The primary and memory immune response to Epstein-Barr virus infection in vitro is characterized by a divergent production of IL-1beta/IL-6 and IL-10

Reactivation of latent Epstein-Barr virus (EBV) infection is considered to exert substantial immunomodulating activities. Little is known about EBV's modulating activities on cytokine production upon primary, in contrast to reactivated, infection. Therefore, we investigated the cytokine production of latently infected EBV-positive (EBV-pos) adults upon in vitro EBV stimulation compared to nonimmune age-matched EBV-negative (EBV-neg) donors. Production of interleukin (IL)-1beta and IL-6 was strongly decreased in peripheral blood mononuclear cell (PBMC) cultures of EBV-pos adults; in contrast, IL-10 and IL-1 receptor antagonist exhibited significantly higher levels. As expected, interferon (IFN)-gamma production was almost exclusively observed in EBV-pos donors; it was accompanied by a significantly higher IL-12 synthesis. Experiments employing T cell-depleted PBMC showed similar cytokine levels between EBV-pos and EBV-neg individuals suggesting that reactivation of EBV-specific memory T cells was responsible for the divergent cytokine profiles. Production of viral IL-10 was excluded as a reason for higher IL-10 levels in EBV-pos individuals. In conclusion, our results do not appear to relate to any primary immunological differences between EBV-neg and EBV-pos adults, but show that the EBV-specific memory response to latent EBV infection is characterized by some anti-inflammatory effects. This might be of relevance upon reactivation of latent EBV infection in vivo and provides further evidence that EBV infection acts in an immunomodulating fashion.     

Thermodilution method overestimates low cardiac output in humans

We compared 57 cardiac output measurements by the thermodilution and Fick methods in 26 patients and found that thermodilution values were higher in all 16 cases in which Fick outputs were less than 3.5 l/min. In 10 cases where Fick values were less than or equal to 2.5 l/min, thermodilution and Fick measurements differed by an average of 35%. When combined with the results of previous studies comparing the thermodilution, dye dilution, and Fick techniques, these findings suggest that the thermodilution method overestimates true cardiac output in the low output range. This overestimation probably is due to heat loss under conditions of low flow. Because the thermodilution method is used widely in patients with low output states, these findings have potentially important clinical implications.     

Endogenous opioid regulation of norepinephrine release in guinea pig hippocampus.

Release of endogenous norepinephrine was detected in guinea pig hippocampal slices using a radioligand displacement assay. Focal electrical stimulation released endogenous norepinephrine and caused a calcium-dependent reduction in specific [3H]propranolol binding at beta-adrenergic receptors in the brain slice. The mu-opioid agonist PL017 decreased norepinephrine release, and the inhibition by PL017 could be blocked by the opioid antagonist naloxone. Endogenous opioid peptides concomitantly released by tissue stimulation also decreased norepinephrine release in a naloxone-sensitive manner. These results support the hypothesis that endogenous opioids can regulate excitability in the hippocampus by presynaptic modulation of norepinephrine release.     

Assessment of HIV-1 entry inhibitors by MLV/HIV-1 pseudotyped vectors

Background  

Murine leukemia virus (MLV) vector particles can be pseudotyped with a truncated variant of the human immunodeficiency virus type 1 (HIV-1) envelope protein (Env) and selectively target gene transfer to human cells expressing both CD4 and an appropriate co-receptor. Vector transduction mimics the HIV-1 entry process and is therefore a safe tool to study HIV-1 entry.     

Envelope proteins of vesicular stomatitis virions: accessibility to iodination

The glycoprotein and, to a lesser extent, the matrix membrane protein of intact vesicular stomatitis virions were specificially iodinated by oxidation with lactoperoxidase or chloramine T. The virion envelope provided an effective barrier against iodination of nucleocapsid proteins. Selective removal of glycoprotein by trypsin or Triton X-100 exposed the membrane matrix protein to somewhat more extensive iodination but the nucleocapsid N protein became only slightly more accessible to iodination; the nucleocapsid L and NS proteins remained unlabeled.     

Pro-megakaryoblasts in bone marrow tissue from patients with primary (idiopathic) osteo-myelofibrosis (agnogenic myeloid metaplasia). An immunomorphometric study on trephine biopsies

An immunomorphometric study was performed on bone marrow biopsies from 40 patients with primary osteomyelofibrosis--OMF, (agnogenic myeloid metaplasia) by employment of a monoclonal antibody against glycoprotein IIIa (Y2/51) to determine the number of pro-megakaryoblasts. Specimens from 15 individuals without any hematological disorder served as controls. With reference to the pertinent literature on megakaryocyte precursors and following a pilot study on corresponding smears, in tissue sections pro-megakaryoblasts were characterized by a size of 42.1 +/- 2.6 microns 2 (diameter 7.5 +/- 0.3 microns). In comparison with controls, in OMF no relevant increase in the number of pro-megakaryoblasts per square and cubic millimeter bone marrow was evaluable. The relative frequency of these precursors was significantly reduced due to an increase in the total amount of conspicuously large and abnormal megakaryocytes. Statistical analysis failed to reveal any correlations between counts for pro-megakaryoblasts or the total number of Y2/51--positive megakaryocytic elements with the density of argyrophilic fibers (determined by morphometry) or the platelet values. Our findings imply that in OMF the marked increase in circulating progenitor cells of the megakaryocyte lineage may be generated by extramedullary, probably splenic hematopoiesis. Moreover, the evolution of medullary fibrosis is thought to be associated with the striking predominance of large atypical, possibly overaged and hyperpolyploid megakaryocytes and not with an increase in precursor cells.     

Treatment of AIDS-related cutaneous Kaposi's sarcoma with topical alitretinoin (9-cis-retinoic acid) gel. Panretin Gel North American Study Group

BACKGROUND: Kaposi's sarcoma (KS) is the most frequent malignancy in patients with HIV. Given the promise that retinoids show in the treatment of various hyperproliferative skin disorders and in vitro evidence of inhibition of proliferation of KS cells, a randomized, controlled clinical trial was conducted. METHODS AND RESULTS: A 12-week, multicenter, randomized, double-blind, vehicle-controlled safety and efficacy evaluation of topical alitretinoin 0.1% gel applied to cutaneous KS lesions was conducted in HIV-infected patients. The primary efficacy endpoint was the patient's response rate, as determined by evaluating six index lesions representative of the patient's overall KS cutaneous disease using AIDS Clinical Trials Group (ACTG) response criteria applied to topical therapy. Of 268 patients entered in the blinded treatment phase of the study (alitretinoin group, n = 134; vehicle group, n = 134), 47 patients (35%) treated with alitretinoin 0.1% gel had a positive response, compared with 24 patients (18%) treated with vehicle gel. Of 184 patients receiving open-label alitretinoin treatment following the blinded phase of the trial, 90 patients (49%) met criteria for a positive response. This superior efficacy of alitretinoin gel over vehicle gel was maintained when the data were adjusted or analyzed for age, race, Kamofsky scores, baseline CD4+ lymphocyte counts, number of raised lesions at baseline, and aggregate area of index lesions. Alitretinoin 0.1% gel was superior to vehicle gel regardless of the number of concurrent antiretroviral therapies. Most adverse events were mild to moderate in severity, limited to the application site, and reversible on reduction in frequency or suspension of application. Relatively few patients (7%) discontinued alitretinoin therapy because of to related adverse events. CONCLUSIONS: The results show that alitretinoin gel application is safe and generally well tolerated, and they indicate the superiority of alitretinoin 0.1% gel over vehicle gel in the treatment of cutaneous AIDS-related KS lesions.     

Geometrically based optimization for extracranial radiosurgery

For static beam conformal intracranial radiosurgery, geometry of the beam arrangement dominates overall dose distribution. Maximizing beam separation in three dimensions decreases beam overlap, thus maximizing dose conformality and gradient outside of the target volume. Webb proposed arrangements of isotropically convergent beams that could be used as the starting point for a radiotherapy optimization process. We have developed an extracranial radiosurgery optimization method by extending Webb's isotropic beam arrangements to deliverable beam arrangements. This method uses an arrangement of N maximally separated converging vectors within the space available for beam delivery. Each bouquet of isotropic beam vectors is generated by a random sampling process that iteratively maximizes beam separation. Next, beam arrangement is optimized for critical structure avoidance while maintaining minimal overlap between beam entrance and exit pathways. This geometrically optimized beam set can then be used as a template for either conformal beam or intensity modulated extracranial radiosurgery. Preliminary results suggest that using this technique with conformal beam planning provides high plan conformality, a steep dose gradient outside of the tumour volume and acceptable critical structure avoidance in the majority of clinical cases.