Mean C2 Research Articles

C2 –C0 VALUES DETERMINATION FOR MONITORING CYCLOSPORINE THERAPHY IN STABLE HEART TRANSPLANTED PATIENTS

O340 Aims: The cyclosporine two hours plasmatic level determination (C2) seems to be better related to safety and efficacy of immunosuppressive regimen than throught level (C0) in stable and “the novo” liver and kidney transplanted patients. There are not clear results about the safe and efficacy of C2 level compared to C0 in the immunosuppressive regimen of stable transplanted heart; this study have been performed in stable transplanted heart to determine efficacy and safety of C2 versus C0. Methods: From 01/09/01 to 15/03/04, 1148 samples (574 C0 determination and related C2) were taken to 110 stable and “the novo” heart transplanted patients, orally treated with Neoral micro-emulsioned Cyclosporine (Cya) and monitored with C0 trought levels. From this population, 60 patients with a sufficient number of samples/patient (at least 4) with a mean ratio of 5,2, were studied and divided in two subgroups: Group A, 22 patients with a relatively constant C2 and related AUC values (“costant” defines as +/- 30% in four different samples) and: Group B, 38 patients “inconstant adsorbers”, with great variation (> +/- 30%) of C2 values despite constant given cyclosporine dosage. Cya side effects, acute rejection episodes and chronic graft rejection were observed and related to C2 measured levels. Results: Total number of biopsies was 427; 21 episodes of acute rejection ISHLT grade > IIIA occurred (21/427, 4,9%). There was no statistical difference between number of acute rejection in the two groups. Only 7 rejection episodes occurred in transplanted patients over 1 year; in the others events, there was no difference about immunosuppressive treatment (triple standard : Cya+prednisone+ azathioprine). In the patients free of rejection, mean C2 level observed were: 1500 ng/ml (range 1180-1890) at three months from transplantation, 1200 ng/ml (range 1050-1630) at 6th month, 1000 ng/ml (range 650-1440) at 1 year, 750 ng/ml (range 550-970) at two years. Higher C2 levels were related to increased frequency of Cya side effects: sistemic hypertension (47% group A vs 36% group B), gum hyperplasia (A 21% vs B 9%), hypercolesterolaemia (A 42% vs B 22%), tremors and peripheral paraestesia (A 47% vs B 31%). There were no differences between the two group regard renal disfunction. Conclusions: Despite the small number of patients C2 levels determination appears to be very helpfull when associated to C0 in clinical monitoring of immunosuppression (identification of Cya over-exposed and low-adsorber patient). In heart transplanted patients the recommendable C2 levels appeares to be higher in respect to liver or kidney transplanted patients. Because of an higher dosage of Cya, C2 monitoring alone can be associated to an higher report of side effects than in liver and kidney transplantation.

Experience with cyclosporine

The concentration at 2 hours after drug intake (C2) is proposed to optimise clinical outcomes in organ transplantation and for adjustment of the regimen of cyclosporine. A population based pharmacokinetic study was undertaken during the first 30 days post-liver transplantation. Preliminary results observed during this study on C0 and C2 values are described here. Thirty-seven patients with first hepatic transplantation were included in a single center, prospective study conducted under conditions of normal practice. Dose adjustments were made according to C0. Cyclosporine C0 and C2 were assayed by an immunoassay (EMIT) and by a HPLC technique. Clinical outcome was assessed by occurrence and severity of acute rejection. Our data shows that average blood C0 and C2 concentrations are significantly different with the two techniques. From the third day to the end of the study, mean C2 (EMIT) were within or near the recommended values. This was associated with a low rejection rate (8.8%). Nevertheless, individual values are largely dispersed and low cyclosporine absorption profiles are identified. Mean cyclosporine dose was low compared to a previous study (7.65 ± 4.28 mg/kg/day). Our data suggest that the target ranges need to be adjusted when different techniques are applied and that optimal cyclosporine regimen to achieve the C2 goal and low rejection rate remains to be defined. Pharmacokinetic models based on population study are needed to describe normal and abnormal cyclosporine absorption profiles with higher accuracy.

The value of C2 monitoring in stable renal allograft recipients on maintenance immunosuppression.

Cyclosporin A (CyA) is a drug with a narrow therapeutic window and highly variable pharmacokinetics. Therapeutic drug monitoring is essential and conventionally has been guided by trough levels (C0). Recent evidence indicates that a single blood concentration measurement 2 h after CyA administration (C2) is a more accurate predictor of drug exposure and clinical events than determination of C0. To date, limited prospective data are available with respect to risks and benefits of C2 monitoring in renal transplant recipients, and little experience exists with C2 monitoring in maintenance patients. In 127 long-term renal allograft recipients, we determined C2 levels in addition to conventional C0 and observed clinical outcome over a period of 13.6 +/- 3.1 months. To determine the precision of monitoring, we repeatedly determined C0 and C2 levels in 46 stable patients without dose change. Clinical outcome was excellent (patient survival 100%, graft survival 97%), with only two borderline rejections, although C2 levels (564 +/- 186 ng/ml) were lower than recommended so far for maintenance patients. We found no significant differences in C2 levels between patients with rejection and CyA toxicity. Receiver operating characteristic (ROC) analysis showed no prediction for risk of rejection, toxicity or infection by C2 levels. Repeated determinations of both C0 and C2 levels in 46 patients revealed a high intra-patient variability. In these patients, the coefficient of variation for C2 was only marginally better compared with C0. We conclude that in maintenance patients, C2 concentrations between 500 and 600 ng/ml are well tolerated and provide effective and safe rejection prophylaxis. Although mean C2 levels do not seem to be helpful in identifying patients at risk for rejection, they may be useful to detect over-immunosuppression and to improve long-term allograft survival further by reducing CyA nephrotoxicity.

Relationship between alignment of upper and lower cervical spine in asymptomatic individuals.

The aim of this study was to establish standard values for the normal alignment of the upper cervical spine and to clarify its relationship with the lower cervical spine in terms of alignment Three hundred thirteen asymptomatic volunteers (155 men and 158 women) participated in this study. Lateral radiographs were obtained with the neck in neutral position, and the angles formed by the occiput (Oc) and the axis, the atlas and the axis, and C-2 to C-7 were measured. The mean Oc-C2 angle was 14.5 +/- 8 degrees in men and 16 +/- 8.5 degrees in women; the mean C1-2 angle was 26.5 +/- 7 degrees and 28.9 +/- 6.7 degrees, respectively; and the mean C2-7 angle was 16.2 +/- 12.9 degrees and 10.5 +/- 10.3 degrees, respectively. Although weak, statistically significant negative correlation was observed between Oc-C2 and C2-7 angles (r = -0.31 in men and -0.37 in women), and between C1-2 and C2-7 angles (r = -0.22 in men and -0.22 in women). The correlation coefficient between the Oc-C2 and C2-7 angles was greater than that between the C1-2 and C2-7angles. Such relationships between alignment of the upper and lower cervical spines should be taken into consideration when performing occipitocervical fusion.

C2 Targets and multivariate predictors of C2 levels in stable heart transplant patients immunosuppressed on a C0-based regimen

Neoral dose monitoring in heart transplantation (HT) is based on trough levels (C0), since cyclosporine A (CsA) 2-hr peak (C2) targets have not been established. To identify C2 targets and clinical correlates of C0 and C2, we studied 314 stable HT pts (251 male, aged 50±14 yrs at HT, follow-up 6.8±4 yrs, range 1 mo-15 yrs), on a C0-based regimen. Mean C0 and C2 levels (ng/mL) were 268±80 and 1031±386 respectively for pts (n=19) in the first 3 mo; 230±49 and 955±239 in pts (n=10) between 4 and 12 mo; 157±53 and 745±235 in pts (n=285) after 1 yr. Our target C0 levels (ng/mL) are 150-400 (first 3 mo), 150-300 (4-12 mo), 100-250 (>12mo). For pts within the target C0 the corresponding C2 (ng/mL) were 600-1500 (first 3 mo), 600-1300 (4 to 12 mo), 500-1000 (>12mo). C2 correlated with C0 (Pearson, r=0.61, p=0.0001). C2 correlated better with CsA dose than C0 (r=0.50, p=0.0001 vs r=0.36, p=0.0001). Between pts CsA dose varied by a factor of 9.3; the C/dose ratio varied by a factor of 8.5 for C2 and of 15.6 for C0. Pts with higher C2 (>550) had higher rejection scores at 1 yr (p=0.04) and during whole follow-up (p=0.04) than pts with lower C2 (t-test). This did not apply to higher (>110) C0 vs. lower C0. Both C2 and C0 correlated with blood urea (r=-0.19, p=0.001; r=-0.18, p=0.002) and creatinine (r=-0.16, p=0.004; r=-0.20, p=0.0001 respectively). By logistic regression higher C2 (>550 ng/mL) was associated with higher CsA and steroid load (mg/Kg) at 1 yr (p=0.038; p=0.001 respectively), lower blood urea (p=0.003) and tended to be associated with high total severe rejection score (p=0.07). Regression analysis on higher C0 (>110 ng/mL) did not show associations. Thus, C2 showed better correlation with CsA dose, renal function, rejection profile and less variability between pts than C0. C2 may improve CsA-based immunosuppression in HT.

Large and small artery compliance changes during hemodialysis

Background: Cardiovascular disease is the major cause of mortality and morbidity in patients undergoing hemodialysis. Reduced arterial compliance is an independent predictor of cardiovascular mortality in end stage renal disease and can be measured noninvasively using pulse wave analysis technology. Methods: Ten chronic hemodialysis patients were evaluated using pulse wave analysis to determine large and small vessel compliance before hemodialysis, midway through the treatment, and at the end of the treatment. Serum calcium was measured before and after hemodialysis. Results: No significant changes in systolic blood pressure (BP), diastolic BP, pulse pressure, or heart rate occurred during hemodialysis. A significant decrease in small vessel compliance (C2) occurred during the treatment, with the mean C2 decreasing from 5.6 ± 2.7 mL/mm Hg × 10 predialysis to 3.3 ± 1.5 mL/mm Hg × 10 midway through the treatment ( P = .04) and to 3.9 ± 4.3 mL/mm Hg × 10 at the end of the dialysis treatment. There was no significant change in large vessel compliance (C1). Serum calcium increased significantly during the dialysis treatment from 8.0 ± 1.2 mg/dL to 9.8 ± 0.9 mg/dL ( P = .003). Conclusions: Significant decreases in small artery compliance occur without systolic or diastolic BP changes during routine hemodialysis. A significant increase in serum calcium also occurred during hemodialysis. Measurements of arterial compliance during hemodialysis may be an important tool to identify patients with vascular responses, which may place them at greater risk for cardiovascular disease.

Heterogeneity of DNA distribution in diploid cells: a new predictive discriminant factor for solid tumour behaviour.

Spatial nuclear DNA heterogeneity distribution of Feulgen‐stained DNA diploid cells was studied by image cytometry in voided urine of 119 patients without bladder tumour (n=20) and with initial (n=23) or previous (n=76) diagnosed bladder tumour. For each patient, repetitive DNA measurements were performed during 1–4 years of follow up. Only cells of diploid DNA histograms and diploid subpopulations of aneuploid DNA histograms were used for analysis. DNA heterogeneity distribution of these diploid cells was quantified by statistical parameters of each nuclear optical density distribution. Discriminant analysis was performed on three groups of DNA histograms. Group A (n=44): aneuploid DNA histograms of patients with bladder tumour. Group D (n=55): 38 diploid DNA histograms of the 20 patients without bladder tumour (subgroup D1) and 17 diploid DNA histograms of patients with a non‐recurrent bladder tumour (subgroup D2). Group R (n=27): diploid DNA histograms of patients with bladder tumour recurrence. No statistically significant discriminant function was found to separate D1 and D2. However, the first canonical discriminant function C1 differentiated diploid cells of diploid DNA histograms (group D and group R) from diploid cell subpopulations of aneuploid DNA histograms (group A). Mean C1 values were 1.06, 0.84 and –1.45 for groups R, D and A, respectively. The second canonical discriminant function C2 differentiated diploid DNA histograms of patients with bladder tumour recurrence (group R) from diploid DNA histograms of patients without bladder tumour or without bladder tumour recurrence (group D). Mean C2 values were 1.78 and –0.76 for groups R and D, respectively. In 95% confidence limit, the rate of rediscrimination using the two first canonical discriminant functions C1 and C2 were 86.4, 74.5 and 74.1% for groups A, D and R, respectively. Percent of “grouped” cases correctly classified was 78.6%. Thus spatial DNA heterogeneity distribution of diploid cells seems to quantitate probable genetic instability as a function of clinical evolution such as tumour recurrence, and suggests the possible presence of aneuploid stemlines in a heterogeneous tumour, even if a diploid DNA histogram is observed in a single sample. From standardized C1 and C2 canonical discriminant function coefficients, a DNA heterogeneity index (2c‐HI) is proposed to characterize diploid cells providing a descriptive and predictive discriminant factor for solid tumour behaviour.

Conduta obstétrica no óbito fetal

Although 80 to 90% of all dead fetuses may be spontaneously eliminated after two to three weeks from death, labor induction has been the mostly used management. The purpose of the current study was to evaluate the results of labor induction for pregnancies with fetal death and gestation age above 20 weeks. It was a descriptive clinical study which was performed at the Hospital e Maternidade Leonor Mendes de Barros in Sao Paulo, Brazil. One hundred and twenty-two pregnancies with fetal death were evaluated regarding their social and demographic characteristics, causes of fetal death, previous pregnancies history and delivery (induction, route, complications). The statistical procedures used were estimation of mean and standard deviation and c2. The main causes of fetal death were hypertension and infections. The mostly used drug for labor induction was misoprostol (37.7%) followed by oxytocin (19.7%), while 27% of cases had spontaneous onset of labor. The mean time of induction was 3 hours. The majority of women had vaginal delivery and cesarean section was performed in 9.1% of them. It is concluded that labor induction for fetal death is safe and efficient, irrespective of the method used. Misoprostol when used in the vagina is specially useful for cases with an unripe cervix because of the modifying effect of the drug on the cervix.

Radioassays for quantitation of intact complement proteins C2 and B in human serum

Availability of polyclonal and monoclonal antibodies recognizing determinants on the major cleavage fragments of complement proteins C2 and B enabled development of sensitive radioassays which can be used to quantitate the intact proteins in human sera. Changes in C2 and B concentrations indicative of classical or alternative pathway activation, or both, were seen in normal serum after incubation with complement activators. We determined the normal range ( x ± 2 SD ) of C2 concentration to be 11–35 μg/ml in 32 healthy individuals, and that of protein B to be 74–286 μg/ml. Sera from patients with systemic lupus erythematosus (SLE), septic shock, infections, and following orthopedic surgery were then assayed. Mean protein B concentration was significantly higher in SLE sera ( P = 0.002) and in the infected and post-operative (acute-phase) sera ( P < 0.001), and the mean C2 concentration in the septic shock group ( P < 0.001) was significantly lower than the mean of healthy individuals. Intact C2 was not detected in known C2-dependent individuals. These assays allow parallel quantitation of the structurally and functionally homologous proteins of the classical (C2) and alternative (B) pathways, which is of interest in patients with genetic and acquired hypocomplementemia.

4 direct measurement of CEA in serum by one step enzyme immunoassay

Immunosuppression has been one of the great challenges in pediatric recipients of kidney allografts. Cyclosporine (CsA) has evolved during the past 25 years of transplantation. It requires frequent blood level monitoring because of its narrow therapeutic window and interpatient and intrapatient variability. Neoral (Novartis) is no exception. Ideally, monitoring of blood levels should also include determination of the area under the time-concentration curve (AUC) to better target the therapeutic window, thus avoiding underdosing or overdosing, especially in pediatric patients. A single blood concentration measurement 2 hours after Neoral administration (C2) has been shown to be a more for accurate predictor of drug exposure than trough levels (C0). Therefore, its use may lead to reduction in the incidence and severity of cellular rejection and of CsA toxicity. Some studies have shown that the metabolites/CsA ratio is substantially lower using C2 than C0, however, the between-assay differences for C2 monitoring have not been considered.The purpose of this study was to evaluate CsA C0 and C2 levels, determined using monoclonal fluorescence polarization immunoassay (FPIA)/TDx and enzyme multiplied immunoassay (EMIT). CsA levels were determined using a radioimmunoassay (RIA) in 30 pediatric transplant recipients with stable renal function within 42.7 mean months follow-up. Mean age was 13.4 years; 15 children were girls; 23 patients were recipients of cadaveric kidneys. The mean CsA microemulsion dose was 5.7 mg/kg/d. The 3 methods showed a high correlation between C0 and C2 (r ≥ 0.97). A linear regression slope was significantly higher for C0 than C2 (P < .001). The CsA concentrations both at C0 and C2 were significantly higher with FPIA than with RIA (P < .009) but no differences were found for EMITT (P = .2). The mean C0 level for FPIA was 22% and 26% higher than RIA and EMIT, respectively. The mean C2, for FPIA was 7% and 12% higher than RIA and EMIT, respectively. In conclusion, CsA levels determined using RIA or EMIT are better than using FPIA/Tx; also, C2 CsA levels are more accurate than C0 in pediatric transplantation patients.

1 Saliva levels of 17-OH progesterone during the menstrual cycle in women

Immunosuppression has been one of the great challenges in pediatric recipients of kidney allografts. Cyclosporine (CsA) has evolved during the past 25 years of transplantation. It requires frequent blood level monitoring because of its narrow therapeutic window and interpatient and intrapatient variability. Neoral (Novartis) is no exception. Ideally, monitoring of blood levels should also include determination of the area under the time-concentration curve (AUC) to better target the therapeutic window, thus avoiding underdosing or overdosing, especially in pediatric patients. A single blood concentration measurement 2 hours after Neoral administration (C2) has been shown to be a more for accurate predictor of drug exposure than trough levels (C0). Therefore, its use may lead to reduction in the incidence and severity of cellular rejection and of CsA toxicity. Some studies have shown that the metabolites/CsA ratio is substantially lower using C2 than C0, however, the between-assay differences for C2 monitoring have not been considered.The purpose of this study was to evaluate CsA C0 and C2 levels, determined using monoclonal fluorescence polarization immunoassay (FPIA)/TDx and enzyme multiplied immunoassay (EMIT). CsA levels were determined using a radioimmunoassay (RIA) in 30 pediatric transplant recipients with stable renal function within 42.7 mean months follow-up. Mean age was 13.4 years; 15 children were girls; 23 patients were recipients of cadaveric kidneys. The mean CsA microemulsion dose was 5.7 mg/kg/d. The 3 methods showed a high correlation between C0 and C2 (r ≥ 0.97). A linear regression slope was significantly higher for C0 than C2 (P < .001). The CsA concentrations both at C0 and C2 were significantly higher with FPIA than with RIA (P < .009) but no differences were found for EMITT (P = .2). The mean C0 level for FPIA was 22% and 26% higher than RIA and EMIT, respectively. The mean C2, for FPIA was 7% and 12% higher than RIA and EMIT, respectively. In conclusion, CsA levels determined using RIA or EMIT are better than using FPIA/Tx; also, C2 CsA levels are more accurate than C0 in pediatric transplantation patients.

Depletion of C2 and C4 in sera from hamsters bearing herpes simplex type 2-induced tumors.

Total hemolytic complement activity (CH50) was compared in sera from normal and tumor-bearing hamsters. CH50 ranged from 160-216 in normal animals and from 82 to 152 in tumor-bearing animals. Preliminary screening assays indicated that of 9 complement components assayed, only C2 and C4 showed differences in titer in both normal and tumor-bearer sera. In an expanded study, examination of sera from 12 normal and 14 tumor-bearing hamsters showed that the mean C4 and C2 levels were approximately 88 and 70% below those seen in normal sera, respectively.