Management of large peripheral nerve defects with autografting

INTRODUCTION

A segmental nerve defect from trauma results in significant loss of function of the extremity, and rarely occurs in isolation. Autografting of the nerve defect is the current gold standard.

METHODS

A review of the recent literature regarding peripheral nerve defects after trauma treated with autograft.

RESULTS

Identification of the zone of nerve injury is difficult and appropriate resection is critical for good outcomes. Meaningful recovery is more likely with application of excellent technique. Many of the factors affecting outcomes are not modifiable.

CONCLUSION

Nerve grafting for segmental nerve injuries continues to be an essential and appropriate treatment.

Differential interaction between DARC and SDF-1 on erythrocytes and their precursors

The Duffy Antigen Receptor for Chemokines (DARC) is expressed on erythrocytes and on endothelium of postcapillary venules and splenic sinusoids. Absence of DARC on erythrocytes, but not on endothelium, is referred to as the Duffy negative phenotype and is associated with neutropenia. Here we provide evidence that stromal cell-derived factor 1 (SDF-1), the chemokine that restricts neutrophil precursors to the bone marrow, binds to erythrocyte progenitors in a DARC-dependent manner. Furthermore, we show that SDF-1 binding to DARC is dependent on the conformation of DARC, which gradually changes during erythroid development, resulting in the absence of SDF-1 binding to mature erythrocytes. However, SDF-1 binding to erythrocytes was found to be inducible by pre-treating erythrocytes with IL-8 or with antibodies recognizing specific epitopes on DARC. Taken together, these novel findings identify DARC on erythrocyte precursors as a receptor for SDF-1, which may be of interest in beginning to understand the development of neutropenia in situations where DARC expression is limited.

Novel insights in the genomic organization and hotspots of recombination in the human KIR locus through analysis of intergenic regions

The Killer Immunoglobulin-like Receptor (KIR) proteins constitute a family of highly homologous surface receptors involved in the regulation of the innate cytotoxicity of natural killer (NK) cells. Within the human genome, 17 KIR genes are present, many of which show large variation across the population owing to the high number of allelic variants and copy number variation (CNV). KIR genotyping and CNV determination were used to map the KIR locus in a large cohort of >400 Caucasian individuals. Gene order and structure was determined by sequence-specific polymerase chain reaction of the intergenic regions. In this way, we could show that KIR3DL1 and KIR2DS4 gene variants are linked and that--contrary to current views--the gene KIR2DS5 is only present in the telomeric half of the KIR locus. Our study revealed novel insights in the highly organized distribution of KIR genes. Novel recombination hotspots were identified that contribute to the diversity of KIR gene distribution in the Caucasian population. Next-generation sequencing of the KIR intergenic regions allowed for a detailed single-nucleotide polymorphism analysis, which demonstrated several gene-specific as well as haplotype-specific nucleotides for a more accurate genotyping of this notoriously complex gene cluster.

The Fc gamma receptor IIa R131H polymorphism is associated with inhibitor development in severe hemophilia A

BACKGROUND

The development of factor (F) VIII neutralizing alloantibodies (inhibitors) is a major complication of treatment with FVIII concentrates in hemophilia A and the etiology is still poorly understood. The low-affinity Fc gamma receptors (FcγR), which are expressed on immune cells, provide an important link between cellular and humoral immunity by interacting with IgG subtypes. Genetic variations of the genes encoding FcγRs (FCGR genes) have been associated with susceptibility to infectious and autoimmune diseases.

OBJECTIVES

The aim of this study was to investigate the association between genetic variation of FCGR and inhibitor development in severe hemophilia A.

PATIENTS/METHODS

In this case-control study samples of 85 severe hemophilia A patients (siblings from 44 families) were included. Single nucleotide polymorphisms and copy number variation of the FCGR2 and FCGR3 gene cluster were studied in an FCGR-specific multiplex ligation-dependent probe amplification assay. Frequencies were compared in a generalized estimating equation regression model.

RESULTS

Thirty-six patients (42%) had a positive history of inhibitor development. The polymorphism 131R > H in the FCGR2A gene was associated with an increased risk of inhibitor development (odds ratio [OR] per H-allele, 1.8; 95% confidence interval [CI], 1.1-2.9). This association persisted in 29 patients with high titer inhibitors (OR per H-allele, 1.9; 95% CI, 1.2-3.2) and in 44 patients with the F8 intron 22 inversion (OR per H-allele, 2.6; 95% CI, 1.1-6.6).

CONCLUSIONS

Hemophilia A patients with the HH genotype of the FCGR2A polymorphism 131R > H have a more than 3-fold increased risk of inhibitor development compared with patients with the RR genotype.

Integrating cancer patients' perspectives into treatment decisions and treatment evaluation using patient-reported outcomes--a concept paper

Patient-reported outcomes are an important tool in clinical research. In the setting of cancer treatments, benefit of therapy is essentially characterised by improvement of survival as well as quality of life (QoL). A standardised instrument to assess QoL is the standardised QoL questionnaire of the European Organisation for Research and Treatment (EORTC QLQ-C30 questionnaire). QoL instruments provide data on different aspects (domains) of the framework of QoL. Using these questionnaires in studies provides data on how a treatment affects QoL in a group of patients. The goal of our concept is to individualise QoL and to use validated instruments in order to integrate patients' perspectives and aims into treatment assessment, planning and control. We propose to use the domains of the EORTC QLQ-C30 and to ask the patient to determine which objectives besides survival are relevant for him and should be achieved by treatment. These individual goals can be used in a process of shared decision-making to choose and monitor treatment. In clinical studies, this approach would allow to recruit more patients who would most probably benefit from the therapy. In addition, supportive data could be gathered in correlation to treatment goals and actual benefits.

Polymorphisms in chemokine receptor genes and susceptibility to Kawasaki disease

Kawasaki disease (KD) is an acute vasculitis occurring in young children. Its aetiology is unknown, but an infectious agent is assumed. Increased levels of proinflammatory cytokines and chemokines have been reported in KD. Genetic variation in these genes and the receptors for these genes could influence the regulation of cytokines and chemokines. In a case-control study of 170 Dutch Caucasian KD patients and 300 healthy Dutch Caucasian controls, common genetic variants in chemokine receptor genes CCR3, CCR2, CCR5, CX3CR1, CXCR1 and CXCR2 were analysed. Of the eight studied single nucleotide polymorphisms (SNPs) in the CCR3-CCR2-CCR5 gene cluster, four showed a significant association with susceptibility to KD. Moreover the CCR5-Delta32 was observed with an allele frequency of 10.7% in the control population compared to 6.5% in the KD patients (P = 0.04). Two haplotypes of the CCR3-CCR2-CCR5 gene-cluster appear to be at risk haplotypes for KD and one a protective haplotype. No association was observed with the studied SNPs in CX3CR1, CXCR1 and CXCR2. In conclusion, in a Dutch cohort of KD patients an association of KD occurrence with common genetic variants in the chemokine receptor gene-cluster CCR3-CCR2-CCR5 was observed.

The involvement of Fc gamma receptor gene polymorphisms in Kawasaki disease

Kawasaki disease is an acute febrile syndrome in infancy, characterized by vasculitis of medium-sized arteries. Without treatment the disease can lead to coronary artery lesions (CAL) in approximately 25% of the children. Therapy consists of intravenous immunoglobulins (IVIG), leading to a decrease of complications to 5-16%. Little is known about the working mechanisms of IVIG. In this study we evaluated the involvement of Fcgamma receptors (FcgammaRs) in Kawasaki disease by the determination of the frequency of known single nucleotide polymorphisms (SNPs) in the genes coding for the FcgammaRs and compared this with frequencies in a cohort of healthy controls. There was no difference in the distribution of the functionally relevant genotypes for FcgammaRIIa-131H/R, FcgammaRIIb-232I/T, FcgammaRIIIa-158 V/F and FcgammaRIIIb-NA1/NA2 between the patient group and the healthy controls. Furthermore, there were no polymorphisms linked to the disease severity as indicated by the absence or development of CAL during the disease. Altered transcription or expression of FcgammaR on specific cell types of the immune system may still play a role in susceptibility and treatment success, but at a level different from the functional SNPs in FcgammaR genes tested in this study.

Vascular endothelial growth factor gene haplotypes in Kawasaki disease

OBJECTIVE

To investigate whether common genetic variants in the vascular endothelial growth factor (VEGF) gene are associated with Kawasaki disease (KD) and the subsequent development of coronary artery lesions.

METHODS

Common genetic variants in the VEGF gene were analyzed in an association study in a Dutch cohort of 170 KD patients and 300 healthy Dutch Caucasian controls. Genotyping was done with 5'-nuclease TaqMan assays and 3'-hybridization-triggered fluorescence minor groove binder Eclipse assays.

RESULTS

An association with susceptibility to KD was observed with 2 of the 6 single-nucleotide polymorphisms analyzed in VEGF: -2594 A>C (rs699947) and the 236 bp 3' of STP C>T (rs3025039). Also for an 18-bp deletion in the promoter of VEGF a significant difference in the genotype and allele frequencies was observed between the KD patients and the controls. The haplotype CGCC (based on rs699947, rs2010963, rs25648, and rs3025039) was significantly associated with the development of KD (hap score 3.8; P = 0.0002). VEGF plasma levels were significantly higher in patients with the early phase of KD than in the healthy controls, and there was a trend toward higher VEGF plasma levels in KD patients with the -2594 CC and 236 bp 3' of STP CC genotypes.

CONCLUSION

Our results suggest that polymorphisms of the VEGF gene may play a role in the pathogenesis of KD.

The role of mannose-binding lectin (MBL) in paediatric oncology patients with febrile neutropenia

Children with cancer often have fever during chemotherapy-induced neutropenia, but only some develop serious infectious complications. Mannose-binding lectin (MBL) deficiency might increase infection susceptibility in these children. MBL genotype and phenotype were prospectively determined in 110 paediatric oncology patients. During febrile neutropenia, MBL concentrations were measured longitudinally in time. MBL genotype and phenotype were correlated to clinical and laboratory parameters. Structural exon-1 MBL2 mutations and the LX promoter polymorphism lead to deficient MBL concentrations. The capacity to increase MBL concentrations during febrile neutropenia was associated with MBL2 genotype. Infectious parameters did not differ between MBL-deficient and MBL-sufficient neutropenic children (n = 66). In contrast, MBL-sufficient patients had a greater risk of Intensive Care admittance (Relative Risk 1.6, 95% Confidence Interval 1.3-2.0, P = 0.04). MBL-deficient neutropenic children did not have more severe infections. However, most patients (61%) were severely neutropenic (<100 cells/microL), compromising the opsonophagocytic effector function of MBL. MBL substitution might still be beneficial in patients with phagocytic activity.

Functional characterization of mitochondria in neutrophils: a role restricted to apoptosis

Mitochondria are known to combine life-supporting functions with participation in apoptosis by controlling caspase activity. Here, we report that in human blood neutrophils the mitochondria are different, because they preserve mainly death-mediating abilities. Neutrophil mitochondria hardly participate in ATP synthesis, and have a very low activity of the tested marker enzymes. The presence of mitochondria in neutrophils was confirmed by quantification of mitochondrial DNA copy number, by detection of mitochondrial porin, and by JC-1 measurement of Deltapsi(m). During neutrophilic differentiation, HL-60 cells demonstrated a profound cytochrome c depletion and mitochondrial shape change reminiscent of neutrophils. However, blood neutrophils containing extremely low amounts of cytochrome c displayed strong caspase-9 activation during apoptosis, which was also observed in apoptotic neutrophil-derived cytoplasts lacking any detectable cytochrome c. We suggest that other proapoptotic factors such as Smac/DIABLO and HtrA2/Omi, which are massively released from the mitochondria, have an important role in neutrophil apoptosis.

XMCD study of the Ruddlesden-Popper Phase La1.2Nd0.2Sr1.6Mn2O7

X-ray Magnetic Circular Dichroism (XMCD) measurements of the Ruddlesden-Popper Phase La1,2Nd0,2Sr1.6Mn2O7 are reported. The Mn K. La and Nd L2,L3 edges have been measured on a powder sample at two different magnetic fields at low temperature. The analysis of the spectra at B = 1T indicates a large orbital moment of the Nd 5d-states and a significant spin-polarization of the La 5d-band. Furthermore at the Mn K-edge a XMCD-signal is observed, showing a polarization of the Mn 4p-band. At lower field (0.2T) all XMCD-signals are about two times smaller corresponding to the lower total magnetization. The signal at the Nd L2 edge vanishes completely at 0.2T.

A missense mutation in the heavy subunit of gamma-glutamylcysteine synthetase gene causes hemolytic anemia

gamma-Glutamylcysteine synthetase (GCS) catalyzes the initial and rate-limiting step in the biosynthesis of glutathione. gamma-GCS consists of a heavy and a light subunit encoded by separate genes. Hereditary deficiency of GCS has been reported in 6 patients with hemolytic anemia and low erythrocyte levels of glutathione and gamma-glutamylcysteine. In addition, 2 patients also had generalized aminoaciduria and developed neurologic symptoms. We have examined a Dutch kindred with 1 suspected case of GCS deficiency. The proband was a 68-year-old woman with a history of transient jaundice and compensated hemolytic anemia. One of her grandchildren was also GCS deficient; he was 11 years old and had a history of neonatal jaundice. The enzyme defect was confirmed and GCS activity was found to be less than 2% of normal in the erythrocytes of both patients. The complementary DNA (cDNA) for the heavy subunit of GCS was sequenced in these patients and in several members of the family. The proband and her GCS- deficient grandson were identified as homozygous for a 473C-->T substitution, changing codon 158 from CCC for proline into CTC for leucine. Several family members with half-normal GCS activity in their erythrocytes were heterozygous for the mutation.

Magnetocardiography in the diagnosis of fetal arrhythmia

OBJECTIVE

To examine the possible use of magnetocardiography in the diagnosis of fetal arrhythmias.

DESIGN

Investigation of routinely examined pregnant women, as well as women referred because of arrhythmias or other reasons.

PARTICIPANTS

Sixty-three women between the 13th and 42nd week of pregnancy.

METHODS

Recording of 189 fetal magnetocardiograms, of which 173 traces (92%) demonstrated sufficient fetal signal strength to permit evaluation. After digital subtraction of the maternal artefact, all fetal complexes were identified and the recording was examined for arrhythmic events.

RESULTS

Short bradycardic episodes, not associated with any pathological condition, were found in 26% of all recordings, usually in mid-pregnancy. In 12 cases, isolated extrasystoles of no clinical importance could be identified. There were nine traces which revealed multiple arrhythmias including ventricular and supraventricular ectopic beats, bigeminy and trigeminy, sino-atrial block and atrio-ventricular conduction disturbances. Furthermore, two cases with tachycardia were found.

CONCLUSION

Magnetocardiography offers a simple noninvasive method for examination of the fetal cardiac electrophysiological signal. It may thus be useful in the identification and classification of clinically relevant arrhythmia and aid in decisions concerning treatment.

[Recurrent pancreatitis in pediatric ulcerative colitis--a case report]

We report on a 12 years old girl with ulcerative colitis, who after a two years course of her disease developed a concomitant idiopathic pancreatitis. We discuss the causes of acute pancreatitis in childhood in view of the presented case summarizing the current literature. In the literature we found only two other children with ulcerative colitis and idiopathic pancreatitis. Both patients were colectomised as our patient did. Six months after colectomy she is still free of symptoms.

Flavin-dependent alcohol oxidase from yeast. Studies on the catalytic mechanism and inactivation during turnover

The kinetic course of the reaction of methanol and deutero-methanol with FAD-dependent alcohol oxidase was investigated under single-turnover conditions [kred approximately equal to 15000 min-1 (1H3COH) and approximately equal to 4300 min-1 (2H3COH)] and multiple-turnover conditions [TNmax approximately equal to 6000 min-1 (1H3COH) and approximately equal to 3100 min-1 (2H3COH)]. A kinetic scheme for the overall catalytic mechanism is proposed, which is characterized by (1) formation of a Michaelis complex between enzyme and substrate, (2) the reductive step involving partly rate-limiting scission of the substrate C-H bond, (3) reaction of the complex of reduced enzyme and aldehyde with dioxygen, and (4) a significant contribution of the dissociation rate of product from its complex with reoxidized enzyme to the overall rate. Prolonged turnover of various alcohols, including methanol, results in progressive inactivation of the enzyme by two processes. In the absence of catalase the inactivation rate increases with time due to accumulation of hydrogen peroxide, which is a potent inactivator (Kd approximately equal to 1.6 mM; kinact approximately equal to 0.55 min-1). In the presence of catalase inactivation during turnover is much slower, the process showing pseudo-first-order kinetics (Kinact approximately equal to 0.6 mM; kinact approximately equal to 0.005 min-1 with methanol). The ratio kcat/kinact varies with different alcohols but is always greater than 10(5). Propargyl alcohol and methylenecyclopropyl alcohol cannot be considered as suicide substrates, as compared to analogous substrates of other flavin oxidases.