Photo quiz. Melaena in a liver transplant recipient.
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Adult↗
Biomedical subjects
A P van den Berg
Publications and source records attributed to A P van den Berg.
Increased incidence of azathioprine-induced pancreatitis in Crohn's disease compared with other diseases.
BACKGROUND: Azathioprine is widely used in Crohn's disease. A major drawback is the occurrence of side-effects, especially acute pancreatitis. Acute pancreatitis is rarely seen when azathioprine is used for other diseases than Crohn's disease. AIM: To survey side-effects of azathioprine after liver or renal transplantation, for systemic lupus erythematosis, Wegener's granulomatosis, autoimmune hepatitis, rheumatoid arthritis, ulcerative colitis or Crohn's disease. METHODS: A computerized search using the term 'azathioprine' or 'imuran' was performed on the Hospital Information System of the university hospital Groningen, resulting in 1564 patients matching our criteria. RESULTS: Eleven of 224 patients with Crohn's disease experienced acute pancreatitis (4.9%) compared with two of 129 (1.5%) with autoimmune hepatitis, two of 388 (0.5%) after renal transplantation, one of 254 (0.4%) after liver transplantation. Acute pancreatitis was more prevalent in Crohn's disease compared with any other disease. Azathioprine-toxicity necessitating withdrawal occurred significantly (P < 0,05) more in rheumatoid arthritis (78 of 317), ulcerative colitis (20 of 94) and Crohn's disease (52 of 224) compared with systemic lupus erythematosis (five of 73), Wegener's granulomatosis (six of 85), autoimmune hepatitis (eight of 129), after liver transplantation (17 of 254) and after renal transplantation (22 of 388). CONCLUSIONS: Acute pancreatitis is strongly associated with Crohn's disease and rarely occurs with other underlying conditions. Overall azathioprine-induced toxicity and the necessity of withdrawal is more common in inflammatory bowel disease and rheumatoid arthritis compared with other diseases.
Acute Disease↗
Autoimmune hepatitis: clinical and immunological features.
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Hepatitis, Autoimmune↗
Hepatitis C virus infection.
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Antiviral Agents↗
A moderate elevation of blood glucose level increases the effectiveness of thermoradiotherapy in a rat tumor model. I. Relative contributions of glucose and heating to tumor acidification.
PURPOSE: To establish dose-effect relationships for tumor acidification induced by heat and glucose as a basis for testing the value of adding glucose administration to combined heat and x-ray treatment at clinically achievable glucose and temperature levels. METHODS AND MATERIALS: Rhabdomyosarcoma BA1112 was grown s.c. in the upper leg of 16-20-week-old Wag/Rij rats. Animals were given 2 consecutive 100-min periods of saline (S) or glucose (G) infusion, while keeping tumor temperature at 37 degrees, 42 degrees, or 43 degrees C for 1 or 2 periods, in various combinations, each involving 6 animals. Glucose was infused i.v. as a 20% solution at 2.4-3 g/kg/h. Tumors were heated using 2,450-MHz electromagnetic radiation, and tumor pH was measured using a 0.7 mm fiberoptic probe. RESULTS: Mean overall baseline pH was 7.00 (SD 0.10). The change induced by G37G43 (i.e., glucose infusion for a full 200 min, first 100 min at 37 degrees C, final 100 min at 43 degrees C) was -0.48 +/- 0.03 (SEM) pH units, and -0.17 +/- 0.03 for S37S43. The effect of G37G42 was -0.37 +/- 0.03 pH units, compared with -0.08 +/- 0.02 for S37S42 and -0.28 +/- 0.04 for glucose alone (G37G37). Glucose was less effective when given after or fully parallel to heating: -0.21 +/- 0.02 pH units for S43G37 and -0.37 +/- 0.02 for G43G43. CONCLUSION: The glucose-induced tumor pH drop is much more pronounced than that induced by heat, both of which are dose dependent. The effects of glucose and heat seem additive if heating is started when glucose-induced acidification has reached its plateau level, but the overall effect is diminished if administration is fully simultaneous or in reversed order. Schedule G37G43 is optimal with respect to tumor acidification. Its predicted superiority in thermoradiotherapy as compared with S37S42, S37S43, and G37G42 treatment regimens was confirmed in a subsequent experimental tumor control study.
Animals↗
A moderate elevation of blood glucose level increases the effectiveness of thermoradiotherapy in a rat tumor model II. Improved tumor control at clinically achievable temperatures.
PURPOSE: To assess the therapeutic gain (at the TCD(50) level) that can be obtained by boosting thermoradiotherapy with intravenous glucose infusion at different temperatures. This completes our series of studies to determine the optimal conditions and the effectiveness of glucose administration at clinically achievable glucose levels and treatment temperatures. METHODS AND MATERIALS: Subcutaneous rat rhabdomyosarcoma BA1112 was irradiated with graded single doses of 300-kV X-rays (dose range 0-60 Gy). Fifteen minutes after irradiation, a 100-min intravenous infusion was started, consisting of either glucose (20% solution, 2.4-3 g/kg/h) or saline as a control. Then heat was applied to the tumors at 42 degrees C or 43 degrees C (water bath) during a subsequent 100-min period of infusion. Tumor control was scored as the absence of palpable growth at 100 days after treatment. RESULTS: Glucose infusion enhanced tumor control independent of temperature in the range 42-43 degrees C. At 42 degrees C, the TCD(50) for X-irradiation decreased by 5.9 Gy (SEM 1.8 Gy), from 41.6 (1.6) to 35.7 (1.5) Gy, and at 43 degrees C from 33.3 (1.6) to 27.3 (1.5) Gy, representing a glucose enhancement ratio of approximately 1.2. At doses corresponding to the TCD(50) at either 42 or 43 degrees C, the addition of glucose increased tumor control from 50% to 70%. An enhancement ratio of 2.1 was found for the combination of irradiation, glucose infusion, and heating at 43 degrees C, with respect to irradiation alone (TCD(50) 56.3 Gy, reanalyzed earlier data). The contribution of combined heat and glucose to tumor control represented an additive effect, probably on the hypoxic cell population. CONCLUSION: Moderate glucose administration (blood concentration 300 mg/100 mL) sizably improves experimental tumor control after combined X-irradiation and hyperthermia under clinically feasible conditions. Clinical treatment should benefit from this additional modality, in particular if unsatisfactory local control rates are due to insufficient heating. The therapeutic gain has to be evaluated further in clinical studies.
Animals↗
Equivalence of hyperfractionated and continuous brachytherapy in a rat tumor model and remarkable effectiveness when preceded by external irradiation.
PURPOSE: In clinical brachytherapy, there is a tendency to replace continuous low-dose-rate (LDR) irradiation by either single-dose or fractionated high-dose-rate (HDR) irradiation. In this study, the equivalence of LDR treatments and fractionated HDR (2 fractions/day) or pulsed-dose-rate (PDR, 4 fractions/day) schedules in terms of tumor cure was investigated in an experimental tumor model. METHODS AND MATERIALS: Tumors (rat rhabdomyosarcoma R1M) were grown s.c. in the flank of rats and implanted with 4 catheters guided by a template. All interstitial radiation treatment (IRT) schedules were given in the same geometry. HDR was given using an (192)Ir single-stepping source. To investigate small fraction sizes, part of the fractionated HDR and PDR schedules were applied after an external irradiation (ERT) top-up dose. The endpoint was the probability of tumor control at 150 days after treatment. Cell survival was estimated by excision assay. RESULTS: Although there was no fractionation effect for fractionated HDR given in 1 or 2 fractions per day, TCD(50)-values were substantially lower than that for LDR. A PDR schedule with an interfraction interval of 3 h (4 fractions/day), however, was equivalent to LDR. The combination of ERT and IRT resulted in a remarkably increased tumor control probability in all top-up regimens, but no difference was found between 2 or 4 fractions/day. Catheter implantation alone decreased the TCD(50) for single-dose ERT already by 17.4 Gy. Cell viability assessed at 24 h after treatment demonstrated an increased effectiveness of interstitial treatment, but, after 10 Gy ERT followed by 10 Gy IRT (24-h interval), it was not less than that calculated for the combined effect of these treatments given separately. CONCLUSION: In full fractionation schedules employing large fractions and long intervals, the sparing effect of sublethal damage repair may be significantly counteracted by reoxygenation. During 3-h intervals, however, repair may be largely completed with only partial reoxygenation causing PDR schedules to be less effective than fractionated HDR, and equivalent to LDR. Brachytherapy with clinically sized fractions after a large external top-up dose showed a remarkable increase in tumor control rate with no effect of fractionation (up to 4 fractions/day), which could not be fully explained by differences in dose distribution or in the cell viability assessed after treatment. This suggests a longer lasting effect on cell survival or radiosensitivity associated with catheter implantation shortly after the top-up dose.
Animals↗
Rapid decreases in donor-specific cytotoxic T lymphocyte precursor frequencies and graft outcome after liver and lung transplantation.
BACKGROUND: A decrease in donor-specific T cell precursor frequencies as seen late, one or more years, after transplantation is assumed to reflect transplantation tolerance, a condition important for long term acceptance of the allograft. However, such late decreases also occur in recipients that developed chronic transplant dysfunction questioning its relevance in transplantation tolerance. We investigated whether early, i.e., the first 6 months, decreases in donor-specific T cell precursor frequencies reflect transplantation tolerance and predict graft outcome after liver and lung transplantation. METHODS: Donor and third party specific cytotoxic (CTLp) and helper T lymphocyte precursor (HTLp) frequencies were analyzed in pretransplant and 1 (or 2) and 6-month blood samples taken from liver and lung recipients and were correlated with graft outcome. RESULTS: In liver allograft recipients with good graft function (n=7), mean donor-specific CTLp frequencies decreased as early as 1 month after transplantation and remained low thereafter. In contrast, mean CTLp frequencies did not decrease in liver allograft recipients with chronic transplant dysfunction (n=6). In lung allograft recipients, donor-specific CTLp frequencies remained relatively high and frequencies were not different between recipients without (n=6) or with (n=6) chronic transplant dysfunction. Donor-specific HTLp frequencies did not change significantly after liver or lung transplantation and did not differ between recipients without or with chronic transplant dysfunction. CONCLUSIONS: An early decrease in donor-specific CTLp correlates with good graft outcome after liver transplantation. Such rapid decreases in alloreactivity do not occur after lung transplantation illustrating the unique capacity of liver allografts to induce transplantation tolerance.
Humans↗
Increased cancer risk after liver transplantation: a population-based study.
BACKGROUND/AIMS: Development of de novo malignancies emerges as a serious long term complication after liver transplantation. METHODS: We reviewed the medical records of 174 adult one-year survivors for de novo malignancies. The observed cancer rates were compared with the expected cancer rates in the Dutch population. RESULTS: Twenty-one of the 174 patients developed 23 malignancies (12%). Skin and lip cancer accounted for 12 of the 23 malignancies (52%). Only one patient had a B-cell lymphoma. The cumulative risk for de novo malignancy was 6, 20, and 55% at 5, 10, and 15 years after transplantation, respectively. The overall relative risk (RR) as compared with the general population was 4.3 (95% confidence interval 2.4-7.1). Significantly increased RRs were observed for non-melanoma skin cancer (RR 70.0), non-skin solid cancer (RR 2.7), renal cell cancer (RR 30.0), and colon cancer (RR 12.5). Multivariate analysis showed that an age > 40 years and pretransplant use of immunosuppression were significant risk factors. CONCLUSIONS: An increased risk of cancer exists after liver transplantation, for both for skin/lip cancer, and other solid tumors. Older age and the use of immunosuppression are risk factors.
Adult↗
Tumor hypoxia--a confounding or exploitable factor in interstitial brachytherapy? Effects of tissue trauma in an experimental rat tumor model.
PURPOSE: To evaluate the potential effects of tumor hypoxia induced by afterloading catheter implantation on the effectiveness of brachytherapy in a rat tumor model. METHODS AND MATERIALS: Afterloading catheters (4) were implanted in subcutaneously growing R1M rhabdomyosarcoma in female Wag/Rij rats. A MicroSelectron (Nucletron) was used for interstitial high-dose-rate irradiation ((192)Ir). Tumor oxygenation, perfusion, and cell survival were assessed by pO(2) histography (Eppendorf), Tc-99m injection, and excision assay, respectively. RESULTS: Tumor perfusion was markedly reduced at 1 h after catheter implantation (33.9 +/- 6.0% (SEM, n = 9) of control) and partly recovered after 5 h (61.5 +/- 12.2%). At 24 h, the perfusion level reached control values (100.6 +/- 25.7%), but was highly variable with some of the tumors showing hardly any recovery at all. Tumor oxygenation showed a similar pattern, but with less recovery. Median pO(2) readings were 13.5, 1.2, and 5.3 mm Hg before and at 1 and 24 h after implantation, respectively (7 tumors). The percentages of pO(2) readings </= 2.5 mm Hg were 18.9%, 55.6%, and 41.3% at these time points. The difference in cell survival after irradiation (10 Gy) at 1 or 24 h after implantation was compatible with a radiobiological oxygen effect. CONCLUSION: Implantation of brachytherapy afterloading catheters induces an increased level of hypoxia for several hours by disrupting tumor perfusion, causing both a modest degree of direct cell kill and a significant reduction of the radiation effect. This transient hypoxia might be exploited by combining irradiation with properly timed treatments targeting hypoxic cells.
Animals↗
Bone mineral density in the long term after liver transplantation.
Hepatic osteodystrophy is a complication of chronic liver disease and bone mass is known to decline further in the first year after liver transplantation. The present study focused on bone mineral density (BMD) between 1 and 15 years after liver transplantation under a prednisolone- and azathioprine-based immunosuppressive regimen. Three groups of adult patients were studied: group 1, 45 patients with a follow-up of 5-9 years after transplantation, had BMD measurements done at 1, 2 and 5 years after transplantation; group 2, 17 patients with a follow-up of 10-14 years, had BMD measurements done at 5 and 10 years; group 3, 4 patients with a follow-up of more than 15 years, had BMD measurements done at 10 and 15 years. BMD of lumbar spine (L1-L4) and proximal femur was measured using dual-energy X-ray absorptiometry, and at the same time radiographs of the spine and hips were made. Spinal BMD increased significantly, during the second post-transplant year; subsequently no significant changes were seen. Proximal femur BMD decreased slightly, but significantly during the second year, and remained stable afterwards. About one-third of patients had a BMD below the fracture threshold (= 0.798 g/cm2 for the lumbar spine and 0.675 g/cm2 for the hip) during the follow-up. In 5 of the 66 patients studied, new vertebral fractures occurred. No fractures or avascular necrosis of the hips were seen. Furthermore, after transplantation lower Z-scores of the hip were found in patients with pre-transplant cholestatic liver diseases, and lower Z-scores of the lumbar spine were found in men compared with women. Long-term follow-up of BMD up to 15 years after transplantation revealed an improvement mainly in the second postoperative year with no deterioration afterwards. Nevertheless a substantial number of patients (around one-third) kept a BMD below the fracture threshold, and new fractures may occasionally occur. The overall outcome appeared somewhat less favorable in men and patients transplanted for cholestatic liver diseases.
Absorptiometry, Photon↗
Clinical significance of anti-neutrophil cytoplasmic antibodies (ANCA) in autoimmune liver diseases.
BACKGROUND/AIMS: The clinical relevance of anti-neutrophil cytoplasmic antibodies (ANCA) in autoimmune liver disease is unclear. Defining the antigenic specificities of ANCA in these diseases may improve their clinical significance. METHODS: We studied the target antigens of ANCA in 88 patients with autoimmune hepatitis, 53 patients with primary biliary cirrhosis, and 55 patients with primary sclerosing cholangitis by indirect immunofluorescence, antigen-specific enzyme-linked immunosorbent assays, and immunodetection on Western blot, using an extract of whole neutrophils as a substrate. We related the data to clinical symptoms of autoimmune liver disease. RESULTS: By indirect immunofluorescence, ANCA were present in 74% of patients with autoimmune hepatitis, 26% of patients with primary biliary cirrhosis, and 60% of patients with primary sclerosing cholangitis. Major antigens were catalase, alpha-enolase, and lactoferrin. The presence of ANCA as detected by indirect immunofluorescence was associated with the occurrence of relapses in autoimmune hepatitis, with decreased liver synthesis function in primary biliary cirrhosis and in primary sclerosing cholangitis, and with increased cholestasis in primary sclerosing cholangitis. ANCA of defined specificities had only limited clinical relevance. CONCLUSIONS: ANCA as detected by indirect immunofluorescence seem associated with a more severe course of autoimmune liver disease. The target antigens for ANCA in these diseases include catalase, alpha-enolase, and lactoferrin. Assessment of the antigenic specificities of ANCA in autoimmune liver disease does not significantly contribute to their clinical significance.
Adolescent↗
Single dose irradiation response of pig skin: a comparison of brachytherapy using a single, high dose rate iridium-192 stepping source with 200 kV X-rays.
An experimental brachytherapy model has been developed to study acute and late normal tissue reactions as a tool to examine the effects of clinically relevant multifractionation schedules. Pig skin was used as a model since its morphology, structure, cell kinetics and radiation-induced responses are similar to human skin. Brachytherapy was performed using a microSelectron high dose rate (HDR) afterloading machine with a single stepping source and a custom-made template. In this study the acute epidermal reactions of erythema and moist desquamation and the late dermal reactions of dusky mauve erythema and necrosis were evaluated after single doses of irradiation over a follow-up period of 16 weeks. The major aims of this work were: (a) to compare the effects of iridium-192 (192Ir) irradiation with effects after X-irradiation; (b) to compare the skin reactions in Yorkshire and Large White pigs; and (c) to standardize the methodology. For 192Ir irradiation with 100% isodose at the skin surface, the 95% isodose was estimated at the basal membrane, while the 80% isodose covered the dermal fat layers. After HDR 192Ir irradiation of Yorkshire pig skin the ED50 values (95% isodose) for moderate/severe erythema and moist desquamation were 24.8 Gy and 31.9 Gy, respectively. The associated mean latent period (+/- SD) was 39 +/- 7 days for both skin reactions. Late skin responses of dusky mauve erythema and dermal necrosis were characterized by ED50 values (80% isodose) of 16.3 Gy and 19.5 Gy, with latent periods of 58 +/- 7 days and 76 +/- 12 days, respectively. After X-irradiation, the incidence of the various skin reactions and their latent periods were similar. Acute and late reactions were well separated in time. The occurrence of skin reactions and the incidence of effects were comparable in Yorkshire and Large White pigs for both X-irradiation and HDR 192Ir brachytherapy. This pig skin model is feasible for future studies on clinically relevant multifractionation schedules in a brachytherapy setting.
Animals↗
The central role of monocytes in the pathogenesis of sepsis: consequences for immunomonitoring and treatment.
Despite important advances in critical care medicine during the last two decades, the mortality rate of sepsis has remained high, probably because the pathogenesis of sepsis is still incompletely understood. Recent studies have shown that sepsis is a bimodal entity. The first phase is characterized by the systemic release of pro-inflammatory cytokines such as tumor necrosis factor-alpha (TNF-alpha), interleukin-1 (IL-1), and IL-8, and by activation of the complement and coagulation cascades. In the second phase, anti-inflammatory mediators such as transforming growth factor-beta (TGF-beta), IL-10 and prostaglandin E2 (PGE2) may be released in an effort to counteract ongoing inflammation. Depending whether the pro- or anti-inflammatory response predominates, sepsis results in a systemic inflammatory response syndrome (SIRS), or a compensatory anti-inflammatory response syndrome (CARS). So far, most efforts to intervene in the immunopathogenesis of sepsis have been directed at the pro-inflammatory response. None of these interventions has been shown to improve the prognosis of sepsis, possibly because many patients were already in a state in which anti-inflammatory responses dominated. Recently, it has been shown that decreased expression of HLA-DR on monocytes in patients with sepsis constitutes a marker for CARS. We suggest that HLA-DR expression on monocytes might constitute a useful indicator of the immunological status of the individual patient with sepsis and a guide for treatment. Patients with CARS, as manifested by low HLA-DR expression, might benefit from immunostimulants, while patients with SIRS and normal or high monocyte HLA-DR expression should receive treatment directed to interfere with pro-inflammatory pathways.
Biomarkers↗
Low HLA-DR expression on peripheral blood monocytes predicts bacterial sepsis after liver transplantation: relation with prednisolone intake.
Bacterial sepsis remains a frequent complication after liver transplantation. We previously reported the results of a pilot study that suggested that low expression of HLA-DR on monocytes is a predictive marker for the occurrence of sepsis. We have studied the value of this marker in an additional cohort of patients, and have analyzed the relation of HLA-DR expression with the use of immunosuppressive agents. 20 adult liver transplantation patients were prospectively monitored during the first 4 weeks after transplantation. All were treated according to standard protocols. The percentage of monocytes expressing HLA-DR was measured by flow cytometry. In addition, the effects of incubation of monocytes with prednisolone in vitro on the expression of HLA-DR was determined in 7 healthy volunteers. Seven patients developed bacterial sepsis after a median 15 (range 10-20) days after transplantation. HLA-DR expression was significantly lower in these patients on days 7, 14, 21, and 28 after transplantation compared with non-septic patients. The percentage of HLA-DR positive monocytes was 30% or less, 3 (1-8) days before onset of sepsis. On day 7 after transplantation, HLA-DR expression on 50% or less of monocytes had a positive predictive value for sepsis of 71%, whereas the negative predictive value was 85%. Patients who developed sepsis received significantly more prednisolone. Incubation with prednisolone in vitro lowered the expression of HLA-DR in a dose-dependent manner. We conclude that low HLA-DR expression on monocytes is a marker for a high risk of subsequent sepsis in liver transplantation patients. This high risk may be (at least partly) related to the dose of prednisolone.
Adolescent↗
Donor-specific hyporeactivity after liver transplantation: prominent decreases in donor-specific cytotoxic T lymphocyte precursor frequencies independent of changes in helper T lymphocyte precursor frequencies or suppressor cell activity.
BACKGROUND: The development of immunological donor-specific hyporeactivity may account for the low incidence of chronic rejection after clinical liver transplantation. We investigated whether hyporeactivity commonly develops after liver transplantation by analyzing precursor frequencies of donor-reactive cytotoxic (CTLp) and helper (HTLp) T lymphocytes and mixed lymphocyte culture (MLC) reactivity in liver allograft recipients. We further studied whether CTLp hyporeactivity correlated with changes in donor-specific HTLp frequencies or suppressor cell activity. METHODS: CTLp and HTLp frequencies and MLC reactivity against donor and third-party spleen cells were determined in pre- and posttransplantation peripheral blood samples from 18 recipients with good graft function 2 years after transplantation. By mixing posttransplantation samples (with "putative" suppressor cell activity) with pretransplantation samples (in which normal CTL activity with no suppressor cell activity is expected), the presence of suppressor cell activity in peripheral blood was analyzed. RESULTS: Two years after transplantation, all but one (94%) of the recipients had developed CTLp hyporeactivity as evidenced by reduced donor-specific CTLp frequencies. The development of hyporeactivity was not specific for any particular underlying disease. The occurrence of HTL hyporeactivity, however, was less frequent: 38% and 20% of recipients were HTLp and MLC hyporeactive, respectively. Decreases in CTLp frequencies did not correlate with decreased donor-specific HTL function or suppressor cell activity in peripheral blood samples. CONCLUSIONS: Donor-specific CTLp hyporeactivity can develop in the majority of liver allograft recipients, irrespective of underlying disease. Donor-specific HTL hyporeactivity, however, occurs infrequently. A reduction in donor-specific CTLp frequencies was found to be independent of changes in donor-specific HTLp or suppressor cell activity, suggesting that other mechanisms (e.g., clonal deletion) are operative in the reduction of donor-specific CTLp after liver transplantation.
Humans↗
Expression of p53, p21/WAF/CIP, Bcl-2, Bax, Bcl-x, and Bak in radiation-induced apoptosis in testicular germ cell tumor lines.
PURPOSE: Testicular germ cell tumors (TGCTs) represent one of the few tumor types that are curable by antineoplastic therapy, probably due to the high sensitivity of this neoplasm to induction of apoptosis by chemotherapeutic agents and/or ionizing radiation. Here, we tested cell susceptibility to radiation-induced apoptosis in a panel of TGCT cell lines and attempted to correlate this with the known potentially relevant molecular determinants (p53 gene status and Bcl-2 family proteins) of apoptosis. METHODS AND MATERIALS: Induction of apoptosis by gamma-radiation was morphologically recognized in NT2, NCCIT, S2, and 2102 EP using Hoechst/PI staining and additionally confirmed by Western blot analysis of PARP cleavage. The p53 gene status was estimated by sequence analysis. Expression of p21/WAF/CIP was determined by Northern blot analysis and immunoblotting was used to monitor p53, Bax, Bcl-2, Bcl-x, and Bak protein levels. In vitro colony formation was studied to establish clonogenic survival curves. RESULTS: NT2 and NCCIT appeared to be susceptible for radiation-induced apoptosis, contrasting 2102 EP and S2 which were highly resistant. Sequence analysis showed that NT2, S2, and 2102 EP are homozygous for wild-type p53 (wtp53), whereas NCCIT contains mutant p53 (mtp53). NT2 and 2102 EP cells showed radiation-induced p53 upregulation, while NCCIT (mtp53) and S2 (no p53 protein) cells did not. Consistently, gamma-radiation-induced DNA damage resulted in a p53-dependent transactivation of the p21/WAF/CIP gene in NT2 and 2102 EP, but not in mtp53-containing NCCIT cells and p53 nonexpressing S2 cells. Constitutive expression of Bax, Bcl-2, Bcl-x, and Bak was not affected by radiation and showed no correlation with cell susceptibility to radiation-induced apoptosis. A discrepancy was found between apoptosis and reproductive death. CONCLUSIONS: The present study revealed that: i) the presence of wtp53 may not be absolutely required for the hypersensitivity for radiation-induced apoptosis in TGCT cell lines, ii) the molecular mechanism underlying the unique radiosensitivity was independent of the expression of Bcl-2 family proteins, and iii) cell susceptibility to apoptosis induction is not sufficiently informative to predict intrinsic radiosensitivity as determined by clonogenic survival.
Apoptosis↗
Quantitation of immunosuppression by flow cytometric measurement of the capacity of T cells for interleukin-2 production.
BACKGROUND: Methods to quantitate the effects of immunosuppressive drugs on immune reactivity might be helpful for monitoring immunosuppressive treatment. Cyclosporine (CsA) inhibits the induction of cytokine synthesis in T cells, and measurement of interleukin (IL)-2 production might constitute a parameter of this drug's effect. METHODS: We determined the percentages of CD4+ and CD8+ lymphocytes producing IL-2 upon stimulation by phorbol myristate acetate and calcium ionophore in whole blood culture, using immunostaining of intracytoplasmatic and membrane markers, followed by multiparameter flow cytometry. A total of 38 clinically stable transplant patients on various immunosuppressive protocols were studied. RESULTS: The percentage of CD4+ T cells producing IL-2 was strongly reduced in patients compared with healthy controls (23% [range, 3-68%] vs. 59.0% [range, 41-70%]; P=0.000035). The percentage of CD4+ T cells producing IL-2 was negatively correlated with the CsA level (Rc=-0.0821, P=0.00002297) but not with prednisolone or azathioprine doses. Fewer CD8+ T cells produced IL-2 in transplant patients compared with controls, but the difference failed to reach statistical significance. The percentage of CD8+ T cells capable of producing IL-2 was inversely correlated to CsA levels (Rc=-0.0375, P=0.0011). CONCLUSIONS: These data suggest that the functional effects of CsA in transplant recipients can be quantitatively determined and that the capacity of CD4+ T cells to produce IL-2 upon stimulation constitutes a functional parameter of CsA effects on the immune system. Prospective studies are required to determine whether this method is useful for clinical monitoring.
Adult↗