Modification of ventricular tachycardia by carotid sinus massage

Imiquimod and its analogs belonging to a class of imidazoquinolinamines, activate immune system via cytokine induction, and have antitumor and antiviral effects in mammals. In this study, we showed that a related analog, designated S-28828, induced interferon (IFN) and macrophage activating cytokine(s) (macrophage activating factor, MAF) in chickens in vivo, ex vivo, and in vitro. IFN and MAF were detectable in the serum of chickens following oral administration. Serum IFN levels were the highest at 2 h after treatment. Although there was no detectable IFN in sera of chickens at 8, 24, and 48 h after treatment, high levels of interferon inducible enzyme, 2'-5' oligoadenylate synthase (2'5'OAS) were present at these time points. In vitro and ex vivo studies showed that spleen cells, bone marrow (BM) cells, and peripheral blood leukocytes (PBL) were capable of producing IFN and MAF, although spleen cells produced the highest levels. Our results suggest that S-28828 administered orally may be a useful immunoenhancing and antiviral agent for chickens.     

The supracondylar approach to the jugular tubercle and hypoglossal canal

AIMS: The primary objective of this study was to determine whether pharmacokinetic interactions occurred between interferon alpha-2b (IFN) and ribavirin in patients with chronic hepatitis C infections. Additionally this study assessed the single and multiple-dose pharmacokinetics of ribavirin and IFN, and compared the safety, tolerability and antiviral pharmacodynamics of IFN plus ribavirin compared with either drug alone. METHODS: In this open label parallel group study, patients with chronic hepatitis C were randomized to receive IFN 3 million IU thrice weekly s.c. alone, ribavirin 600 mg twice daily p.o. alone or both drugs in combination over 6 weeks. Single and multiple dose pharmacokinetics and indices of antiviral pharmacodynamics were assessed during weeks 1 and 6, along with safety assessments during the study. RESULTS: The range of mean ribavirin terminal phase half-lives after single doses was 44-49 h. Comparison of week 1 and week 6 AUC(0,12h) values showed accumulation in plasma of approximately 6-fold. The range of mean washout half-lives after week 6 was 274-298 h, reflecting release of ribavirin from deep compartment stores. The range of single and multiple dose IFN terminal phase half-lives was 5-7 h. IFN demonstrated an increase in bioavailability (approximately 2-fold) upon multiple dose administration. Ribavirin and IFN pharmacokinetic parameters for combined ribavirin and IFN were similar to those during monotherapy with either compound, although the power of this study to detect differences was low. Serum HCV-RNA titers and ALT concentrations were reduced by IFN alone, ribavirin alone reduced ALT concentrations only, and combined IFN plus ribavirin produced numerically greater falls in both measurements than either treatment alone. Serum concentrations of neopterin and activity of 2',5'-oligoadenylate synthetase (2'5'-OAS) were increased by IFN alone and in combination with ribavirin, whereas serum 2'5'-OAS activity was decreased and neopterin concentrations unaltered by ribavirin monotherapy. IFN and ribavirin monotherapy produced characteristic changes in safety laboratory tests (IFN--reductions in white cells, neutrophils and platelets; ribavirin--reduced haemoglobin) and characteristic adverse event profiles (IFN--headache, flu-like symptoms, fatigue, anorexia, nausea, myalgia, and insomnia; ribavirin--headache, fatigue, myalgia, and pruritus). There was no additive effect of combination therapy on safety laboratory tests or reported adverse events. All changes were fully reversible upon treatment cessation. CONCLUSIONS: There was no evidence of pharmacokinetic interactions between IFN and ribavirin in this study. There were numerical trends indicating that the combination of IFN and ribavirin reduced titers of HCV-RNA to a greater extent than did either treatment alone, and the safety profile of combination therapy was similar to those of both monotherapy treatments.     

Effect of retinol palmitate as a treatment for dry eye: a cytological evaluation

OBJECTIVE: To investigate a method of detecting adhesion molecule (CD44) contents in ovarian tumors and its clinical significance. METHODS: In 106 patients with ovarian tumors (50 benign and 56 malignant), the adhesion molecule (CD44) contents in peripheral blood lymphocytes (PBL) and in neoplastic tissues were analysed (quantitatively by using flow cytometric-immunological method). RESULT: (1) The CD44 contents in the PBL of the patients with malignant tumor were obviously higher than those of patients with benign tumors (P<0.05) and than those of the control (P < 0.01); (2) Within the group of patients with malignant tumors, the CD44 contents in the neoplastic tissues were higher than those in the PBL (0.01 < P < 0.05); There was no significant difference in CD44 contents among the different histopathological types, whether benign or malignant; (4) The CD44 contents in the PBL decreased gradually after surgery. CONCLUSION: To analyse the CD44 contents in PBL and neoplastic tissues by flow cytometry may be an important method or parameter to differentiate benign ovarian tumors from malignant tumors and to discover recurrence of metastasis of malignant tumors in early stage.     

The effect of interferon-alpha on the pituitary-adrenal axis

This report concerns the use of a minimum stress animal model for evaluating the neuromodulatory effects of interferon-alpha (IFN-alpha). Male Sprague-Dawley rats, 350-450 g, received jugular catheters and were habituated to handling and sampling arenas. These procedures will minimize stress usually associated with i.v. injections and blood sampling. Natural rat IFN-alpha/beta (RaIFN-alpha/beta) endotoxin free (Lee Biomolecular Research Laboratories, San Diego, CA) or recombinant human IFN-alpha, (rHuIFN-alpha) (a gift from Hoffman La Roche, Nutley, NJ) was injected into rats via catheter at various IFN concentrations. Controls were injected with either (1) vehicle (saline), (2) human or bovine serum albumin in saline, or (3) heat-denatured RaIFN-alpha/beta. Experiments were begun (0 h) at about 0900 h, and blood samples were withdrawn at intervals up to 2 h after IFN or control injections and replaced by the same volume of saline. The concentrations of corticosterone and ACTH in peripheral plasma were measured by radioimmunoassay. Both IFN, when injected at concentrations of 300 or 600 U/g body weight (U/gbw), stimulated an increase above 0 h levels of both hormones in the same animals. Additionally, the stimulation was also evident when compared with plasma hormone levels in animals injected with control substance in a parallel time course. After administration of 150 U/gbw of either IFN, only the increase in the blood corticosterone was significant. These studies demonstrate that both homospecific (RaIFN-alpha/beta) and heterospecific (rHuIFN-alpha) IFN preparations are capable of stimulating the pituitary-adrenal axis.     

Trachoma: the forgotten cause of blindness

The effects of two fungicides (carbendazim and chlorothalonil) on the induction of DNA damage in human peripheral blood lymphocytes (human PBL) have been investigated using the single cell gel electrophoresis assay (SCGE assay or comet assay) immediately after a 1-h treatment and after a 24-h post-treatment incubation. The assessment of etoposide (an effective antitumour agent) effects on human PBL in terms of cell viability and dose-DNA damage relationships was made and etoposide selected as a positive control. The results indicate that etoposide induces significant (p < 0.01) dose-dependent DNA damages for concentrations at which the loss of cell viability is low. After a 24-h recuperation period, all observed DNA damages has disappeared. With SCGE assay performed after a 1-h treatment, similar positive results were observed with chlorothalonil alone or in association with carbendazim, without any loss of cell viability. However, a dramatic loss of cell viability was measured after 24 h and was associated with a large proportion of highly damaged cells. In contrast, carbendazim was not cytotoxic on human PBL and did not induced DNA damage using the SCGE assay either immediately after treatment or after a 24-h post-treatment incubation. These results point to the necessity of an adequate evaluation of immediate and long-term cytotoxicity of compounds that are to be assessed by the SCGE assay.     

Effect of trabecular aspiration on early intraocular pressure rise after cataract surgery

The enzyme/cytokine thymidine phosphorylase/platelet-derived endothelial cell growth factor (TP/PD-ECGF) has diverse functions within cells, including the regulation of steady-state thymidine levels, the conversion of the cancer chemotherapeutic agent 5-fluorouracil (FUra) to an active metabolite, and the mediation of angiogenesis in normal and malignant cells. Although the levels of TP/PD-ECGF vary substantially among different tissues and are generally found to be elevated in tumors, little is known about the control of its expression in vivo in humans. In this study, peripheral blood mononuclear cells were obtained from patients prior to and during treatment with IFN and FUra and analyzed for TP/PD-ECGF expression. Sixteen of 21 patients (76%) exhibited an average 3-4-fold increase of TP/PD-ECGF protein levels after treatment with either IFN-alpha or-beta, with the remaining patients having either a decrease (four patients) or no change (one patient) at the sampling times examined. Expression in vivo increased rapidly within 1-2 h of IFN treatment and remained elevated for up to 48 h after its administration. The increase in TP/PD-ECGF protein was accompanied by a concomitant increase in TP/PD-ECGF mRNA levels. TP/PD-ECGF mRNA expression in cells in vitro was induced by IFN but not by pharmacologically relevant concentrations of FUra, suggesting that the IFN was responsible for the induction seen in the patients. This study demonstrates that IFN induces TP/PD-ECGF expression in vivo by regulation of the level of mRNA expression.     

Preferential cytotoxic effect of Newcastle disease virus on lymphoma cells

Susceptibility of lymphoma cells (Daudi, HD-Mar) to Newcastle disease virus toxicity was found to be higher than that of lymphoblastoid cells (Milstein) and of resting peripheral blood lymphocyte (PBL). Phytohemagglutinin- and/or pokeweed-mitogen-activated PBL however, exhibited, elevated sensitivity, similar to that of lymphoma cells. The level of cytotoxicity was monitored by cell viability, inhibition of DNA synthesis and release of 51Cr. When Daudi cells were mixed with PBL they were significantly more sensitive to the killing effect of the virus (70% mortality compared to 30% 30 h after infection, P < 0.05). The degree of sensitivity to viral cytotoxicity was unrelated to the efficacy of adsorption, which was similar for all cell lines as shown by immunofluorescent staining and flow cytometry. Also an influenza strain A/PR/8/34 (H1N1) adsorbed but did not affect the viability of any of the cells tested. Our results demonstrate that New-castle disease virus caused preferential damage to lymphoma cells as compared to non-cancerous normal cells.     

Potentiation of Fas-mediated apoptosis of murine granulosa cells by interferon-gamma, tumor necrosis factor-alpha, and cycloheximide

The Fas antigen is a transmembrane receptor belonging to the tumor necrosis factor-alpha (TNF) receptor family that, when activated by Fas ligand or agonistic antibodies, induces death by apoptosis. Although the presence of Fas antigen in ovarian tissues has been demonstrated, little is known about whether Fas antigen is functional in the ovary. This report shows that murine granulosa cells are initially resistant to antibody-induced Fas-mediated apoptosis, but will undergo apoptosis when cotreated with TNF and interferon-gamma (IFN) or cycloheximide (CX). Granulosa cells were obtained from follicles of 23-day-old mice 2 days after injection of PMSG. Twenty-four hours after plating, cells were pretreated with either 0 or 200 U/ml IFN, which has been shown to induce Fas antigen expression and is required for Fas-mediated killing in many cell types. At 48 h, cells were treated with 2 microg/ml control IgG, 2 microg/ml anti-Fas antigen antibody (Fas mAb), 10 ng/ml TNF, or Fas mAb and TNF. Cytotoxicity (percent killing) relative to control IgG was determined at 72 h by counting granulosa cells after trypsinization. In the absence of IFN, no cytotoxicity was observed. In the presence of IFN, neither TNF or Fas mAb alone was cytotoxic, but the combination of Fas mAb and TNF resulted in 25% killing (P < 0.05). Fas antigen messenger RNA (mRNA) was detectable in cultures not treated with cytokines and was increased 5-fold by TNF, 2-fold by IFN, and 17-fold by the combination of IFN and TNF. To test whether the presence of a labile inhibitor(s) of Fas-mediated killing in granulosa cells is the cause of resistance to Fas mAb, the protein synthesis inhibitor CX was used. Experiments were performed as described above, except that cells were treated with 0.5 microg/ml CX in conjunction with other treatments at 48 h. Fas mAb treatment in the presence of CX induced 25% cell death without IFN pretreatment and 38% with IFN (P < 0.05). TNF treatment in the presence of CX had no effect alone, but potentiated the effects of Fas mAb, resulting in 56% killing in the absence of IFN and 86% killing in the presence of IFN (P < 0.05). Cells stained positively for DNA fragmentation and annexin V binding, features characteristic of apoptosis. Because initial experiments showed that treatment with TNF alone increased Fas mRNA levels, the effect of pretreating cells for 24 h with TNF before treatment with Fas mAb was tested. Pretreatment with TNF or IFN alone did not promote Fas mAb-mediated killing, but combined pretreatment with TNF and IFN resulted in 25% killing in response to Fas mAb. Treatment of cells with the combination of IFN and TNF induced a 19-fold increase in Fas antigen mRNA levels. Corresponding increases in Fas antigen protein expression on the surface of cells in response to cytokine treatments were detected by immunocytochemistry. Human TNF did not duplicate the effects of mouse TNF in inducing Fas antigen mRNA expression and Fas mAb-induced killing. As human TNF interacts exclusively with the type I, but not the type II, TNF receptor in the mouse, potentiating effects of mouse TNF on the Fas pathway are probably mediated via the type II TNF receptor. The effects of cytokine treatments on levels of mRNA for FAP-1, an inhibitor of Fas-mediated apoptosis, were determined. FAP-1 mRNA was detectable in untreated granulosa cells, and levels were not altered by treatment with TNF and/or IFN. In summary, the Fas-mediated pathway of apoptosis is functional in mouse granulosa cells that are stimulated with IFN and TNF. These cytokines may function at least partially by increasing Fas antigen expression. Granulosa cells appear to have inhibitors of the Fas antigen pathway, as treatment with CX potentiates Fas-mediated death. TNF promotes Fas-mediated killing in the presence and absence of CX. Therefore, TNF is not likely to act simply by increasing Fas antigen expression or decreasing protein inhibitors of the Fas pathway, because TNF remains effec     

Cytokines and therapeutic oligonucleotides

Non-infectious UV-inactivated transmissible gastroenteritis virus (TGEV) was previously shown to induce interferon alpha (IFN alpha) secretion following in vitro incubation with blood mononuclear cells. In this study, pig foetuses at different stages of gestation were injected in utero with (a) partially UV-inactivated wild TGEV or (b) fully UV-inactivated wild or dm49-4 mutant TGEV coronavirus. Nucleated cells from foetal liver, bone marrow, spleen and blood were isolated 10 or 20 h after injection and assayed ex vivo for IFN alpha secretion by ELISPOT and ELISA techniques. The administration of TGEV induced IFN alpha-secreting cells in foetal lymphohaematopoietic organs at mid-gestation. In contrast, IFN alpha was not detected in control sham-operated foetuses. A specific point mutation in the amino acid sequence of the viral membrane glycoprotein M of TGEV mutant dm49-4 was associated with lower or absent IFN alpha in utero inducibility by mutant virus as compared with wild virus. Flow cytometry analysis did not show differences in leukocyte surface marker expression between control and TGEV- or between dm49-4 and wild virus-treated foetus cells, with the exception of a reduction in percentages of polymorphonuclear cells in TGEV-treated lymphohaematopoietic tissues, which is probably due to IFN alpha secretion. The present data provided in vivo evidence of IFN alpha secretion at the cell level in foetal lymphohaematopoietic organs. Such IFN alpha-secreting cells in lymphohaematopoietic tissues may be the source of IFN alpha detected during foetal infections.     

Induction of circulating IL-1 receptor antagonist by IFN treatment

This study was undertaken to determine whether IFN induce IL-1 receptor antagonist (IL-1Ra), a specific inhibitor of IL-1. Plasma samples were obtained from healthy volunteers (n = 5) and patients with chronic hepatitis C (n = 5) treated with IFN-alpha, and from patients with renal cell carcinoma (n = 6) treated with IFN-gamma and assayed for IL-1Ra by a specific radioimmunoassay. Both types of IFN were administered subcutaneously. In vitro studies were carried out with PBMC from healthy volunteers. A single, low and nontoxic dose (1 x 10(6) U) of IFN-alpha induced circulating IL-1Ra, which reached peak levels within 12 h. This effect was dose-dependent and more pronounced with a higher dose (5 x 10(6) U). Peak IL-1Ra levels 12 h after 5 x 10(6) U IFN-alpha were 4.16 +/- 0.35 ng/ml in healthy volunteers and 5.7 +/- 0.73 ng/ml in patients with chronic hepatitis C (difference not significant). Thereafter levels declined but remained elevated for 24 h. IFN-gamma treatment led only to a modest increase of circulating IL-1Ra even at a dose of 400 micrograms; this dose, however, was associated with side effects similar to those seen after injection of 5 x 10(6) U IFN-alpha. PBMC stimulated with IFN-alpha or IFN-gamma produced IL-1Ra in vitro. The induction of IL-1Ra may contribute to the antiviral, anti-inflammatory, and antiproliferative effects of IFN.     

Interferon-gamma potentiates interleukin (IL)-6 and tumor necrosis factor-alpha but not IL-1beta induced by endotoxin in the brain

Because interferon-gamma (IFN gamma) is present in the central nervous system during neurologic diseases associated with inflammation, its effect on endotoxin-induced cytokines was studied. Cerebrospinal fluid (CSF) and serum levels of interleukin (IL)-1beta, IL-6, and tumor necrosis factor-alpha (TNF alpha), their messenger RNA expression in brain areas (hypothalamus, hippocampus, and striatum) and in spleen were evaluated 2 and 8 h after endotoxin [lipopolysaccharide (LPS), 25 microg/rat i.c.v.], IFN gamma (2.5 microg/rat i.c.v.) or after their coadministration in rats. CSF and serum IL-1beta levels were increased by LPS alone and IFN gamma coadministration did not furtherly increase them. IFN gamma potentiated LPS effect on IL-6 and TNF alpha levels in both CSF and serum. LPS and IFN-gamma coadministration did not alter IL-1beta messenger RNA expression induced by LPS in brain areas and in spleen, but it potentiated that of IL-6 and TNF alpha. The present in vivo data show that i.c.v. coadministration of LPS and IFN gamma results in a potentiation of cytokine production (IL-6 and TNF alpha) which may trigger a cascade of events relevant to neurodegenerative processes. This action is independent of IL-1beta because the production of this cytokine is not altered by IFN gamma treatment.     

Intensive regimen of cytokines with interleukin-2 and interferon alfa-2b in selected patients with metastatic renal carcinoma

We conducted a Phase II trial using an intensive regimen combining interleukin-2 (IL2), interferon-alfa-2b (IFN), and lymphokine-activated killer (LAK) cells. The aim of this study was to evaluate the toxicity and the efficacy of this combination in selected patients with metastatic renal cell carcinoma. Thirty-one assessable patients were treated with at least one cycle of a regimen consisting of 20 x 10(6) IU/day s.c. IFN for 5 days, followed 2 days later by i.v. injections of 24 x 10(6) IU/m2/day IL2 every 8 h together with i.v. bolus of 5 x 10(6) IU/m2/day IFN every 8 h during 5 days. After a 6-day break, during which four leukophereses were performed, this i.v. combination was administered along with the LAK cell reinjections for a maximum of 5 days. Twenty-seven patients underwent the two parts of the first course of treatment; respectively, 42% and 46% of the planned dose of IL2 and IFN were administered. Several severe toxicities were observed including two treatment-related deaths. Significant tumor responses were observed in seven patients, including two complete remissions. Two of these patients remain alive without evidence of disease 36 and 40 months after treatment, respectively. This intensive regimen of IL2 together with IFN and LAK cells cannot be recommended even in selected patients with metastatic renal cell carcinoma. In addition, our results argue against the concept of a dose-response relationship in this setting.     

High levels of interferon alpha in the sera of children with dengue virus infection

We measured the levels of interferon alpha (IFN alpha) in the sera of Thai children hospitalized with dengue hemorrhagic fever (DHF) or dengue fever (DF) to examine the role of IFN alpha in dengue virus infections of humans. The percentage of patients who had detectable levels of IFN alpha (> or = 3 U/ml) was higher in patients with DHF (80%, P < 0.001) and in patients with DF (60%, P < 0.001) than in healthy Thai children (7%). The levels of IFN alpha were higher in patients with DHF and in patients with DF on the first few days after the onset of fever than in healthy Thai children. The average levels of IFN alpha in patients with DHF were high two days before defervescence, decreasing gradually until the day of defervescence. There was a subset of patients with DHF who had increasing levels of IFN alpha after defervescence. However, the levels of IFN alpha in patients with DF were not high after fever subsided. The levels of IFN alpha were not different among children with DHF grades 1, 2 and 3. Among patients with DHF, T lymphocytes were activated to a higher degree in high IFN alpha producers than in low IFN alpha producers. These results indicate that similarly high levels of IFN alpha are produced in vivo during the acute stages of DHF and DF, and that high levels of IFN alpha remain after fever subsides in some patients with DHF, but not in patients with DF.     

The effects of general anesthesia and surgery on basal and interferon stimulated natural killer cell activity of humans

Natural killer (NK) cells can lyse certain tumor cells as well as virally infected cells without prior sensitization. Animal studies have shown that general anesthesia (GA) alone or GA followed by surgery decreases both basal NK cytotoxicity and enhancement of NK activity by interferon (IFN). The purpose of this study was to determine whether similar inhibition of NK activity by anesthesia and surgery occurs in humans. Venous blood was drawn 1 h before and 20-24 h after surgery under isoflurane/N2O anesthesia. Peripheral blood mononuclear cells (PBMC) were assayed for basal and IFN-alpha-stimulated NK cytotoxicity using a chromium release assay with K562 cells as targets. Flow cytometry was used to enumerate NK, T-helper, and T-cytotoxic/suppressor cell populations in each sample. Basal NK activity was significantly depressed after GA and GA and surgery. Although the postoperative IFN treatment increased NK activity to the preoperative basal level, the level achieved was significantly lower than the level observed after IFN stimulation of PBMC as evaluated preoperatively. This decreased activity does not seem to be the result of a decrease in the percentage of circulating NK cells. The decrease in NK activity after anesthesia and surgery may lead to increased susceptibility to infection and/or tumor dissemination and thus needs to be explored. Implications: Natural killer cells can kill cancer cells and virally infected cells. This study shows that surgery with general anesthesia leads to decreased natural killer cell activity as assessed int he laboratory. This decreased natural killer cell activity may lead to infection or tumor dissemination. NK activity can be restored to presurgery levels by treating isolated NK cells with interferon-alpha.     

Implementing problem-based learning in a family medicine clerkship

BACKGROUND AND OBJECTIVES: Problem-based learning (PBL) has been implemented in the curriculum of many medical schools, but limited information is available about the outcome of this learning technique. The educational intervention presented in this paper implemented a PBL learning component in our third-year family medicine clerkship and measured the outcomes of this curricular change. METHODS: One third of the curricular time devoted to didactic teaching in our family medicine clerkship was replaced with PBL activities. Simulated cases were developed and presented to students who, with the aid of faculty facilitators, studied the cases, gathered information about the cases, and developed diagnostic and management plans for the cases. The outcome of the intervention was measured by a) comparing students' scores on the National Board of Medical Examiners (NBME) family medicine clerkship examination to scores achieved by students in the year before PBL was introduced and b) students' evaluations of the relevance and success of PBL in the clerkship curriculum. RESULTS: Students' NBME clerkship examination scores increased from a mean of 66 the year before PBL began to 73 after PBL was implemented. More than 80% of students reported that PBL was a good way to learn family medicine, and 85% reported that the PBL technique provided sufficient information to formulate learning issues. CONCLUSIONS: PBL can be introduced into a third-year family medicine clerkship curriculum with general acceptance by students. Students rated the technique highly, and their examination scores improved.     

Immunologic injury in measles virus infection. III. Presence and characterization of human cytotoxic lymphocytes

Human peripheral blood leukocytes (PBL) from patients with chronic measles virus infection (SSPE) or from immune, adult humans (convalescent from acute childhood measles virus infection) are cytotoxic for target cells infected with measles virus as measured by a 51Cr assay. Specific release of 51Cr by immune PBL occurred both with and without human antibodies added to measles virus-infected cultures. Maximal killing in the absence of added antibodies to measles virus was usually detected only after 15 to 18 hr of incubation and with a high PBL to target ratio (100:1). When antibody to measles virus was added, PBL-mediated killing of virus-infected cells was not blocked. Instead, killing was enhanced and maximal lysis occurred with fewer PBL and a shorter incubation time. This cytotoxic reaction was inhibited in a dose-response manner upon the addition of Fab fragments of IgG containing antibodies to measles virus. On the average 4 to 5 x 105 antibody molecules bound per infected target cell before initiation of antibody-enhanced PBL killing. Depletion of either glass-adhering or E-rosette-forming cells did not reduce PBL killing of measles virus-infected target cells in either system. In contrast, removal of non-E rosette or of EAC rosette-forming population of PBL almost completely abrogated cytotoxicity. When Fc-bearing cells were removed, killing of virus-infected target cells was concomitantly reduced. Lysis of measles virus-infected target cells did not require histocompatibility between the PBL and the target cell. Further, immunospecific lymphocyte killing was not enhanced by such a histocompatibility fit. These experiments indicate first, that the effector PBL involved in lysis of measles virus-infected targets are not T cells but are probably K cells and, second, that PBL obtained from patients with SSPE are competent in killing measles virus-infected targets. Moreover, sera from SSPE patients did not contain a factor(s) that blocked PBL-mediated cytotoxicity.     

Production of cytokines with antiviral activity by endothelial cells

We compared the replication of VSV in human umbilical cord vein organ cultures (OC) with that in endothelial cells detached from the vein and infected immediately or infected after 24 h in culture. In four experiments of five, the virus titers obtained in the endothelial cells infected after 24 h in culture were 10-100 times higher than in the OC and 100-1000 times higher than in the freshly detached endothelial cells. To determine whether production of IFN, TNF, and IL-6 in the various cultures correlated with the data for virus yields, we measured the amounts of these cytokines formed. The OC produced considerably larger amounts of all of these. The endothelial cells produced very little IFN and TNF. Overall, there was no clear correlation between virus production and the amounts of these cytokines formed.     

Hyperdynamic hemodynamics following high-dose interleukin 2-interferon alpha therapy in patients with metastatic renal cell carcinoma. Immunotherapy as a clinical sepsis model?

Human recombinant interleukin 2 (IL-2), alone or in combination with other cytokines, is currently under investigation for the immunotherapy of metastatic tumours. Objective responses of 20-35% have been reported in patients with disseminated melanoma and renal cell carcinoma who received high-dose intravenous IL-2 in combination with interferon-alpha (IFN alpha). However, treatment with IL-2 is complicated by a syndrome of life-threatening adverse reactions such as disseminated vascular leakage, fluid retention, severe hypotension, and (reversible) multiple organ dysfunction (MODS). A systemic inflammatory reaction (SIRS/sepsis sepsis-like haemodynamic pattern has been described in patients after IL-2 bolus application alone. Our purpose was to study the haemodynamic changes in patients treated with high-dose IL-2 administered as a constant infusion and in combination with IFN alpha. PATIENTS AND METHODS: Haemodynamic variables were obtained during therapy courses of 11 patients (aged 48 to 71 years, median 61) with metastatic renal cell carcinoma receiving immunotherapy with IL-2/IFN alpha. Therapy consisted in IFN alpha 10 x 10(10) IU/m2 body surface area (BSA) once daily on days 1-5 i.m. on a regular ward, followed by IL-2 as a constant infusion of 18 x 10(6) IU/m2 BSA on days 6-11 in an intensive care unit (ICU). Haemodynamics were first measured after 5 days of IFN alpha application and transfer to the ICU on day 6, a further 24 h after the beginning of IL-2 infusion (day 7), and the end of the therapy course (days 10 and 11). Mean arterial pressure (MAP) was measured noninvasively using an oscillometric device (Dinamap, Critikon). Mixed-venous oxygen saturation (sv O2) was measured using an CO-oxymeter (OSM 3, Radiometer) and peripheral arterial oxygen saturation (psaO2) was recorded continuously with a pulse oximeter (Oxyshuttle, Critikon). In case of haemodynamic instability, stabilisation had priority over invasive haemodynamic measurements, so that nadir values of blood pressure (BP) did not influence mean MAP and are reported separately. Lactate values and criteria for SIRS were obtained before and during IL-2 infusion. Lactate measurements were performed using an enzymatic essay (Abbot FLx). The mean effect size of the haemodynamic values, SIRS criteria, and lactate concentrations during IL-2 infusion (days 6-11) were calculated, and 95% confidence intervals for the effect sizes are indicated. RESULTS: After their daily i.m. injections of IFN alpha, patients had short episodes of fever and tachycardia without significant drops in BP. A few hours after transfer to the ICU and continuous infusion of IL-2, they developed a syndrome of fever, tachycardia and tachypnoea. The haemodynamic values after 5 days of IFN alpha therapy remained in the normal range, whereas those during IL-2 infusion strongly resembled SIRS and sepsis, with a decrease in MAP (98 to 28 mm Hg) and systemic vascular resistance (SVR, 1477 to 805 dyn.s.cm-5) and an increase in cardiac output (cardiac index 2.8 to 4.3 l.min-1.m-2). MAP often had to be stablilized with colloids during the last 48 h of therapy; 5 patients had nadir values below 60 mm Hg, or 30% below basic values in hypertensive patients. Catecholamine therapy became mandatory in 1 patient and therapy had to be discontinued. Surprisingly, some patients already had elevated plasma lactate concentrations after IFN alpha therapy. During IL-2 infusion mean plasma lactate levels increased from 2.3 to 3.2 mmol.l-1 and all patients had lactate concentrations above 2.0 mmol.l-1 at the end of therapy. During the last 48 to 72 h of IL-2 infusion, patients suffered from MODS with altered mental state (7 patients), oliogoanuria (all patients), cardiac dysrhythmias (4 patients), congestive heart failure (1 patient, which led to a second case of therapy interruption), elevated bilirubin (4 patients), and pulmonary dysfunction. In 9 patients supplementary oxygen was necessary when psaO2 fell below 92