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At least 19 recordsLinked to original sources
PubMed1989

Urinary neopterin concentrations vs total neopterins for clinical utility.

Neopterin measurements are especially useful as an early marker in (e.g.) allograft rejections and in patients infected with human immunodeficiency virus type 1 (HIV-1). An increased concentration of total neopterins (neopterin + dihydroneopterin) is also a significant marker in patients with HIV-1 infection. In this study we compared concentrations of neopterin and total neopterins in urine samples from 77 homosexual men with and 73 without established HIV-1 infection. HIV-1-seropositive homosexual men had higher concentrations of neopterin and total neopterins (and 7,8-dihydroneopterin) in their urine than did those who were HIV-1-seronegative, and there was a close correlation between neopterin and total neopterins. Both neopterin variables correlated inversely with CD4+ T-cell counts and CD4+/CD8+ T-cell ratios but not with CD8+ T-cell counts in the HIV-1-seropositive men. Our data indicate that measurements of neopterin and total neopterins are of almost equal potential for clinical diagnosis. However, when measuring total neopterins, which includes oxidation of 7,8-dihydroneopterin to neopterin, more strict requirements of sample collection and handling are necessary to avoid degradation of the 7,8-dihydro derivative.

Acquired Immunodeficiency Syndrome↗
PubMed1986

Neopterin as tumour marker serum and urinary neopterin concentrations in malignant diseases.

Serum and urinary neopterin concentrations were measured in 142 patients suffering from various malignant diseases. Increased serum and urinary neopterin levels were found in 48% and 55% of patients respectively. Neopterin showed sufficient sensitivity in the detection of haematological disorders and hypernephroma, whereas the sensitivity of neopterin was rather poor in patients with other solid tumours. Comparison of serum alpha-fetoprotein (AFP) and human chorionic gonadotropin (HCG) concentrations and serum or urinary neopterin levels in testicular cancer patients showed that determination of neopterin provides no further information in the management of these patients. In testicular cancer patients receiving adjuvant chemotherapy, a significant increase in serum (p less than 0.005) and urinary (p less than 0.0005) neopterin concentrations was measured after chemotherapy, reflecting the release of neopterin from macrophages during the damage by cytotoxic drugs. In the adjuvant testicular tumour patients, known to be tumour free, 1 out of 16 patients showed elevated serum and 3 out of 15 patients showed false positive urinary neopterin levels. False positive serum (24%) and urinary (37%) neopterin values were also obtained in 28 patients with various nonmalignant diseases, but no evidence for an inflammatory process. In 23 patients with inflammatory diseases pathological serum and urinary neopterin levels were measured in 55% and 59% respectively. When a RIA was compared with a HPLC method, higher urinary neopterin values were obtained with the RIA, indicating that non-oxidized pterines are also determined by the RIA method. In conclusion, neopterin might be a helpful biological marker in monitoring patients with malignant haematological disorders and renal cell carcinoma, but provides no additional information in other solid tumours studied.

Adolescent↗
PubMed1990

Interleukin-2 and neopterin-induced neopterin release from peripheral blood mononuclear cells.

Stimulation of peripheral blood mononuclear cells (PBMC) by the mitogenic lectins, phytohaemagglutinin (PHA) and concanavalin A (conA), the lymphokine gamma-interferon (gamma-IFN) and interleukin-2 (IL-2) and the pterin neopterin, caused an increased release of neopterin from those cells, with peak levels after 7 days of stimulation. In contrast to gamma-IFN, IL-2 and neopterin failed to induce neopterin release from purified macrophages. IL-2- and neopterin-induced release of neopterin from PBMC is not dependent on proliferation and is partially inhibited by the addition of anti gamma-IFN or anti IL-2 receptor. Neopterin autoinductive production can explain the amplificated neopterin release during activation of the cellular-mediated immune response (CMI), in spite of the decrease in the T helper cell subsets, which are the main gamma-IFN producers.

Biopterins↗
PubMed1988

Comparison of serum neopterin levels and urinary neopterin excretion in renal allograft recipients.

Determination of serum and urinary neopterin levels was performed daily in 30 patients undergoing kidney transplantation for treatment of end-stage renal failure. Neopterin serum levels were determined by RIA and urinary excretion by HPLC. In parallel, the same samples were tested for creatinine content. Results indicated a strong correlation between the clearance of neopterin and creatinine. This correlation was independent of the extent of functional impairment as well as of the different causes of renal insufficiency. As a consequence, a strong relationship between serum and urinary neopterin levels was only obtained when values were corrected for different renal function by dividing them by the creatinine levels. It thus appears that major attention has to be paid to the functional state of the kidney when studying neopterin serum and/or urine values. It also appears that under these prerequisites both methods of detection as well as both sample sources yield comparable results.

Adult↗
PubMed1989

[Monitoring of renal grafts. Value of the determination of serum neopterin and neopterin versus creatinine ratio].

In a longitudinal study, 53 renal allograft recipients were investigated for changes in serum creatinine and neopterin levels and in the neopterin/creatinine (N/C) ratio which makes it possible to disregard the glomerular filtration level. The patients were divided into 5 groups according to their clinical situation: stability, acute renal failure due to acute tubular necrosis, acute graft rejection, bacterial or viral infection and cyclosporin overdosage. Only N/C discriminated between these situations, being normal (less than 200.10(-6) in groups 1 and 2, significantly elevated in groups 3 and 4 and low in group 5. The highest N/C value was observed in patients with primary cytomegalovirus infection. It is concluded that the N/C ratio is a good biochemical parameter to be used in the follow-up of renal allograft recipients.

Adult↗
PubMed1992

Neopterin as parameter of cell-mediated immunity response in thermally injured patients.

Serum neopterin levels have been determined retrospectively in 22 patients with burn injuries. Neopterin, which is produced by monocytes/macrophages following stimulation by interferons, is regarded as a marker for the activation of the cellular immune response. In most patients neopterin levels were initially in the normal range. All patients had their first operation and skin transplantation during the first week; mean neopterin levels increased significantly thereafter. Further skin transplantations or infections did not significantly influence the elevated neopterin level. This result may be due to continuous stimulation of the cellular immune system, as indicated by the elevated neopterin levels during most of the follow-up. In four low risk patients, neopterin levels always remained in the normal range. Two patients with inhalation trauma showed highly elevated neopterin levels (30-70 nmol/l) already upon admission and for 3 days thereafter. No correlation of neopterin levels with the burned body surface area was observed. However, mean serum neopterin levels were higher in the group of non-survivors (five patients) compared to survivors during the first 2 weeks after the trauma; rising neopterin levels were observed during the last 5 days before death. Although elevated neopterin levels could not be attributed either to the burn itself or to later events, the cellular immune system of burned patients was shown to be highly activated.

Adult↗
PubMed1985

The value of urinary neopterin as an immunological parameter in patients with malignant tumors of the genitourinary tract.

In 153 patients with verified neoplasias of the genitourinary tract, urinary neopterin excretion was monitored under different conditions. As control, urinary neopterin values were taken from 208 male and 209 female volunteers. Neopterin excretion was measured by high performance liquid chromatography. Patients with early tumor stages, both with bladder tumor and carcinoma of the prostate, presented almost normal urinary neopterin levels. The difference of urinary neopterin excretion between low and high stages in bladder tumor (T0-1 versus T2-4) as well in carcinoma of the prostate (stage A-B versus stage C-D) is highly significant (p less than 0.001). In the group of patients with renal cell carcinoma we could not find any correlation between tumor stage and neopterin excretion. The basal urinary neopterin values in patients with testicle tumors were as follows: 1 of 6 patients stage-I seminomatous tumors and 2 of 4 patients with stage-I non-seminomatous tumors demonstrated elevated neopterin levels. In the higher stages all patients, in both groups, exhibited pathologically increased neopterin excretion. During therapy and follow-up: all 24 stage-I (seminomatous and non-seminomatous tumors) patients showed normal neopterin levels: 1 of 3 stage-II (non-seminomatous tumors) patients and all 5 stage-IV (seminomatous and non-seminomatous tumors) patients had elevated urinary neopterin excretion. Our experience suggests that neopterin measurements may supplement laboratory examinations in patients with malignant tumor diseases of the genitourinary tract, providing meaningful information in regard to early detection of tumor progression, tumor recurrence and follow-up.

Adolescent↗
PubMed1988

Selective induction of mononuclear phagocytes to produce neopterin by interferons.

Interferon-gamma (IFN-gamma) has been shown to be a potent inducer of neopterin secretion by human peripheral blood monocytes/macrophages (1). In this paper, it is shown that other known stimuli of monocytes (e.g., to secrete proteases or to migrate) such as zymosan-activated human serum, lipopolysaccharide, human C3/iC3 and zymosan coated with complement were unable to trigger monocytes/macrophages to release neopterin. Monocytes/macrophages could be stimulated solely by IFN-gamma (25 U/ml) and IFN-alpha at very high concentrations (10,000 U/ml). In the case of human peripheral blood mononuclear cells (PBMNC), basically the same pattern was observed. If however, in the buffer controls PBMNC showed some neopterin release, all stimuli triggered an increase of neopterin secretion: 10,000 U/ml IFN-alpha induced the same amount of secreted neopterin as did 25 U/ml of IFN-gamma. Both caused higher levels of neopterin secretion than ZAS, LPS and C3/iC3. Amongst the supernatants from PBMNC, only those which were obtained from cells activated with IFN-gamma or -alpha stimulated monocytes/macrophages to produce neopterin. Supernatants from lymphocytes activated with zymosan, lipopolysaccharide and interferon did not contain neopterin, nor did the latter induce monocytes/macrophages to generate and secrete neopterin. Antibodies against IFN-gamma inhibited the triggering effect of the supernatants except when generated by IFN-alpha at 10,000 U/ml. These results demonstrate that both interferons, IFN-gamma and IFN-alpha, the latter only at a 400-fold higher concentration, can trigger monocytes/macrophages directly to secrete neopterin. ZAS, LPS and C3/iC3 are weakly effective only on a mixture of lymphocytes and monocytes/macrophages, provided this cell mixture shows already a basic spontaneous neopterin release.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Posttransplant neopterin excretion in renal allograft recipients--a reliable diagnostic aid for acute rejection and a predictive marker of long-term graft survival.

During the immediate posttransplant period, daily measurements of urinary neopterin, which is produced by stimulated macrophages, were evaluated in 294 consecutive recipients of renal allografts for their diagnostic value in acute graft rejection. The ability of mean and peak neopterin excretion values to predict long-term graft survival was analyzed on the basis of an eight-year follow-up. Immunosuppressive therapy (cyclosporine +/- prednisone versus azathioprine + prednisone) and initial nonfunction did not influence neopterin excretion. In patients with rejection episodes and in those with infections, neopterin levels were significantly increased. Diagnostic sensitivity and specificity with regard to rejection diagnosis were assessed for different levels of neopterin. By statistical analysis, a significant association between increased neopterin and higher risk of rejection was found, which was particularly pronounced in patients receiving cyclosporine. Increase in neopterin excretion preceded clinical rejection diagnosis by up to four days. Peak neopterin values above 800 mumols/mol urinary creatinine observed during the posttransplant period, were associated with significantly poorer graft survival. A multivariate analysis showed that peak neopterin levels, age of patients, and early posttransplant presence/absence of acute rejection were significant and independent joint predictors for long-term graft survival. Measurement of neopterin can be of help as an additional marker in early diagnosis of renal allograft rejection, and high neopterin values during the initial posttransplant period are associated with poorer long-term graft survival.

Adolescent↗
PubMed1992

Urinary and pancreatic juice neopterin excretion after combined pancreas-kidney transplantation.

The aim of this study was to investigate excretion of urinary and pancreatic juice neopterin in patients after combined pancreas-kidney transplantation and to relate it to the clinical course. The study design was a prospective observation study. Thirty consecutive patients with end-stage diabetic disease received a simultaneous pancreas-kidney transplant with pancreaticocystostomy and temporary exteriorization of pancreatic juice. In 30 patients urinary neopterin (UN) was measured daily from day +1 until hospital discharge by high-performance liquid chromatography; in ten of these 30 patients pancreatic juice neopterin (PJN) was additionally analyzed daily from day +1 for as long as pancreatic juice was diverted to the exterior. Elevated urinary neopterin levels were observed in acute cellular rejection (19/24 rejection episodes) and in bacterial infection (9/16 cases)--however, increments were more pronounced in acute cellular rejection. In contrast, pancreatic juice neopterin increased in all seven observed pancreatic graft rejection episodes. Pancreatic juice infection did not result in a rise in pancreatic juice neopterin excretion. Patients without postoperative complications exhibited stable and low urinary/pancreatic juice neopterin levels. The highest urinary neopterin levels were observed in CMV disease. Levels measured prior to discharge from hospital did not correlate with graft and patient survival. Evaluation of urinary and pancreatic juice neopterin, although nonspecific, helps identify patients with an uncomplicated or complicated clinical course. Pancreatic juice neopterin appears to be superior to urinary neopterin in early detection of pancreatic graft rejection. This may be of particular importance in monitoring nonuremic pancreas allograft recipients.

Adult↗
PubMed1991

Elevated serum neopterin levels in atherosclerosis.

Plasma levels of neopterin were determined in patients with different clinical stages of atherosclerosis. Non-hospitalized patients with atherosclerosis had serum and plasma neopterin levels within the normal range of the assay (6 +/- 2 nM). These values were not significantly different from those reported for healthy blood donors (5 +/- 2 nM). In contrast, about 50% (29 out of 61) of hospitalized patients undergoing conservative or surgical therapy had neopterin plasma levels, which exceeded the normal range (greater than 10 nM) up to 10-fold. The two groups differ on a significance level of P less than 0.01. For further evaluation hospitalized patients were subgrouped according to neopterin levels. In the subgroup with elevated neopterin levels patients with higher Frederickson types of atherosclerosis were overrepresented compared to patients with normal neopterin levels. Type 4 differed significantly from patients without pathological changes of lipoprotein (P less than 0.05). Only 3 patients suffered from minimal skin necrosis, two of them had elevated neopterin levels. Significantly more patients with peripheral artery occlusions had elevated neopterin levels than patients with occlusions of central arteries (P less than 0.05). All other criteria used for comparison (sex, age, smoking, antioxidant status, diabetes, hypertension, adipositas, hyperuricemia) did not vary significantly in both subgroups. These data indicate that neopterin plasma levels might be a valuable parameter in activity staging and therapeutic follow up of atherosclerotic patients. Additionally, an involvement of the nonspecific immune system in atherogenesis is suggested by the increased plasma neopterin concentrations.

Aged↗
PubMed1986

Assessment of plasma neopterin in clinical kidney transplantation.

Serial plasma samples of 172 kidney transplant recipients and 42 chronic dialysis patients were evaluated retrospectively in a radioimmunoassay to determine the clinical relevance of plasma neopterin levels. Dialysis patients had a higher neopterin level 196 +/- 82 nmol/L (mean +/- SD) than 70 healthy controls (7 +/- 4 nmol/L). In 45 patients with a completely uneventful postoperative course, elevated pretransplant neopterin levels dropped rapidly within a week to a mean of 30 nmol/L and remained stable thereafter. In 22 outpatients with stable graft function there was a highly significant correlation between 170 paired serum creatinine and plasma neopterin values (r = 0.94). A group of 13 patients had experienced delayed graft function (ATN) without rejection. Their one-week mean neopterin level was 100 nmol/L and continued to drop in parallel with the serum creatinine. Another 15 patients rejected their kidneys irreversibly within 3 weeks-6 of them had extremely high neopterin levels during the rejection process (range 500-1000 nmol/L) that were not seen in other patients. A total of 169 rejection episodes in 43 patients were treated with bolus-dose cortisone. On the day of bolus therapy, both serum creatinine (P less than 0.002) and neopterin (P less than 0.005) were elevated. At 24 hours prior to bolus cortisone therapy, creatinine levels were not significantly elevated, whereas there was a significant rise in plasma neopterin (P less than 0.01). The overall sensitivity of neopterin increase was 86% with a 17% probability of false positives, and the sensitivity was 95% in biopsy-proved rejections. Plasma neopterin appears to be a useful marker for early detection of rejection and for identifying severe rejections that are not responsive to treatment.

Biopterins↗
PubMed1992

The role of neopterin as a monitor of cellular immune activation in transplantation, inflammatory, infectious, and malignant diseases.

The accumulated knowledge about the organization and function of the human immune system contributes to a better understanding of the pathogenesis of most diverse disorders and is opening new avenues for therapeutic regimens. To gain further insight into the complex interactions within the components of the immune system, it has become increasingly necessary to develop rapid and simple methods to monitor the status of the immune system in patients. The determination of neopterin concentrations in human body fluids allows to investigate sensitively the cell-mediated immune status to be investigated with considerable sensitivity. In recent years it was shown that production and release of neopterin is inducible in human monocytes/macrophages by interferon gamma. Increased neopterin levels indicate endogenous formation of gamma interferon, and monitoring of neopterin levels therefore permits the activation status of the cell-mediated immune system to be examined. Neopterin concentrations in serum and in urine increase in parallel to the clinical course of infections with viruses, intracellular bacteria, and parasites. In patients with human immunodeficiency virus infection neopterin concentration in serum and urine is a significant predictor of disease progression, the statistical power being similar to CD4+ T-cell numbers. In patients with autoimmune disorders, neopterin levels correlate with the extent and the activity of the disease. Neopterin concentrations are also sensitive indicators of immunological complications in allograft recipients. In certain malignant diseases neopterin concentrations correlate with the stage of the disease and bear prognostic information. Results of neopterin measurements agree with the important role that the cellular immune system plays in these disorders.

Animals↗
PubMed1992

Monitoring of serum neopterin in renal transplant recipients.

Postoperative management of kidney allograft recipients requires a reliable and rapid diagnostic method so that proper therapy can be initiated. In this study, we tried to correlate serum neopterin levels with different conditions after transplantation. Serial serum neopterin levels were assessed after operation. Serum neopterin levels of uremic patients were significantly higher than those of healthy persons (239.9 +/- 177.7 nmole/L, n = 33 vs 6.14 +/- 2.78 nmole/L, n = 10, p < 0.001). In recipients with a stable post-transplant course, the serum neopterin level was low. On the contrary, acute rejection episodes were associated with a high level of serum neopterin which declined after successful treatment, although the difference was not significant (96.2 +/- 57.7 nmole/L vs 56 +/- 38.1 nmole/L, p > 0.05). The serum neopterin level was also high in post-transplant acute tubular necrosis (ATN, 256.6 nmole/L), which gradually declined parallel to the resolution of ATN. The neopterin level was low in patients with cyclosporine nephrotoxicity (17.8 +/- 7.6 nmole/L). In summary, the serum neopterin levels were persistently high in uremic and post-transplant ATN patients. Acute rejection episodes were correlated with an increased level of neopterin. It appears that daily measurement of the serum neopterin level may be useful for biochemical detection of immunologic complications in allograft recipients.

Adult↗
PubMed1991

Clinical significance of serum and urinary neopterins in patients with chronic renal disease.

To determine the clinical significance of serum and urinary neopterins in patients with chronic renal disease, we measured these values using IMMUtest Neopterin RIA kits. Serum neopterin levels in patients with chronic glomerulonephritis (CGN) (10.2 +/- 8.1 nmol/l) and in those with chronic renal failure (CRF) (109 +/- 90) were significantly increased compared with the control subjects (C) (4.2 +/- 2.4) (p less than 0.001). The levels of serum neopterins in patients on chronic hemodialysis (HD) (212 +/- 106) were increased almost twofold compared with CRF (p less than 0.001). In CGN and CRF, a strong positive correlation was demonstrated between serum neopterin levels and serum creatinine concentrations (r = 0.95, p less than 0.001). In HD patients, neopterin levels and serum were not correlated with the length of time on dialysis. The urinary neopterin excretion ratios (urinary neopterin/urinary creatinine level) in CRF (227 +/- 114 mumols/molCr) were significantly increased compared with C (116 +/- 43) (p less than 0.01). A significantly negative correlation was observed between the urinary neopterin levels and the creatinine clearance in CGN and CRF (p less than 0.01). These data suggest that, in patients with chronic renal disease, the neopterin levels in serum are closely linked with glomerular filtration rate and yet the urinary neopterin/creatinine ratios may reflect the predominance of increased tubular secretion of neopterin over the renal injury per se.

Adult↗