Regulation of cellular iron metabolism by erythropoietin: activation of iron-regulatory protein and upregulation of transferrin receptor expression in erythroid cells

Erythropoietin (Epo) is the central regulator of red blood cell production and acts primarily by inducing proliferation and differentiation of erythroid progenitor cells. Because a sufficient supply of iron is a prerequisite for erythroid proliferation and hemoglobin synthesis, we have investigated whether Epo can regulate cellular iron metabolism. We present here a novel biologic function of Epo, namely as a potential modulator of cellular iron homeostasis. We show that, in human (K562) and murine erythroleukemic cells (MEL), Epo enhances the binding affinity of iron-regulatory protein (IRP)-1, the central regulator of cellular iron metabolism, to specific RNA stem-loop structures, known as iron-responsive elements (IREs). Activation of IRP-1 by Epo is associated with a marked increase in transferrin receptor (trf-rec) mRNA levels in K562 and MEL, enhanced cell surface expression of trf-recs, and increased uptake of iron into cells. These findings are in agreement with the well-established mechanism whereby high-affinity binding of IRPs to IREs stabilizes trf-rec mRNA by protecting it from degradation by a specific RNase. The effects of Epo on IRE-binding of IRPs were not observed in human myelomonocytic cells (THP-1), which indicates that this response to Epo is not a general mechanism observed in all cells but is likely to be erythroid-specific. Our results provide evidence for a direct functional connection between Epo biology and iron metabolism by which Epo increases iron uptake into erythroid progenitor cells via posttranscriptional induction of trf-rec expression. Our data suggest that sequential administration of Epo and iron might improve the response to Epo therapy in some anemias.

Modulatory potential of iron chelation therapy on nitric oxide formation in cerebral malaria

To determine whether iron chelation modulates nitric oxide (NO) formation and cell-mediated immune effector function in children with cerebral malaria, serum concentrations were measured of the stable end products of NO, nitrite and nitrate (NO2-/NO3-), interleukin (IL)-4, -6, and -10, and neopterin in 39 Zambian children enrolled in a placebo-controlled trial of desferrioxamine B and quinine therapy. Mean concentrations of NO2-/NO3- increased significantly over 3 days in children receiving desferrioxamine plus quinine but not in those given placebo and quinine. Neopterin levels declined significantly with placebo but not with desferrioxamine. IL-4 levels increased progressively in the placebo group and ultimately decreased in the desferrioxamine group, but the trends were not statistically significant. IL-6 and IL-10 levels were elevated initially and decreased significantly in both groups over 3 days. These data are consistent with the hypothesis that iron chelation therapy in children with cerebral malaria strengthens Th1-mediated immune effector function involving increased production of NO.

[Cellular and humoral functions in acute pancreatitis]

Infectious complications are the leading cause of death in acute pancreatitis. Individual factors of immune defence could be of significance, whether or not a patient develops a severe course with infectious complications. In a prospective 5-year trial including 72 patients, we investigated 29 cellular and humoral markers of the body's defence system for their potential to indicate the severity and course of acute pancreatitis. Complement factors C3 and C4 as well as immunoglobulins IgG, IgM and IgA were normal, in general. Measurable levels of IL-1 alpha, IL-1 beta, IL-2 and sIL-2R could be detected only occasionally. Values of alpha 1-AT, TNF-alpha, TNF alpha-Rp75, neopterin, sICAM-1, IL-8, IL-1RA and sIL-6R did not correlate with a severe course. Due to the high magnitude of increase, CRP, IL-6 and granulocyte elastase were the best indicators of the inflammatory process. Delayed-type hypersensitivity response was the only early predictor of a severe course. It was superior over other cellular markers such as monocyte count or CD4+/CD8+ ratio. In vitro function of polymorphonuclear granulocytes (PMN) was not adequate to the severity of the disease already during the first week of illness. During further course, PMN motility and capacities to produce reactive oxygen species even worsened. The compromized PMN function could explain the frequent development of infectious complications in patients suffering from severe pancreatitis. These results should encourage new concepts of infection prophylaxis using stimulants of cellular defence.

Patterns of hepatitis C viremia in patients receiving hemodialysis

OBJECTIVES

Chronic hepatitis C virus (HCV) infection is common in patients who receive hemodialysis (HD). The aim of this study was to determine the natural history of hepatitis C viremia and the clinical utility of quantitation and genotyping of HCV in this population of patients.

METHODS

Consecutive sera from two groups of HD patients who were HCV RNA positive, a group of 33 patients treated with interferon alfa (5 MU, three times a week for 4 months) and a group of 31 untreated patients, were analyzed by qualitative polymerase chain reaction, quantitative polymerase chain reaction, and a line probe assay for genotyping.

RESULTS

Serum HCV RNA was detected continuously in 20 of 31 untreated patients (65%), and 11 patients (35%) showed a fluctuating pattern of viremia with virus-free intervals of up to 4 wk. Twenty-five of 33 patients (76%) treated with interferon alfa became HCV RNA negative during therapy; eight of these 25 patients had a breakthrough, which was transient in seven patients and persistent in one. Of the remaining 24 end-of-treatment responders, 17 relapsed after completion of therapy, and seven (21%) had a sustained response with undetectable serum HCV RNA for 1 yr of follow-up. Initial serum HCV RNA levels in HD patients were generally low (median, 1 x 10(5) genome eq/ml). Sustained responders had significantly lower median levels of viremia (4 x 10(4) eq/ml) than relapsers and nonresponders (9 x 10(4) and 1.8 x 10(5) eq/ml, respectively). Genotyping revealed a predominance of genotype 1a (33%) and 1b (48%).

CONCLUSIONS

This study documents that fluctuating hepatitis C viremia with periods of undetectable HCV RNA is common and that low viral load predicts a sustained response to interferon therapy in HD patients. Diagnosis of chronic hepatitis C and monitoring of interferon therapy in HD patients should include initial HCV RNA quantitation and repeated qualitative measurements of HCV RNA.

Pathways for the regulation of macrophage iron metabolism by the anti-inflammatory cytokines IL-4 and IL-13

Macrophage effector functions are influenced by their iron status and by shifts in the balance between type 1 Th1 and Th2 cells. To elucidate the influence of the Th2 cytokines IL-4 and IL-13 on macrophage iron metabolism, we investigated activated primary mouse macrophages and the murine macrophage cell line J774. Stimulation of J774 cells and primary macrophages with IFN-gamma/LPS activates the RNA binding affinities of iron regulatory protein-1 (IRP-1) and IRP-2 for iron-responsive elements, leading to translational repression of the iron storage protein ferritin. Activation of IRP-1 and IRP-2 is caused by increased formation of nitric oxide (NO) via stimulation of the inducible NO synthase by IFN-gamma/LPS. Treatment of macrophages with IL-4 and/or IL-13 before stimulation with IFN-gamma/LPS suppresses NO formation and IRP activation, with concomitantly enhanced ferritin synthesis despite a small reduction in ferritin heavy chain mRNA levels. The mRNA levels for the membrane receptor for iron uptake, transferrin receptor (TfR), decrease following stimulation with IFN-gamma/LPS, although IRP-mediated stabilization of the TfR mRNA would have been expected. This as yet unidentified proximal inhibitory signal by IFN-gamma/LPS is antagonized by IL-4 and/or IL-13, which leads to increased TfR mRNA expression in an IRP-independent manner. Thus, IL-4 and IL-13 regulate the iron metabolism of activated macrophages by at least two different pathways: first, by opposing NO-mediated IRP activation, thereby increasing ferritin translation; and second, by an IRP-independent augmentation of TfR mRNA expression. We suggest that IL-4 and IL-13 may enhance iron uptake and storage in activated macrophages and thereby contribute to down-regulation of macrophage effector functions.

Uterus didelphis with obstructed hemivagina and ipsilateral renal agenesis: ultrasound and magnetic resonance imaging diagnosis

The association of uterus with unilateral imperforate hemivagina and ipsilateral renal agenesis is extremely rare. We present a case of a 13-year-old virginal patient in whom a combination of intravenous pyelogram and ultrasound was comparable to magnetic resonance imaging in permitting an accurate preoperative diagnosis thus allowing for early and appropriate surgical intervention and possible preservation of fertility.

Pathways for the regulation of macrophage iron metabolism by the anti-inflammatory cytokines IL-4 and IL-13

Macrophage effector functions are influenced by their iron status and by shifts in the balance between type 1 Th1 and Th2 cells. To elucidate the influence of the Th2 cytokines IL-4 and IL-13 on macrophage iron metabolism, we investigated activated primary mouse macrophages and the murine macrophage cell line J774. Stimulation of J774 cells and primary macrophages with IFN-gamma/LPS activates the RNA binding affinities of iron regulatory protein-1 (IRP-1) and IRP-2 for iron-responsive elements, leading to translational repression of the iron storage protein ferritin. Activation of IRP-1 and IRP-2 is caused by increased formation of nitric oxide (NO) via stimulation of the inducible NO synthase by IFN-gamma/LPS. Treatment of macrophages with IL-4 and/or IL-13 before stimulation with IFN-gamma/LPS suppresses NO formation and IRP activation, with concomitantly enhanced ferritin synthesis despite a small reduction in ferritin heavy chain mRNA levels. The mRNA levels for the membrane receptor for iron uptake, transferrin receptor (TfR), decrease following stimulation with IFN-gamma/LPS, although IRP-mediated stabilization of the TfR mRNA would have been expected. This as yet unidentified proximal inhibitory signal by IFN-gamma/LPS is antagonized by IL-4 and/or IL-13, which leads to increased TfR mRNA expression in an IRP-independent manner. Thus, IL-4 and IL-13 regulate the iron metabolism of activated macrophages by at least two different pathways: first, by opposing NO-mediated IRP activation, thereby increasing ferritin translation; and second, by an IRP-independent augmentation of TfR mRNA expression. We suggest that IL-4 and IL-13 may enhance iron uptake and storage in activated macrophages and thereby contribute to down-regulation of macrophage effector functions.

Pharmacokinetic characteristics of a new liquid sustained-release formulation of theophylline designed for the elderly and children: microcaps as sachet

A new sustained-release theophylline formulation was especially designed for the elderly and children. Microcapsules of theophylline, administered as a suspension in water, proved to be a suitable dosage form for a clientele with impaired or difficult deglutition. Pharmacokinetic characteristics of 2 batches at the lower (T1) and the upper (T2) in vitro dissolution specification range of this new formulation and a pellet formulation (R) as a comparator were evaluated in an open, randomized, 3-way, multiple-dose, crossover study design with an asymmetric dosage regimen of 400 mg and 200 mg theophylline. Smooth and safe plasma concentrations with a high and long-lasting plateau were achieved with this new formulation. Plateau times which are independent of the asymmetric dosage regimen ranged from 16.4 hours (T1) to 13.8 hours (T2) and could therefore span sufficient time of the dosage interval. Maximum serum levels of 9.6 micrograms/ml and 10.0 micrograms/ml were attained 6.6 and 6.1 hours after dosing of T1 and T2, coinciding perfectly with the time of the critical morning dip at 2-4 a.m. With a nocturnal excess of 15.5% (T1) and 17.9% (T2) this circadian-tailored asymmetric dosage regimen proved to take into account the chronopathology of asthma and the chronopharmacokinetics of theophylline sustained-release preparations. Bioequivalence of all 3 formulations versus each other with regard to rate (Cmaxss) and extent (AUC(tau)ss) of absorption could be established for the 2 batches at the upper and lower in vitro specification range and for both batches of the new formulation compared to the reference. All in all, safety and efficacy of this new liquid prolonged-release theophylline could be established. Furthermore, in vitro specifications could be justified according to current EU guidelines.

Divergent effects of alpha 1-antitrypsin on the regulation of iron metabolism in human erythroleukaemic (K562) and myelomonocytic (THP-1) cells

The acute-phase protein alpha 1-antitrypsin (alpha 1-AT) has been shown to inhibit the binding of transferrin to its cell-surface receptor. Here we demonstrate that in human erythroleukaemic cells (K562) alpha 1-AT enhances the binding affinity of iron-regulatory protein (IRP), the central regulator of cellular iron metabolism, to iron-responsive elements. Activation of IRP by alpha 1-AT is associated with a marked increase in transferrin receptor (trf-rec) mRNA levels in K562 and enhanced cell-surface expression of transferrin-binding sites, whereas ferritin production is decreased, although ferritin mRNA levels remain unchanged. In agreement with the well-established mechanism of cellular iron regulation, alpha 1-AT seems to modulate trf-rec and ferritin expression primarily post-transcriptionally/translationally by influencing IRP activity. In contrast, alpha 1-AT produces only minor changes in IRP activity, and subsequently in trf-rec expression and ferritin synthesis in THP-1 cells. Moreover the effects of alpha 1-AT on iron homeostasis in K562 cannot be overcome by the addition of iron salts, whereas concomitant treatment of THP-1 with iron and alpha 1-AT results in the same metabolic changes as the addition of iron alone. Because alpha 1-AT blocks transferrin binding on K562 as well as on THP-1 cells, it is suggested, on the basis of the results presented here, (1) that erythroid and monocytic cells might differ in their dependence on transferrin-mediated iron supply and (2) that THP-1 might be able to acquire iron by a transferrin-independent iron uptake system. alpha 1-AT might therefore be involved in the diversion of iron traffic between various cellular compartments under inflammatory conditions.

Helicobacter pylori infection and blood group antigens: lack of clinical association

OBJECTIVES

Blood group antigens traditionally have been associated with a risk of developing peptic ulcer and gastric cancer. Helicobacter pylori is a bacterium associated with chronic active gastritis and ulcer disease, and its attachment to gastric mucosa was recently shown in vitro to be mediated by blood group Lewisb and H antigens. This study was designed to test the clinical relevance of this laboratory observation in patients undergoing endoscopy and gastric biopsy.

METHODS

Blood group phenotypes and gastric biopsies for H. pylori and histology were determined and correlated in 384 patients undergoing upper endoscopy. Blood from healthy blood donors was tested for the same blood group antigens and used as a control group.

RESULTS

The distribution of blood groups ABO, Lewis, Rhesus, and MN was similar among the patients undergoing endoscopy and a control group of 2369 healthy blood donors from the same geographic area. There was no correlation between H. pylori infection or the H. pylori-associated diseases, peptic ulcer or chronic active gastritis, with any blood group phenotype, including Lewisb, blood group O, or both.

CONCLUSION

No in vivo correlation between H. pylori infection or disease and Lewisb or H antigen could be demonstrated. Moreover, patients with H. pylori infection and disease have a distribution of blood group antigens similar to a control population.

Gonadotropin-releasing hormone agonist and human menopausal gonadotropin (hMG) short protocol, but not hMG alone, rescues the corpus luteum from the preceding cycle

OBJECTIVE

To determine whether ovulation induction regimens, particularly the short protocol, has an effect on the corpus luteum (CL) from the previous cycle.

DESIGN

Infertility patients were followed in an academic research environment. Patients were treated with either the short protocol (GnRH agonist [GnRH-a] and hMG) or hMG alone in a controlled ovarian hyperstimulation cycle.

SETTING

Infertility center in academic setting.

PATIENTS

Patients requiring ovulation induction.

INTERVENTIONS

The blood samples were drawn on day 2 or 3 as a baseline before initiation of any treatments, generally on day 5 and usually every other day thereafter until ovulation. Serum P, E2, and relaxin were determined.

MAIN OUTCOME MEASURES

Serum P, E2 and relaxin.

RESULTS

Patients receiving hMG alone showed no change in serum P levels in the first few days of treatment whereas most short-protocol patients (18/30; 60%) showed an increase of P within 3 days of the initiation of treatment. The increase in P almost always was associated with an increase in relaxin as a marker of the luteal production of this P.

CONCLUSION

The short protocol with its flare of gonadotropins is able to stimulate the CL from the previous cycle, resulting in an early increase in P that comes from the CL as indicated by its association with an increased relaxin in the same subjects.

mtDNA sequence diversity in Africa

mtDNA sequences were determined from 241 individuals from nine ethnic groups in Africa. When they were compared with published data from other groups, it was found that the !Kung, Mbuti, and Biaka show on the order of 10 times more sequence differences between the three groups, as well as between those and the other groups (the Fulbe, Hausa, Tuareg, Songhai, Kanuri, Yoruba, Mandenka, Somali, Tukana, and Kikuyu), than these other groups do between one other. Furthermore, the pairwise sequence distributions, patterns of coalescence events, and numbers of variable positions relative to the mean sequence difference indicate that the former three groups have been of constant size over time, whereas the latter have expanded in size. We suggest that this reflects subsistence patterns in that the populations that have expanded in size are food producers whereas those that have not are hunters and gatherers.

A phase I clinical and pharmacokinetic study of the angiogenesis inhibitor, tecogalan sodium

BACKGROUND

Tecogalan sodium is an angiogenesis inhibitor isolated from a sulfated polysaccharide produced by the bacterium Arthrobacter. The antiangiogenic effect of tecogalan sodium is thought to be mediated by the inhibition of binding of basic fibroblast growth factor to cellular receptors.

PATIENTS AND METHODS

A phase I study was conducted in thirty-three patients with refractory malignancies, including AIDS-associated Kaposi's sarcoma. Patients received a single i.v. infusion every three weeks with the infusion duration ranging from one to twenty-four hours. Seven different dosage levels were studied (125, 185, 240, 300, 390, 445, and 500 mg/m2).

RESULTS

The primary dose-limiting toxicity was prolongation of the activated partial thromboplastin time with peak times being between 1.0-4.0 times the upper limit of normal. This toxicity was ameliorated at a given dose level by prolonging the infusion time. Other common toxicities included fever (40%) and rigors (31%) which were well controlled with acetominophen and meperidine. The serum half-life of tecogalan sodium was between 1-1.5 hours and < 25% of unchanged drug was excreted in the urine.

CONCLUSIONS

The recommended phase II dose of tecogalan sodium on this schedule is 390 mg/m2 over 24 hours. Other schedules including continuous administration should be investigated to maximize the efficacy of this novel angiogenesis inhibitor.

Nitric oxide and oxidative stress (H2O2) control mammalian iron metabolism by different pathways

Several cellular mRNAs are regulated posttranscriptionally by iron-responsive elements (IREs) and the cytosolic IRE-binding proteins IRP-1 and IRP-2. Three different signals are known to elicit IRP-1 activity and thus regulate IRE-containing mRNAs: iron deficiency, nitric oxide (NO), and the reactive oxygen intermediate hydrogen peroxide (H2O2). In this report, we characterize the pathways for IRP-1 regulation by NO and H2O2 and examine their effects on IRP-2. We show that the responses of IRP-1 and IRP-2 to NO remarkably resemble those elicited by iron deficiency: IRP-1 induction by NO and by iron deficiency is slow and posttranslational, while IRP-2 induction by these inductive signals is slow and requires de novo protein synthesis. In contrast, H2O2 induces a rapid posttranslational activation which is limited to IRP-1. Removal of the inductive signal H2O2 after < or = 15 min of treatment (induction phase) permits a complete IRP-1 activation within 60 min (execution phase) which is sustained for several hours. This contrasts with the IRP-1 activation pathway by NO and iron depletion, in which NO-releasing drugs or iron chelators need to be present during the entire activation phase. Finally, we demonstrate that biologically synthesized NO regulates the expression of IRE-containing mRNAs in target cells by passive diffusion and that oxidative stress endogenously generated by pharmacological modulation of the mitochondrial respiratory chain activates IRP-1, underscoring the physiological significance of NO and reactive oxygen intermediates as regulators of cellular iron metabolism. We discuss models to explain the activation pathways of IRP-1 and IRP-2. In particular, we suggest the possibility that NO affects iron availability rather than the iron-sulfur cluster of IRP-1.

Serum neopterin, interleukin-4, and interleukin-6 concentrations in cerebral malaria patients and the effect of iron chelation therapy

To determine if iron chelation therapy alters immune responses in children with cerebral malaria, we retrospectively measured mean serum levels of neopterin, interleukin-4 (IL-4), and IL-6 in children who received desferrioxamine B or placebo for three days in addition to quinine-based therapy. Mean levels of neopterin, IL-4, and IL-6 were elevated above the expected normal range on admission. Neopterin correlated significantly with the degree of anemia, IL-4 with the duration of fever prior to admission, and IL-6 with parasite density. Serial measurements of cytokines and neopterin were performed over four days in 39 children, 21 randomized to receive desferrioxamine B and 18 to receive placebo. Mean concentrations of neopterin did not change significantly in either group while levels of IL-4 increased significantly in the placebo group (P = 0.04) but remained unchanged in the desferrioxamine B group. Interleukin-6 concentrations decreased markedly in both groups (P < 0.025). Stable IL-4 levels in children given desferrioxamine B may represent an inhibition of the T helper lymphocyte-2 (TH-2) response resulting from a strengthened TH-1 response associated with iron chelation therapy. Any effect of iron chelation on immunity in the setting of severe malaria will have to be confirmed in future prospective investigations.

Relaxin secretion in in vitro fertilization pregnancies

OBJECTIVE

This study was designed to determine whether the late luteal functional status of the corpora lutea in in vitro fertilization cycles alters the secretion of relaxin during pregnancy.

STUDY DESIGN

Analysis of serum relaxin, human chorionic gonadotropin, and steroid concentrations in sera of women with pregnancies viable beyond the twelfth week as a result of in vitro fertilization treatment was performed.

RESULTS

The serum estradiol and progesterone concentrations decreased 5.5- and 4-fold from days 5 to 6 after human chorionic gonadotropin to days 11 to 13 after human chorionic gonadotropin, respectively. The serum relaxin concentration increased 8-fold between the 11- to 15-day interval and the 16- to 50-day interval after human chorionic gonadotropin and another 6-fold to the 51- to 90-day interval after human chorionic gonadotropin (all p < 0.01). Multiple linear regression analysis showed that the serum estradiol level 11 to 13 days after human chorionic gonadotropin and the serum human chorionic gonadotropin level 11 to 15 days after human chorionic gonadotropin were the most powerful paired predictors of the concentration of serum relaxin measured in the 11- to 15-day interval after human chorionic gonadotropin interval (R2 = 0.39, n = 50), the 16- to 50-day interval (R2 = 0.61, n = 51), and the 51- to 90-day interval (R2 = 0.55, n = 39).

CONCLUSION

Secretion of relaxin is determined by an interaction of the late luteal functional status of the corpora lutea and the human chorionic gonadotropin secreted by the implanting pregnancy. These data allow for the hypothesis that inducing functional luteolysis by substituting one or more injections of luteinizing hormone for the human chorionic gonadotropin injection may decrease secretion of steroids, relaxin, and other factors from the corpora lutea during pregnancy, decreasing the risk of premature delivery in multiple gestations and the ovarian hyperstimulation syndrome.

The effect of ovulation induction on the concentration of maternal serum relaxin in twin pregnancies

OBJECTIVE

Our purpose was to determine the effects of fetal number, various ovulation induction treatments, and placental hormones on the concentration of maternal serum relaxin.

STUDY DESIGN

The concentrations of relaxin, human chorionic gonadotropin, estriol, and alpha-fetoprotein were determined in blood samples drawn at 16 to 18 weeks for prenatal diagnosis in 72 singleton and 115 twin pregnancies and analyzed by one-way analysis of variance, correlation analysis, and stepwise multiple linear regression of the log-transformed data.

RESULTS

The maternal serum concentrations of each of the four measured hormones were significantly higher in the twin pregnancies than in the singleton pregnancies: 1.4-fold for relaxin, 1.9-fold for human chorionic gonadotropin, 1.9-fold for estriol, and 2.2-fold for alpha-fetoprotein (all p < 0.01). The concentrations of each of the four hormones were significantly correlated with each of the others and with the number of fetuses (p < 0.01), except that estriol was not significantly correlated with human chorionic gonadotropin. The serum relaxin concentration in twin pregnancies after treatment with follicle-stimulating hormone and luteinizing hormone (menotropins) (n = 10) was 3.3-fold that in twins resulting from spontaneous ovulation (n = 89, p < 0.01). In twins resulting from in vitro fertilization or gamete intrafallopian transfer (n = 9) the serum relaxin concentration was 2.6-fold higher than in twins resulting from spontaneous ovulation (p < 0.01). The effect of clomiphene citrate (1.2-fold, n = 7) failed to reach statistical significance.

CONCLUSIONS

The second fetus causes a 1.4-fold increase in the concentration of maternal serum relaxin in twin pregnancies. Induction of ovulation with menotropins causes an additional 3.3-fold increase, whereas in vitro fertilization or gamete intrafallopian transfer treatment causes an additional 2.6-fold increase over that seen in twin pregnancies that followed spontaneous ovulation.

p53, Ki-ras, and DNA ploidy in human pancreatic ductal adenocarcinomas

Ki-ras mutations and DNA aneuploidy are common findings in human pancreatic ductal adenocarcinomas. An altered p53 tumor-suppressor gene has been suggested to cooperate with activated Ki-ras in malignant cellular transformation and could enhance genomic instability. We have investigated a panel of well-documented pancreatic carcinomas with defined ploidy and Ki-ras mutations for the presence and pattern of genetic alterations of the p53 gene, their coincidence with Ki-ras point mutations, and their correlation with DNA ploidy, tumor pathology, and clinical course. DNA was isolated from formalin-fixed and paraffin-embedded tumor tissue and polymerase-chain-reaction-amplified fragments of the p53 gene exons 5 to 9 were screened by the single-strand conformation polymorphism method. The positive cases were further examined for mutations by direct sequencing. Twenty-nine of seventy-one (41%) tumors showed mutations of the p53 gene, however, five tumors carried two mutations resulting in a total of 34/71 (48%) genetic alterations of the p53 gene. The majority were missense point mutations and distributed primarily within the evolutionary conserved domains (62%). Ten of Thirty-four (29%) affected the hotspot codons 248, 273, and 282, respectively, and 21/34 (62%) of the p53 gene mutations clustered on exons 7 and 8. Transitions (71%) predominated over transversions (15%), deletions were identified in 7/34 (21%) tumors. One third of the carcinomas showed both Ki-ras codon 12 and p53 gene mutations. p53 mutations correlated with distant metastasis (p < 0.05) and survival (p < 0.05). DNA triploidy was associated with a mutated Ki-ras gene (p < 0.05) as well as with double mutations of c-Ki-ras and p53 (p < 0.05). Unlike most other malignant tumors pancreatic ductal adenocarcinomas exhibit a significantly higher incidence of c-Ki-ras than p53 gene mutations. However, like other neoplasms p53 gene mutations seem to be associated with a metastatic phenotype possibly acquired during tumor progression.

Nitric oxide formation as predictive parameter for acute graft-versus-host disease after human allogeneic bone marrow transplantation

Due to the accumulation of evidence concerning a putative role of nitric oxide (NO) in graft-versus-host disease (GVHD), we performed follow-up measurements of the stable end-products of NO, nitrite/nitrate (NO2-/NO3-) in plasma of patients undergoing allogeneic (n = 16) and autologous (n = 6, as a control) bone marrow transplantation. NO2-/NO3- concentrations were set in relation to the clinical course and to serum levels of soluble tumor necrosis factor receptor 75 (sT-NFrec 75) and neopterin, both of which are known to be sensitive indicators of cellular immune activation phenomena involving macrophages in vivo, and endogenous interleukin (IL)-10, a major T helper cell type 2 (TH-2)-derived cytokine and potent inhibitor of macrophage activation and NO formation. A significant rise of NO2-/NO3- levels was observed in patients with GVHD and preceded the onset of clinical symptoms by up to 3 days. In contrast to indicators of macrophage activation, i.e., neopterin and sT-NFrec75, NO2-/NO3- concentrations were not significantly altered from baseline levels during infectious complications, as NO2-/NO3- concentrations did not fluctuate in patients after autologous engraftment. During episodes of acute GVHD, NO2-/NO3- concentrations showed a strong positive correlation with levels of plasma neopterin and sTNFrec 75, but were also significantly related to IL-10. In non-GVHD patients, a negative correlation between IL-10 and NO2-/NO3- concentrations was evident. Therefore, NO2-/NO3- determination may be a valuable early indicator of the initiation of human GVHD. Our results provide some further insights concerning cytokine-related metabolic changes in the course of human GVHD in vivo which may prove useful in the development of new therapeutic approaches for this disease.

Predictive value of urinary neopterin in patients with lung cancer

Concentrations of neopterin, which is produced by human monocytes/macrophages when stimulated by gamma-interferon, were measured in urine specimens from 72 patients with lung cancer at diagnosis. Other routine clinical and laboratory variables were concomitantly determined. Neither neopterin nor any other laboratory variable studied showed a significant correlation with clinical indicators of the disease (morphologic type, tumour stage, grading, lymph node status, presence of distant metastases). The cancer patients were followed up for up to 10 years, and the abilities of all variable to predict fatal outcome were assessed. In univariate survival analyses, all clinical indicators except morphologic type (P = 0.86) were significant predictors of survival (P < 0.002), but of all the laboratory variables studies, only neopterin was significantly predictive (P = 0.0013). By multivariate survival analysis, a combination of four variables was found to jointly predict survival: lymph node status (P = 0.003), multivariate model), tumour stage (P = 0.0006), grading (P = 0.0047) and neopterin (P = 0.0047). The data suggest that certain aspects of immune activation may have adverse consequences for the prognosis of patients with lung cancer.