Patients with obesity have more inflamed joints and higher CRP levels during the disease course in ACPA-positive RA but not in ACPA-negative RA.

BACKGROUND: Obese RA patients have higher disease activity scores (DAS). Previous research showed that obese RA patients have higher tender joint count (TJC) and VAS general health. However, it remains unclear whether DAS components measuring local and systemic inflammation (swollen joint count (SJC), CRP) are increased and if this is present in the total RA population or confined to an ACPA subgroup. As ACPA is suggested to enhance inflammatory responses, we hypothesized that the association of obesity with SJC and CRP is present especially in ACPA-positive RA. We therefore studied associations of obesity with courses of DAS components in ACPA subgroups. METHODS: We studied 649 RA patients (291 ACPA-positive), included in the Leiden Early Arthritis Clinic. Five-year courses of DAS44 and DAS44 components (SJC-44, TJC-53, CRP, VAS (0-100)) were compared between RA patients with normal weight (BMI 18.5-24.9), overweight (25.0-29.9), and obesity (≥ 30.0), stratified for ACPA. Linear/Poisson mixed models with a knot at 4 months were used. RESULTS: Obese RA patients had + 0.32 higher DAS compared to normal weight during the 5-year follow-up. In ACPA-positive RA, obese patients had + 0.43 (95% CI: 0.22, 0.64) higher DAS, whereas in ACPA-negative RA, this difference was smaller and not statistically significant: + 0.19 (95% CI: - 0.01, 0.38). In ACPA-positive RA, all DAS components were significantly higher in obese patients compared to normal weight: SJC + 60% (IRR1.60; 95% CI: 1.18, 2.16), CRP + 3.7 mg/L (95% CI:0.95, 6.53), TJC + 55% (IRR1.55; 95% CI:1.15, 2.10), and VAS + 9 (95% CI: 4.0, 14.2). ACPA-negative obese RA patients tended to have higher TJC (IRR1.22; 95% CI: 0.96, 1.55) and VAS (ß4.3; 95% CI: - 0.4, 9.0), while SJC (IRR1.07; 95% CI:0.85, 1.33) and CRP (ß0.24; 95% CI: - 1.29, 3.32) were unaffected. CONCLUSION: The association of obesity with a worse DAS course is mainly present in ACPA-positive RA; especially SJC and CRP levels remain higher in ACPA-positive RA patients with obesity but not ACPA-negative RA patients. This is the first demonstration that obesity influences the disease course of ACPA-positive and ACPA-negative RA differently.

Disentangling heterogeneity in contemporary undifferentiated arthritis - A large cohort study using latent class analysis.

OBJECTIVES: Undifferentiated arthritis(UA) is clinically heterogeneous and differs in outcomes ranging from spontaneous resolution to RA-development. Therefore, we hypothesized that subgroups exist within UA and we aimed to identify homogeneous groups based on clinical features, and thereafter to relate these groups to the outcomes spontaneous resolution and RA-development. These outcomes can only be studied in UA-patients in which DMARD-treatment does not influence the natural disease course; these cohorts are scarce. METHODS: We studied autoantibody-negative UA-patients (not fulfilling 1987/2010 RA-criteria, no alternate diagnosis), included in the Leiden Early Arthritis Clinic between 1993 and 2006, when early DMARD-treatment in UA was infrequent. Latent class analysis was used to identify subgroups based on combinations of clinical features. Within these subgroups, test-characteristics were assessed for spontaneous resolution of arthritis and RA-development within 1 year. RESULTS: 310 consecutive UA-patients were studied. Five classes were identified: location and number of swollen joints were most distinguishing. Classes were characterized by: 1) polyarthritis, often symmetric; 2) oligoarthritis, frequently with subacute onset; 3) wrist-monoarthritis, often with subacute onset, increased BMI and without morning stiffness; 4) small-joint monoarthritis, often without increased acute phase reactants, and 5) large-joint monoarthritis, often with subacute onset. Studying the classes in relation to the outcomes revealed that patients without spontaneous resolution (thus having persistent disease) were nearly absent in the classes characterized by monoarthritis (specificity >90%). Additionally, patients who developed RA were infrequent in monoarthritis classes (sensitivity <7%). CONCLUSION: Using a data-driven unsupervised approach, five subgroups within contemporary UA were identified. These have differences in the natural course of disease.

Single nucleotide polymorphism in IL1B is associated with infection risk in paediatric acute myeloid leukaemia.

We evaluated single nucleotide polymorphisms (SNPs) associated with infection risk in children with newly diagnosed acute myeloid leukaemia (AML). We conducted a multicentre, prospective cohort study that included children aged ≤18 years with de novo AML. DNA was isolated from blood lymphocytes or buccal swabs, and candidate gene SNP analysis was conducted. Primary outcome was the occurrence of microbiologically documented sterile site infection during chemotherapy. Secondary outcomes were Gram-positive and -negative infections, viridans group streptococcal infection and proven/probable invasive fungal infection. Interpretation was guided by consistency in risk alleles and microbiologic agent with previous literature. Over the study period 254 children and adolescents with AML were enrolled. Overall, 190 (74.8%) had at least one sterile site microbiologically documented infection. Among the 172 with inferred European ancestry and DNA available, nine significant associations were observed; two were consistent with previous literature. Allele A at IL1B (rs16944) was associated with decreased microbiologically documented infection, and allele G at IL10 (rs1800896) was associated with increased risk of Gram-positive infection. We identified SNPs associated with infection risk in paediatric AML. Genotype may provide insight into mechanisms of infection risk that could be used for supportive-care novel treatments.

The CD48 receptor mediates Staphylococcus aureus human and murine eosinophil activation.

BACKGROUND: Allergy is characterized by eosinophilia and an increased susceptibility to microbial infection. Atopic dermatitis (AD) is typically associated with Staphylococcus aureus (SA) colonization. Some of the mechanisms by which SA and its exotoxins interact with eosinophils remain elusive. CD48, a glycosylphosphatidylinositol-anchored receptor belonging to the CD2 family, participates in mast cells-SA stimulating cross-talk, facilitates the formation of the mast cell/eosinophils effector unit and as expressed by eosinophils, mediates experimental asthma. OBJECTIVE: To investigate the role of CD48 expressed on human peripheral blood and mouse bone marrow-derived eosinophils (BMEos) in their interaction with heat-killed SA and its three exotoxins, Staphylococcal enterotoxin B (SEB), protein A (PtA) and peptidoglycan (PGN). METHODS: Eosinophils were obtained from human peripheral blood and BM of WT and CD48-/- mice. SA was heat killed and eosinophils-SA/exotoxins interactions were analyzed by confocal microscopy, adhesion and degranulation, cell viability, cytokine release and cell signalling. In addition, peritonitis was induced by SEB injection into CD48-/- and WT mice. CD48 expression was studied in AD patients' skin and as expressed on their leucocytes in the peripheral blood. RESULTS: We provide evidence for the recognition and direct physical interaction between eosinophils and SA/exotoxins. Skin of AD patients showed a striking increase of eosinophil-associated CD48 expression while on peripheral blood leucocytes it was down-regulated. SA/exotoxins enhanced CD48 eosinophil expression, bound to CD48 and caused eosinophil activation and signal transduction. These effects were significantly decreased by blocking CD48 on human eosinophils or in BMEos from CD48-/- mice. We have also explored the role of CD48 in a SEB-induced peritonitis model in CD48-/- mice by evaluating inflammatory peritoneal cells, eosinophil numbers and activation. CONCLUSIONS: These data demonstrate the important role of CD48 in SA/exotoxins-eosinophil activating interactions that can take place during allergic responses and indicate CD48 as a novel therapeutic target for allergy and especially of AD.

Primary tumor location and bevacizumab effectiveness in patients with metastatic colorectal cancer.

BACKGROUND: There is an unmet need for predictive markers for the antiangiogenic agent bevacizumab in metastatic colorectal cancer (mCRC). We aimed to assess whether the location of the primary tumor is associated with bevacizumab effectiveness when combined with capecitabine and oxaliplatin (CAPEOX) in the first-line treatment of patients with mCRC. PATIENTS AND METHODS: A cohort of 667 consecutive patients with mCRC from the general community treated from 2006 to 2011 with CAPEOX and bevacizumab as standard first-line therapy was compared with a cohort of 213 patients treated with CAPEOX from 2003 to 2006, before bevacizumab was approved. Main outcome measures were progression-free survival (PFS) and overall survival (OS). Differences in outcome were tested using Kaplan-Meier curves and log-rank tests, and multivariate analyses were carried out using Cox Proportional Hazards models. RESULTS: Patients treated with CAPEOX and bevacizumab with primary tumors originating in the sigmoid colon and rectum had a significantly better outcome than patients with primary tumors originating from the cecum to the descending colon, both for PFS (median PFS 9.3 versus 7.2 months; hazard ratio (HR) 0.68, 95% confidence interval (CI) 0.56-0.82) and for OS (median OS 23.5 versus 13.0 months; HR 0.47, 95% CI 0.38-0.57). This difference was confirmed in multivariate analyses after adjustment for other potentially prognostic factors. For patients treated with CAPEOX, there was no association between primary tumor location and outcome, neither in unadjusted nor adjusted analyses. CONCLUSIONS: The addition of bevacizumab to CAPEOX in first-line treatment of patients with mCRC may primarily benefit patients with primary tumors originating in the rectum and sigmoid colon. This hypothesis needs to be validated in data from completed randomized trials. CLINICALTRIALSGOV IDENTIFICATION NUMBER: NCT00212615.

Enhanced therapeutic effect of B cell-depleting anti-CD20 antibodies upon combination with in-situ dendritic cell vaccination in advanced lymphoma.

The present standard of care for B cell non-Hodgkin's lymphoma includes the anti-CD20 monoclonal antibody rituximab. Although combination treatments with chemotherapy and rituximab improved the duration of remissions and overall survival in indolent B cell lymphoma, the disease is essentially incurable. Thus, new therapeutic approaches are needed. One such approach is active immunization. Given that rituximab depletes both malignant and normal B cells, it is expected to impair humoral immune responses in vaccinated patients. Hence, optimal vaccination strategies for rituximab-treated patients require induction of effector T cells, which can be achieved by dendritic cell (DC) vaccines. We have demonstrated in a mouse model that chemotherapy combined with DC vaccines was therapeutically effective. However, efficacy was related to tumour size at the onset of treatment, decreasing in correlation with increasing tumour burdens. We therefore examined whether, in spite of its low efficacy in advanced disease, DC vaccination may synergize with anti-CD20 antibodies to enhance therapy. Lymphoma-bearing mice were treated with cyclophosphamide, anti-CD20 antibodies and an intratumoral DC vaccine. Results clearly demonstrated the enhanced therapeutic effect of this combination treatment. Thus, under conditions of disseminated disease, when either anti-CD20 antibody treatment or vaccination showed insufficient efficacy, their combination resulted in synergism that mediated long-term survival. We demonstrated further that the combination of antibody and vaccine induced T cell-mediated anti-tumour immune responses with long-term memory. Combination treatments including tumour cell-loaded DC vaccines may therefore provide a strategy for enhancing therapy in rituximab-treated patients.

Corpus callosum abnormalities, intellectual disability, speech impairment, and autism in patients with haploinsufficiency of ARID1B.

Corpus callosum abnormalities, intellectual disability, speech impairment, and autism in patients with haploinsufficiency of ARID1B. Corpus callosum abnormalities are common brain malformations with a wide clinical spectrum ranging from severe intellectual disability to normal cognitive function. The etiology is expected to be genetic in as much as 30-50% of the cases, but the underlying genetic cause remains unknown in the majority of cases. By next-generation mate-pair sequencing we mapped the chromosomal breakpoints of a patient with a de novo balanced translocation, t(1;6)(p31;q25), agenesis of corpus callosum (CC), intellectual disability, severe speech impairment, and autism. The chromosome 6 breakpoint truncated ARID1B which was also truncated in a recently published translocation patient with a similar phenotype. Quantitative polymerase chain reaction (Q-PCR) data showed that a primer set proximal to the translocation showed increased expression of ARID1B, whereas primer sets spanning or distal to the translocation showed decreased expression in the patient relative to a non-related control set. Phenotype-genotype comparison of the translocation patient to seven unpublished patients with various sized deletions encompassing ARID1B confirms that haploinsufficiency of ARID1B is associated with CC abnormalities, intellectual disability, severe speech impairment, and autism. Our findings emphasize that ARID1B is important in human brain development and function in general, and in the development of CC and in speech development in particular.

X-chromosome duplications in males with mental retardation: pathogenic or benign variants?

Studies to identify copy number variants (CNVs) on the X-chromosome have revealed novel genes important in the causation of X-linked mental retardation (XLMR). Still, for many CNVs it is unclear whether they are associated with disease or are benign variants. We describe six different CNVs on the X-chromosome in five male patients with mental retardation that were identified by conventional karyotyping and single nucleotide polymorphism array analysis. One deletion and five duplications ranging in size from 325 kb to 12.5 Mb were observed. Five CNVs were maternally inherited and one occurred de novo. We discuss the involvement of potential candidate genes and focus on the complexity of X-chromosomal duplications in males inherited from healthy mothers with different X-inactivation patterns. Based on size and/or the presence of XLMR genes we were able to classify CNVs as pathogenic in two patients. However, it remains difficult to decide if the CNVs in the other three patients are pathogenic or benign.

Further delineation of Pitt-Hopkins syndrome: phenotypic and genotypic description of 16 novel patients.

BACKGROUND: Haploinsufficiency of the gene encoding for transcription factor 4 (TCF4) was recently identified as the underlying cause of Pitt-Hopkins syndrome (PTHS), an underdiagnosed mental-retardation syndrome characterised by a distinct facial gestalt, breathing anomalies and severe mental retardation. METHODS: TCF4 mutational analysis was performed in 117 patients with PTHS-like features. RESULTS: In total, 16 novel mutations were identified. All of these proven patients were severely mentally retarded and showed a distinct facial gestalt. In addition, 56% had breathing anomalies, 56% had microcephaly, 38% had seizures and 44% had MRI anomalies. CONCLUSION: This study provides further evidence of the mutational and clinical spectrum of PTHS and confirms its important role in the differential diagnosis of severe mental retardation.

Molecular and clinical characterization of de novo and familial cases with microduplication 3q29: guidelines for copy number variation case reporting.

Microdeletions of 3q29 have previously been reported, but the postulated reciprocal microduplication has only recently been observed. Here, cases from four families, two ascertained in Toronto (Canada) and one each from Edinburgh (UK) and Leiden (Netherlands), carrying microduplications of 3q29 are presented. These families have been characterized by cytogenetic and molecular techniques, and all individuals have been further characterized with genome-wide, high density single nucleotide polymorphism (SNP) arrays run at a single centre (The Centre for Applied Genomics, Toronto). In addition to polymorphic copy-number variants (CNV), all carry duplications of 3q29 ranging in size from 1.9 to 2.4 Mb, encompassing multiple genes and defining a minimum region of overlap of about 1.6 Mb bounded by clusters of segmental duplications that is remarkably similar in location to previously reported 3q29 microdeletions. Consistent with other reports, the phenotype is variable, although developmental delay and significant ophthalmological findings were recurrent, suggesting that dosage sensitivity of genes located within 3q29 is important for eye and CNS development. We also consider CNVs found elsewhere in the genome for their contribution to the phenotype. We conclude by providing preliminary guidelines for management and anticipatory care of families with this microduplication, thereby establishing a standard for CNV reporting.

Advanced glycation end products and the absence of premature atherosclerosis in glycogen storage disease Ia.

INTRODUCTION: Despite their unfavourable cardiovascular risk profile, patients with glycogen storage disease type Ia (GSD Ia) do not develop premature atherosclerosis. We hypothesized that this paradox might be related to a decreased formation of advanced glycation end products (AGEs) resulting from lifetime low plasma glucose levels and decreased oxidative stress. METHODS: In 8 GSD Ia patients (age 20-34 years) and 30 matched controls we measured carotid intima-media thickness (IMT), skin autofluorescence (AF; a non-invasive index for AGEs), and specific AGEs (pentosidine, N-(carboxymethyl)lysine (CML), N-(carboxyethyl)lysine (CEL)) and collagen linked fluorescence (CLF, measured at excitation/emission wavelength combinations of 328/378 and 370/440 nm) in skin samples. RESULTS: Carotid IMT was significantly lower in GSD Ia patients. Skin AF did not differ between patients and controls. The skin samples showed higher CEL levels in the patient group (p = 0.008), but similar levels of pentosidine, CML, and CLF. In the total group, skin AF correlated with CML (r = 0.39, p = 0.031), CLF 328/378 nm (r = 0.53; p = 0.002) and CLF 370/440 nm (r = 0.60; p = 0.001). In the control group, AF also correlated with the maximum carotid IMT (r = 0.6; p = 0.004). CONCLUSION: Although our data confirm that GSD Ia patients present with a reduced burden of atherosclerosis, this phenomenon cannot be explained by differences in AGE accumulation as measured in the skin.

Congenital disorder of glycosylation type Ia presenting with hydrops fetalis.

There is a growing awareness that inborn errors of metabolism can be a cause of non-immune hydrops fetalis. The association between congenital disorders of glycosylation (CDG) and hydrops fetalis has been based on one case report concerning two sibs with hydrops fetalis and CDG-Ik. Since then two patients with hydrops-like features and CDG-Ia have been reported. Two more unrelated patients with CDG-Ia who presented with hydrops fetalis are reported here, providing definite evidence that non-immune hydrops fetalis can be caused by CDG-Ia. The presence of congenital thrombocytopenia and high ferritin levels in both patients was remarkable. These might be common features in this severe form of CDG. Both patients had one severe mutation in the phosphomannomutase 2 gene, probably fully inactivating the enzyme, and one milder mutation with residual activity, as had the patients reported in literature. The presence of one severe mutation might be required for the development of hydrops fetalis. CDG-Ia should be considered in the differential diagnosis of hydrops fetalis and analysis of PMM activity in chorionic villi or amniocytes should also be considered.

Investigation on the improvement of prediction by bootstrap model averaging.

OBJECTIVES: We illustrate a recently proposed two-step bootstrap model averaging (bootstrap MA) approach to cope with model selection uncertainty. The predictive performance is investigated in an example and in a simulation study. Results are compared to those derived from other model selection methods. METHODS: In the framework of the linear regression model we use the two-step bootstrap MA, which consists of a screening step to eliminate covariates thought to have no influence on the response, and a model-averaging step. We also apply the full model, variable selection using backward elimination based on Akaike's Information Criterion (AIC), the Bayes Information Criterion (BIC) and the bagging approach. The predictive performance is measured by the mean squared error (MSE) and the coverage of confidence intervals for the true response. RESULTS: We obtained similar results for all approaches in the example. In the simulation the MSE was reduced by all approaches in comparison to the full model. The smallest values are obtained for bootstrap MA. Only the bootstrap MA and the full model correctly estimated the nominal coverage. The backward elimination procedures led to substantial underestimation and bagging to an overestimation of the true coverage. The screening step of bootstrap MA eliminates most of the unimportant factors. CONCLUSION: The new bootstrap MA approach shows promising results for predictive performance. It increases practical usefulness by eliminating unimportant factors in the screening step.

Environmental enrichment in mice decreases anxiety, attenuates stress responses and enhances natural killer cell activity.

The importance of environment in the regulation of brain, behaviour and physiology has long been recognized in biological, social and medical sciences. Animals maintained under enriched conditions have clearly been shown to have better learning abilities than those maintained under standard conditions. However, the effects of environmental enrichment (EE) on immunity and emotionality have been less documented and remain questionable. Therefore, we investigated the effect of EE on natural killer (NK) cell activity, psychological stress responses and behavioural parameters. Male C3H mice were housed either in enriched or standard conditions for 6 weeks. Behaviour was then examined by the grip-strength test, staircase and elevated plus maze, and corticosterone levels and NK cell activity were measured. Furthermore, animals exposed to the stress paradigm, achieved by electric shock with reminders, were tested for freezing time in each reminder. Corticosterone levels were also measured. The EE mice showed decreased anxiety-like behaviour and higher activity compared to standard mice, as revealed by a greater percentage of time spent in the open arms of the elevated plus maze, and a higher rate of climbing the staircase. A shorter freezing time in the stress paradigm and no corticosterone level reactivity were measured in EE mice. In addition, NK cell activity in spleens of EE mice was higher than that demonstrated in those of standard mice. Thus, EE has a beneficial effect on anxiety-like behaviour, stress response and NK cell activity. The effect on NK cell activity is promising, due to the role of NK cells in host resistance.

Prenatal diagnosis and confirmation of the acrofacial dysostosis syndrome type Rodriguez.

The group of acrofacial dysostosis (AFD) syndromes is very heterogeneous and contains many different entities. In 1990, Rodriguez et al. [1990: Am J Med Genet 35:484-489] described a new type of AFD characterized by severe mandibular hypoplasia, phocomelia and oligodactyly of the upper limbs, absence of fibulae, microtia, cleft palate, internal organ anomalies including arrhinencephaly and abnormal lung lobulation, and early lethality. We describe another case of AFD type Rodriguez, identified by prenatal ultrasonography at 25 weeks of gestation.

Identification of a new HLA-A null allele, A*2436 N.

We describe a new HLA-A null allele in a donor. This null allele resulted from the deletion of two nucleotides in exon 2, which effects a frameshift as well as a premature stop codon. This new null allele has been officially named HLA-A*2436 N.

Early fetal anomaly scanning in a population at increased risk of abnormalities.

OBJECTIVES: To determine the effectiveness of early fetal anomaly scanning in a population at risk of fetal anomalies. DESIGN: A prospective study in a tertiary center of 101 consecutive fetuses at risk of congenital anomalies at 11-14 weeks of gestation. RESULTS: The principal (93/101 = 92%) reason for referral was having a previously affected infant. Nine (9/101 = 9%) fetuses were shown to have structural anomalies at the 11-14-week scan. In five of nine structurally affected fetuses, the nature of the anomalies was similar to that established in a previously affected pregnancy, four of which had a recurrence of an autosomal recessive syndrome. In two fetuses with a normal 11-14-week scan, anomalies were detected at the 18-21-week (arthrogryposis) or 30-week (cardiomyopathy) scans. CONCLUSIONS: The majority of fetal anomalies can be diagnosed in the late first/early second trimesters of pregnancy. This will be of particular advantage to those women who are at high risk of having affected offspring. However, as fetal anomalies may present at varying gestational ages, the standard 18-21-week scan cannot be abandoned. The effectiveness of the early pregnancy scan depends on the natural history of anomalies (gestational age at onset) and the variable phenotypic expression of anomalies/syndromes.

Unilateral multicystic dysplastic kidney: a combined pre- and postnatal assessment.

OBJECTIVE: To review the prenatal assessment of associated renal pathology, non-renal pathology and renal biometry, fetal outcome and postnatal urological management in the presence of unilateral fetal multicystic dysplastic kidney. METHODS: A total of 38 singleton pregnancies with fetal unilateral multicystic dysplastic kidney was studied over a 13-year period. Prenatally, fetal biometry, including head and abdominal circumferences and largest longitudinal diameter of the affected and contralateral kidneys, was performed. The amount of amniotic fluid was assessed. Fetal karyotyping was offered in cases of contralateral renal or non-renal pathology. A MAG 3 scan and voiding cystogram was performed approximately 4 weeks after delivery to establish renal function and to exclude urinary reflux. RESULTS: Unilateral fetal multicystic dysplastic kidney was left-sided in 53% and right-sided in 47% of cases. The fetus was male in 63% and female in 37% of cases. Associated renal and non-renal pathology existed in 21% and 5% of cases, respectively. The fetal karyotype in these subsets was always normal. The longitudinal diameter of the multicystic dysplastic kidney was above the 95th centile in 87%. There was polyhydramnios in three cases and oligohydramnios in two cases. The prematurity rate was 16%. Postnatal examination revealed a non-functional multicystic kidney in 87% (33/38) of cases. Following surgical removal of the affected kidney, these infants progressed normally. Of the remaining five infants, four died because of associated anomalies and one infant developed normally without surgery. CONCLUSIONS: Fetal outcome is determined by associated renal and/or non-renal structural pathology and not by the size/location of the unilateral multicystic dysplastic kidney or amniotic fluid volume.

Comparison of 1-hour and 3-hours paclitaxel infusion pharmacokinetics: results from a randomized trial.

PURPOSE: Aim of this study was to characterize the difference in pharmacokinetics (PK) of paclitaxel (PAC) after 1-h and 3-h infusion in humans and to define a pharmacodynamic relationship between PAC PK and myelotoxicity. PATIENTS AND METHODS: PAC PK were studied during the first PAC application in the first treatment cycle (1 treatment cycle = 6 PAC applications) in 25 patients. This patient group represents a subgroup of a large clinical study with neurotoxicity as primary endpoint. These 25 patients were those patients who were willing to give additional blood samples. The group size was sufficient for a full description of the PK of PAC. PAC was administered at 100 mg/m(2) weekly by 1-h (n = 12) or 3-h (n = 13) infusion to patients with advanced cancer (lung, breast, ovarian, cervix, and head and neck). Total PAC was quantified by high-performance liquid chromatography (HPLC). Pharmacokinetic parameters were calculated by noncompartmental and model-dependent methods. The leukocyte and neutrophil decrease during a 6-week treatment period was calculated by the percentage in decrease of white blood cell count (WBC) and absolute neutrophil count (ANC) as well as the area over the curve (AOC) of WBC and ANC. RESULTS: The area under the curve (AUC), the plasma clearance (Clp), the volume of distribution at steady state (V(ss)), the mean residence time (MRT) and the distribution half-life (t(1/2)) of PAC(tot) were not different in the two application modes. The elimination half-life (t1/2) and maximum plasma concentration C(max) were significantly different. No significant differences in the percentage of reduction of WBC and ANC were seen. Calculation of AOC of WBC showed a borderline significant difference (p = 0.0547) in case of WBC and no significant difference in case of ANC between the two PAC schedules. A considerable variance of AOC was observed. CONCLUSION: The pharmacokinetic study of total PAC of the two schedules investigated showed significant differences in the elimination half-life, which is longer in case of the 1-h infusion of PAC and in the maximum plasma concentration, which is higher in case of the 1-h infusion. The two schedules showed a similar myelotoxicity with a trend of less toxicity in the 1-h procedure.