound fluorescent virions were present extracellularly. Similar experiments using blood mononuclear cells showed that fluorescent HIV-1 particles after binding to these cells were present intracellularly. This flow cytometry data was confirmed in immunogold electron microscopy demonstrating that most HIV-1 gag p24 or FITC label was present at the outside of FDC and on adherent virus particles. We conclude that HIV-1 virions adhere to FDC in vitro in a complement component C3-dependent way. Anti-HIV-1 antibodies in serum from HIV-1 infected patients enhance binding but, by itself, are unable to mediate binding.

Antibody mediated enhancement of HIV-1 infection of an EBV transformed B cell line is CD4 dependent.

Low levels of anti-viral antibodies may facilitate virus infection of Fc-receptor bearing cells. For human immunodeficiency virus (HIV) it has been reported that antibodies can enhance infection of phagocytic cells. We show that HIV-1 can infect an Epstein-Barr virus transformed B cell line and that low levels of anti-HIV antibodies enhance infection. The enhanced infection was characterized by an increase in viral DNA and increased HIV p24 protein production. Detection of cell surface antigen expression of CD4, the receptor for HIV, Fc-receptor type II for IgG, but not of type I and III could be demonstrated by immunofluorescence cytometry. The enhancement was abrogated when infection was performed in presence of a monoclonal antibody directed against CD4. Based on these results we conclude that antibody mediated enhancement of HIV-1 infection can also occur in non-phagocytic cells in a CD4 dependent manner and that IgG Fc-receptors other than types I or III are involved in this process.

Antibodies and complement enhance binding and uptake of HIV-1 by human monocytes.

OBJECTIVE: To characterize antibody- and complement-mediated binding and uptake of HIV-1 by human monocytes. DESIGN: The first step in the infection of the monocyte by HIV-1 is binding of the virus to the susceptible cell. Procedures were designed to assess the influence of anti-HIV-1 antibodies and complement on this binding, and to study the process of internalization following binding. METHODS: Human monocytes were incubated with fluorescein-labelled purified HTLV-IIIB virions and human sera with high-titre anti-HIV-1 antibodies and/or complement. Binding and uptake of virus by the monocytes was measured as fluorescence per cell by flow cytometry. RESULTS: Binding of purified HIV-1 to monocytes was increased by complement and, to a lesser extent, by anti-HIV-1 antibodies. Uptake of HIV-1 bound to the monocyte appeared to be mediated by antibodies and was increased further by the presence of complement. Complement alone, however, resulted in the uptake of only a small part of the bound virus. CONCLUSIONS: Complement significantly increases the binding of HIV-1 to human monocytes, and a combination of antibodies and complement efficiently mediates uptake of HIV-1 by monocytes.

Nocardia asteroides pneumonia complicating low dose methotrexate treatment of refractory rheumatoid arthritis.

Low dose methotrexate is used increasingly often in the treatment of rheumatoid arthritis. Severe complications due to toxicity of the lung or bone marrow occur infrequently. This report describes a 71 year old woman with longstanding rheumatoid arthritis who developed pleuritis, a pulmonary infiltrate, and pancytopenia during treatment with low dose methotrexate. Fatal respiratory insufficiency followed, and cultures from the lung after death showed Nocardia asteroides.

Antipyrine, indocyanine green, and lorazepam determined in plasma by high-pressure liquid chromatography.

This HPLC method for measuring antipyrine, lorazepam, and indocyanine green in 0.5 mL of plasma can be used in studies of liver function in which these "model" compounds are used. After a fast, simple, one-step extraction procedure with acetonitrile, an isocratic HPLC system is used, with a single detection wavelength (214 nm) and a single internal standard (1-acetamidopyrene). The mobile phase is a 47/53 (by vol) mixture of acetonitrile and 50 mmol/L phosphate buffer, pH 6. The three compounds are separated on an LC-18 reversed-phase column. The low cost of the HPLC method makes feasible the routine clinical measurement of all three compounds.

Carumonam (Ro 17-2301; AMA-1080) compared with gentamicin for treatment of complicated urinary tract infections.

Carumonam and gentamicin were compared in a prospective, randomized study of 52 patients with complicated urinary tract infections. Patients were treated with either carumonam (1 g every 8 h) or gentamicin (1 mg/kg every 8 h). The mean duration of therapy (carumonam, 8.5 days; gentamicin, 8.5 days) was similar for both groups. A total of 45% of patients treated with carumonam and 48% of those receiving gentamicin were cured, as defined by a negative culture 1 to 2 weeks after therapy. After 4 to 6 weeks, the figures were 27% for carumonam and 38% for gentamicin. In the carumonam group, there were 6 relapses and 11 reinfections. In the gentamicin group, there were eight relapses and five reinfections. Adverse effects in the carumonam group were limited to phlebitis at the intravenous infusion site in two patients; another patient developed bloody diarrhea. Nephrotoxicity was documented in two patients in the gentamicin treatment group (9%), and another patient developed minor liver function disturbances. Three patients with gentamicin-resistant carumonam-susceptible isolates were treated with carumonam, and two were cured. Urinary colonization with group D streptococci occurred in 7 of 27 (26%) carumonam-treated patients compared with 7 of 19 (37%) gentamicin-treated patients; no one required treatment. A significant correlation was found between colonization with group D streptococci and neurogenic bladder dysfunction (P less than 0.007). It is concluded that the use of the carumonam is as effective as the gentamicin regimen in the treatment of complicated urinary tract infections.