Maturation of the Human Cerebral Cortex During Adolescence: Myelin or Dendritic Arbor?

Previous in vivo studies revealed robust age-related variations in structural properties of the human cerebral cortex during adolescence. Neurobiology underlying these maturational phenomena is largely unknown. Here we employ a virtual-histology approach to gain insights into processes associated with inter-regional variations in cortical microstructure and its maturation, as indexed by magnetization transfer ratio (MTR). Inter-regional variations in MTR correlate with inter-regional variations in expression of genes specific to pyramidal cells (CA1) and ependymal cells; enrichment analyses indicate involvement of these genes in dendritic growth. On the other hand, inter-regional variations in the change of MTR during adolescence correlate with inter-regional profiles of oligodendrocyte-specific gene expression. Complemented by a quantitative hypothetical model of the contribution of surfaces associated with dendritic arbor (1631 m2) and myelin (48 m2), these findings suggest that MTR signals are driven mainly by macromolecules associated with dendritic arbor while maturational changes in the MTR signal are associated with myelination.

The Arf6 activator Efa6/PSD3 confers regional specificity and modulates ethanol consumption in Drosophila and humans.

Ubiquitously expressed genes have been implicated in a variety of specific behaviors, including responses to ethanol. However, the mechanisms that confer this behavioral specificity have remained elusive. Previously, we showed that the ubiquitously expressed small GTPase Arf6 is required for normal ethanol-induced sedation in adult Drosophila. Here, we show that this behavioral response also requires Efa6, one of (at least) three Drosophila Arf6 guanine exchange factors. Ethanol-naive Arf6 and Efa6 mutants were sensitive to ethanol-induced sedation and lacked rapid tolerance upon re-exposure to ethanol, when compared with wild-type flies. In contrast to wild-type flies, both Arf6 and Efa6 mutants preferred alcohol-containing food without prior ethanol experience. An analysis of the human ortholog of Arf6 and orthologs of Efa6 (PSD1-4) revealed that the minor G allele of single nucleotide polymorphism (SNP) rs13265422 in PSD3, as well as a haplotype containing rs13265422, was associated with an increased frequency of drinking and binge drinking episodes in adolescents. The same haplotype was also associated with increased alcohol dependence in an independent European cohort. Unlike the ubiquitously expressed human Arf6 GTPase, PSD3 localization is restricted to the brain, particularly the prefrontal cortex (PFC). Functional magnetic resonance imaging revealed that the same PSD3 haplotype was also associated with a differential functional magnetic resonance imaging signal in the PFC during a Go/No-Go task, which engages PFC-mediated executive control. Our translational analysis, therefore, suggests that PSD3 confers regional specificity to ubiquitous Arf6 in the PFC to modulate human alcohol-drinking behaviors.

EFhd2/Swiprosin-1 is a common genetic determinator for sensation-seeking/low anxiety and alcohol addiction.

In many societies, the majority of adults regularly consume alcohol. However, only a small proportion develops alcohol addiction. Individuals at risk often show a high sensation-seeking/low-anxiety behavioural phenotype. Here we asked which role EF hand domain containing 2 (EFhd2; Swiprosin-1) plays in the control of alcohol addiction-associated behaviours. EFhd2 knockout (KO) mice drink more alcohol than controls and spontaneously escalate their consumption. This coincided with a sensation-seeking and low-anxiety phenotype. A reversal of the behavioural phenotype with ß-carboline, an anxiogenic inverse benzodiazepine receptor agonist, normalized alcohol preference in EFhd2 KO mice, demonstrating an EFhd2-driven relationship between personality traits and alcohol preference. These findings were confirmed in a human sample where we observed a positive association of the EFhd2 single-nucleotide polymorphism rs112146896 with lifetime drinking and a negative association with anxiety in healthy adolescents. The lack of EFhd2 reduced extracellular dopamine levels in the brain, but enhanced responses to alcohol. In confirmation, gene expression analysis revealed reduced tyrosine hydroxylase expression and the regulation of genes involved in cortex development, Eomes and Pax6, in EFhd2 KO cortices. These findings were corroborated in Xenopus tadpoles by EFhd2 knockdown. Magnetic resonance imaging (MRI) in mice showed that a lack of EFhd2 reduces cortical volume in adults. Moreover, human MRI confirmed the negative association between lifetime alcohol drinking and superior frontal gyrus volume. We propose that EFhd2 is a conserved resilience factor against alcohol consumption and its escalation, working through Pax6/Eomes. Reduced EFhd2 function induces high-risk personality traits of sensation-seeking/low anxiety associated with enhanced alcohol consumption, which may be related to cortex function.

Genomic architecture of human neuroanatomical diversity.

Human brain anatomy is strikingly diverse and highly inheritable: genetic factors may explain up to 80% of its variability. Prior studies have tried to detect genetic variants with a large effect on neuroanatomical diversity, but those currently identified account for <5% of the variance. Here, based on our analyses of neuroimaging and whole-genome genotyping data from 1765 subjects, we show that up to 54% of this heritability is captured by large numbers of single-nucleotide polymorphisms of small-effect spread throughout the genome, especially within genes and close regulatory regions. The genetic bases of neuroanatomical diversity appear to be relatively independent of those of body size (height), but shared with those of verbal intelligence scores. The study of this genomic architecture should help us better understand brain evolution and disease.

Single nucleotide polymorphism in the neuroplastin locus associates with cortical thickness and intellectual ability in adolescents.

Despite the recognition that cortical thickness is heritable and correlates with intellectual ability in children and adolescents, the genes contributing to individual differences in these traits remain unknown. We conducted a large-scale association study in 1583 adolescents to identify genes affecting cortical thickness. Single-nucleotide polymorphisms (SNPs; n=54,837) within genes whose expression changed between stages of growth and differentiation of a human neural stem cell line were selected for association analyses with average cortical thickness. We identified a variant, rs7171755, associating with thinner cortex in the left hemisphere (P=1.12 × 10(-)(7)), particularly in the frontal and temporal lobes. Localized effects of this SNP on cortical thickness differently affected verbal and nonverbal intellectual abilities. The rs7171755 polymorphism acted in cis to affect expression in the human brain of the synaptic cell adhesion glycoprotein-encoding gene NPTN. We also found that cortical thickness and NPTN expression were on average higher in the right hemisphere, suggesting that asymmetric NPTN expression may render the left hemisphere more sensitive to the effects of NPTN mutations, accounting for the lateralized effect of rs7171755 found in our study. Altogether, our findings support a potential role for regional synaptic dysfunctions in forms of intellectual deficits.

Effectiveness of 0.05% oxymetazoline (Vicks Sinex Micromist®) nasal spray in the treatment of objective nasal congestion demonstrated to 12 h post-administration by magnetic resonance imaging.

INTRODUCTION: This study aimed to assess the qualitative and quantitative utility of MRI imaging to illustrate the magnitude and duration of the effect of a standard 100 µg dose of oxymetazoline in a commercially available formulation that also contains aromatic oils. METHODS: This was a randomized, open label, single dose, parallel group study in 21 adult male and female subjects who reported moderate to severe nasal congestion due to acute upper respiratory tract infection or hay fever. MRI scans were acquired using a 3T Philips Achieva scanner with a 16 channel head receive coil. High resolution MRI scans of the nasal turbinates were obtained immediately prior to dosing (baseline) and at approximately 1, 8, 10, 11, and 12 h after dosing. The efficacy variables of primary interest were inferior turbinate total volume at 8 and 12 h post-dosing. The secondary efficacy variables analysed were inferior turbinate total volume at 1, 10, and 11 h post-dosing, middle turbinate total volume at 1, 8, 10, 11, and 12 h post-dosing. RESULTS: Changes from baseline volumes measured for the inferior and middle turbinates of subjects receiving the oxymetazoline formulation showed significant (P < 0.05) decreases at all times up to and including 12 h post-administration. No significant decreases from baseline were detected in subjects receiving a sham 'spray' (untreated control - spray bottles with no spray solution). Statistical ANCOVA results of inferior and middle turbinate volume indicated significant differences (P < 0.05) at all measurement points up to and including 12 h post-administration between the oxymetazoline treatment group and the untreated control with the only exception the middle turbinate volume at 10 h (P = 0.0896). The significant changes were likely to be clinically relevant though this was not measured in the study. No AEs were reported during this study and no other safety evaluations were made. CONCLUSIONS: This study showed that MRI assessment of nasal congestion in human volunteers is a robust, repeatable and viable measurement technique. The application of a 100 µg Vicks Sinex Micromist(®) nasal decongestant (0.05% oxymetazoline solution) delivered a highly significant reduction in inferior and middle turbinate volumes compared with the application of a control, measurable by the MRI method up to and including a 12 h post-dose scan.

Mechanisms underlying the laxative effect of lactulose: A randomized placebo-controlled trial showing increased small bowel water and motility unaltered by the 5-HT3 receptor antagonist, ondansetron.

BACKGROUND: Lactulose is a laxative which accelerates transit and softens stool. Our aim was to investigate its mechanism of action and use this model of diarrhea to investigate the anti-diarrheal actions of ondansetron. METHODS: A double-blind, randomized, placebo-controlled crossover study of the effect of ondansetron 8 mg in 16 healthy volunteers. Serial MRI scans were performed fasted and 6 h after a meal. Participants then received lactulose 13.6 g twice daily and study drug for a further 36 h. On Day 3, they had further serial MRI scans for 4 h. Measurements included small bowel water content (SBWC), colonic volume, colonic gas, small bowel motility, whole gut transit, and ascending colon relaxation time (T1AC), a measure of colonic water content. KEY RESULTS: Lactulose increased area under the curve (AUC) of SBWC from 0 to 240 min, mean difference 14.2 L · min (95% CI 4.1, 24.3), p = 0.009, and substantially increased small bowel motility after 4 h (mean (95% CI) 523 (457-646) a.u. to 852 (771-1178) a.u., p = 0.007). There were no changes in T1AC after 36 h treatment. Ondansetron did not significantly alter SBWC, small bowel motility, transit, colonic volumes, colonic gas nor T1AC, with or without lactulose. CONCLUSION & INFERENCES: Lactulose increases SBWC and stimulates small bowel motility; however, unexpectedly it did not significantly alter colonic water content, suggesting its laxative effect is not osmotic but due to stimulation of motility. Ondansetron's lack of effect on intestinal water suggests its anti-diarrheal effect is not due to inhibition of secretion but more likely altered colonic motility.

Anti-leucocyte antibodies in platelet apheresis donors with and without prior immunizing events: implications for TRALI prevention.

BACKGROUND AND OBJECTIVES: Transfusion-related acute lung injury (TRALI) prevention strategies in platelet (PLT) apheresis donors focus on identifying antileucocyte antibody-positive donors. The use of microbead based assays for screening purposes is hampered by the lack of a consensus cut-off for TRALI prevention and the undefined role of anti-leucocyte antibodies in never-alloexposed donors. This study evaluated anti-leucocyte antibody assays in PLT apheresis donors with and without prior immunizing events with special focus on microbead assay cut-offs, antibody specificities and their potential significance in never-alloexposed donors. MATERIAL AND METHODS: Blood samples of male and female PLT apheresis donors with and without history of prior immunization were tested for anti-leucocyte antibodies. RESULTS: Of 262 female and 118 male PLT apheresis donors, 37·4% had prior immunizing events. Fifty-eight of 238 (24·4%) donors without prior immunizing event had anti-HLA antibodies confirmed in microbead single antigen assay (mean fluorescence intensity (MFI) >500). Even with a cut-off MFI >3000, anti-HLA antibodies were detected in 10·6% of female and 4·3% of male donors without history of immunization. Of the antibody specificities found, 6 of 17 (35·3%) anti-HLA-A, 4 of 8 (50·0%) anti-HLA-B and 4 of 6 (66·6%) anti-HLA class II antibodies have been detected in donors associated with TRALI cases in the literature. CONCLUSION: Platelet apheresis donors without history of immunization have anti-leucocyte antibodies that potentially can cause TRALI. In our opinion, this cohort should be included in screening strategies for TRALI prevention. As references and consensus cut-offs have not yet been established, it is premature to use microbead assays as standard for donor screening.

Measurement of fetal fat in utero in normal and diabetic pregnancies using magnetic resonance imaging.

OBJECTIVES: To assess the reliability of magnetic resonance imaging (MRI) to measure fetal fat volume in utero, and to study fetal growth in women with and without diabetes in view of the increased prevalence of macrosomia in the former. METHODS: We studied 26 pregnant women, 14 with pre-gestational diabetes and 12 non-diabetic controls. Fetal assessment took place at 24 weeks' gestation and again at 34 weeks by standard ultrasound biometry followed by MRI at 1.5 T. Fetal fat volume was determined from T1-weighted water-suppressed images using a semi-automated approach based on pixel intensity and taking into account partial volume effects. Fetal volume was also determined from the MRI images. Fetal weight was calculated using published fat and lean tissue densities. RESULTS: There was little fetal fat at 24 weeks' gestation, but at 34 weeks the fetal fat content was considerably higher in the women with diabetes, with a mean fat content of 1090 ± 417 cm(3) compared with 541 ± 348 cm(3) in the controls (P = 0.006). Measurements of fetal fat volume showed low intra- and interobserver variability at 34 weeks, with intraclass correlation coefficients consistently above 0.99. Birth-weight centile correlated with fetal fat volume (R(2) = 0.496, P < 0.001), percentage of fetal fat (R(2) = 0.362, P = 0.008) and calculated fetal weight (R(2) = 0.492, P < 0.001) at 34 weeks. CONCLUSIONS: MRI appears to be a promising tool for the determination of fetal fat, body composition and weight in utero during the third trimester of pregnancy.

4-dimensional local radial basis function interpolation of large, uniformly spaced datasets.

BACKGROUND AND OBJECTIVE: Large, uniformly spaced, complex and time varying datasets derived from high resolution medical image velocimetry can provide a wealth of information regarding small-scale transient physiological flow phenomena and pulsation of anatomical boundaries. However, there remains a need for interpolation techniques to effectively reconstruct a fully 4-dimensional functional relationship from this data. This paper presents a preliminary evaluation of a 4-dimensional local radial basis function (RBF) algorithm as a means of addressing this problem for laminar flows. METHODS: A 4D interpolation algorithm is proposed based on a Local Hermitian Interpolation (LHI) using a combination of multi-quadric RBF with a partition of unity scheme. The domain is divided into uniform sub-systems with size restricted to immediately neighbouring points. The validity of the algorithm is first established on a known 4D analytical dataset and a CFD based laminar flow phantom. Application is then demonstrated through characterisation of a large 4D laminar flow dataset obtained from magnetic resonance imaging (MRI) measurements of cerebrospinal fluid velocities in the brain. RESULTS: Performance of the algorithm is compared to that of a quad-linear interpolation, demonstrating favourable improvement in accuracy. The technique is shown to be robust, computationally efficient and capable of refined interpolation in Euclidean space and time. Application to MR velocimetry data is shown to produce promising results for the 4D reconstruction of the transient flow field and movement of the fluid boundaries at spatial and temporal locations intermediate to the original data. CONCLUSION: This study has demonstrated feasibility of an accurate, stable and efficient 4-dimensional local RBF interpolation method for large, transient laminar flow velocimetry datasets. The proposed approach does not suffer from ill-conditioning or high computational cost due to domain decomposition into local stencils where the RBF is only ever applied to a limited number of points. This work offers a potential tool to assist medical diagnoses and drug delivery through better understanding of physiological flow fields such as cerebrospinal fluid. Further work will evaluate the technique on a wider range of flow fields and against CFD simulation.

Measuring venous blood volume changes during activation using hyperoxia.

This study describes a novel method for measuring relative changes in venous cerebral blood volume (CBVv) using hyperoxia as a contrast agent. This method exploits the extravascular BOLD effect and its dependency on both task-related activation induced changes in venous blood oxygenation and changes due to breathing an oxygen enriched gas mixture. Changes in CBVv on activation can be estimated by comparing the change in transverse relaxation rate, R2*, due to hyperoxia in both baseline and activation states. Furthermore these measurements can be converted into a measure of the percentage change in CBVv. Experiments were performed to measure changes in a CBVv-weighted signal in response to a simple motor task. Both positive and negative changes in CBVv-weighted signal were detected in the positively activated BOLD region.

Investigating the effect of blood susceptibility on phase contrast in the human brain.

Recent work has shown a dramatic contrast between GM and WM in gradient echo phase images at high field (7 T). Although this contrast is key to the exploitation of phase in imaging normal and pathological tissue, its origin remains contentious. Several sources for this contrast have been considered including iron content, myelin, deoxy-hemoglobin, or water-macromolecule interactions. Here we quantify the contribution of intravascular dHb to the GM/WM contrast in the human brain at 7 T by modulating the susceptibility of the blood using a paramagnetic contrast agent. By carrying out high resolution, dynamic, gradient echo imaging before, during and after the injection of the contrast agent, we were able to follow the change in GM/WM phase contrast and to monitor simultaneously the susceptibility of the blood. Using these data in conjunction with the known susceptibility of venous blood we estimate the upper bound for the relative contribution of dHb in the vasculature to the measured GM/WM phase contrast to be 0.48 Hz for GM close to the pial surface, and 0.27 Hz for deeper GM. These values are up to 20% of the GM/WM phase difference observed in the human brain at 7 T. Furthermore, we found that the fractional blood volume differences required to account for the observed GM/WM phase contrast are 1.3% and 0.7% for GM close to the pial surface and for deeper GM, respectively.

Magnetization transfer phenomenon in the human brain at 7 T.

Magnetization transfer is an important source of contrast in magnetic resonance imaging which is sensitive to the concentration of macromolecules and other solutes present in the tissue. Magnetization transfer effects can be visualized in magnetization transfer ratio images or quantified via the z-spectrum. This paper presents methods of measuring the z-spectrum and of producing high-resolution MTR images and maps of z-spectrum asymmetry in vivo at 7 T, within SAR limits. It also uses a 3-compartment model to measure chemical exchange and magnetization transfer parameters from the z-spectrum data. The peak in the z-spectrum associated with chemical exchange between amide and water protons (amide proton transfer, APT, effects) is much more apparent at 7 T than at 3 T. Furthermore at 7 T quantitative APT results varied between the corpus callosum and other white matter structures, suggesting that quantitative APT imaging could be used as a method of measuring myelination. The results also suggest that chemical exchange is not responsible for the phase shift observed in susceptibility weighted images between grey matter and white matter.

An exploratory study of sunitinib plus paclitaxel as first-line treatment for patients with advanced breast cancer.

BACKGROUND: Sunitinib has shown single-agent activity in patients with previously treated metastatic breast cancer (MBC). We investigated the safety of the combination of sunitinib and paclitaxel in an exploratory study of patients with locally advanced or MBC. METHODS: Patients received oral sunitinib 25 mg/day (with escalation to 37.5 mg/day as tolerated) on a continuous daily dosing schedule and paclitaxel 90 mg/m(2) on days 1, 8, and 15 of each 28-day cycle. Study endpoints included safety (primary endpoint), pharmacokinetics, and antitumor activity. RESULTS: Twenty-two patients were enrolled. The most frequent adverse events (AEs) were fatigue/asthenia (77%), dysgeusia (68%), and diarrhea (64%). Grade 3 AEs included neutropenia (43%), fatigue/asthenia (27%), neuropathy (18%), and diarrhea (14%). No drug-drug interaction was observed on the basis of pharmacokinetic analysis. Of 18 patients with measurable disease at baseline, 7 (38.9%) achieved objective responses (including 2 complete and 5 partial responses). Clinical responses were observed in three of nine patients with triple-negative receptor status (estrogen receptor negative, progesterone receptor negative, and human epidermal growth factor receptor-2 negative). CONCLUSIONS: These data indicate that sunitinib and paclitaxel in combination are well tolerated in patients with locally advanced or MBC. No drug-drug interaction was detected and there was preliminary evidence of antitumor activity.

Fatal outcome of a hepatitis B virus transfusion-transmitted infection.

BACKGROUND AND OBJECTIVES: In 2008, hepatitis B virus (HBV) DNA testing was not yet mandatory for the screening of blood donations in Switzerland. At that time, HBsAg was the only specific mandatory marker for HBV. The importance of high sensitivity for HBV NAT screening is shown. MATERIALS AND METHODS: Donor and recipient of a transfusion-transmitted HBV infection were followed up. Multiple samples were tested for HBV serological and molecular markers. RESULTS: At donation, the donor appeared healthy, HBsAg was negative and had a normal ALAT level. Ten weeks later, clinical symptoms suggested acute HBV infection as was confirmed with positive HBsAg, HBeAg, anti-HBc IgG, anti-HBc IgM and anti-HBe. The archived sample from the original donation was negative for anti-HBc, but positive for HBV DNA (17 IU/ml). A recipient transfused with the red cell concentrate was HBV DNA positive (3100 IU/ml) 3 months post-transfusion. After five months, HBsAg, HBeAg, anti-HBc and HBV DNA (1.1 x 10(11) IU/ml) were positive. Two weeks later, the patient died from complications associated with HBV infection and his underlying bone marrow disease. CONCLUSIONS: The present case illustrates the importance of introducing highly sensitive HBV NAT screening strategy to prevent possible HBV transfusion-transmitted infections from donors with low viral load.

Syphilitic aneurysm.

Syphilis was once the most common cause of aortic aneurysm. For the last 60 years syphilis has been well controlled in the UK population. However, we present the recent case of a 52-year-old female black South African immigrant who was found to have a syphilitic aneurysm.

Perturbation of the BOLD response by a contrast agent and interpretation through a modified balloon model.

This study used an infusion of a paramagnetic contrast agent to perturb intravascular blood susceptibility and investigate its effect on the BOLD hemodynamic response. A three compartment BOLD signal model combined with a modified balloon model was developed to interpret the MR signal. This model incorporated arterial blood volume in order to simulate signal changes resulting from the contrast agent. The BOLD signal model was fitted to the experimental data to test the hypothesis that arterial blood volume changes during activation. It was found that allowing arterial blood volume to change, rather than assuming this change is negligible as often assumed in the literature, provides a better fit to the experimental data, particularly during the BOLD overshoot. The post-stimulus undershoot was fitted well, regardless of whether the arterial blood volume was allowed to change, by assuming that this feature is due to delayed venous compliance. However the resultant elevation in post-stimulus blood volume decays with an extremely long time constant, taking more than 55 s to recover to baseline following a 4.8 s stimulus. The post-stimulus signal changes measured here could alternatively be described by a post-stimulus elevation in metabolism. An alternative model of oxygen extraction, in place of the Oxygen Limitation model, would be required to test this hypothesis.

Implementation of quantitative perfusion imaging using pulsed arterial spin labeling at ultra-high field.

This study compares the implementation of the STAR and FAIR pulsed arterial spin labeling (PASL) schemes to form quantitative perfusion maps at ultra-high field, 7 Tesla (T), and high field, 3 T. Phantom experiments were performed to compare the inversion efficiency and profile of the labeling pulses at 7 T and 3 T and to optimize in-plane saturation techniques. The perfusion weighted (PW) signal was measured at a range of postlabeling delay times and quantitative perfusion maps were calculated on a voxel-by-voxel basis. An increase in PW signal was found with field strength, and together with the increased signal-to-noise ratio, this led to improved image signal-to-noise and quality of fit of perfusion maps at 7 T.

Molecular basis of the Rh antigen RH48 (JAL).

BACKGROUND AND OBJECTIVES: RH48 (JAL) is a low-incidence Rh antigen of unknown molecular background associated with weakened expression of RhCE antigens. The objective of this study was to establish the molecular basis of JAL. MATERIALS AND METHODS: Seventeen JAL+ samples, from seven black (one of them a Brazilian of mixed race: black/Caucasian), nine European Caucasians and one Asian individuals, were typed with anti-D, -C, -c, -E and -e. Some samples were also tested for V/VS and ce (f). Titration studies and flow cytometry were used to analyse the expression of the JAL antigen and genomic DNA sequencing of all RHCE exons was conducted on all samples. Routine genotyping for RHCE was carried out on all samples. Screening of RHD exons 1-10, which included detection of the DAU allele, was carried out on all except one of the black samples. The Caucasian samples and remaining black sample were screened for the DAU mutation 1136C>T (T379M). RESULTS: Six black individuals had the Dce haplotype with RHCE mutations 340C>T (R114W) and 733C>G (L245V) [V/VS] and the RHD mutation T379M [DAU]. One mixed race individual had the Dce haplotype with the RHCE mutation 340C>T (R114W) but without the V/VS or DAU mutation. Eight Caucasians had the DCe haplotype with the 340C>T mutation. One Caucasian and one Asian had the Dce haplotype with a different mutation in an adjacent nucleotide, 341G>A (R114Q). All Caucasian individuals were negative for the DAU mutation 1136C>T (T379M). Previously described weakness of CE-related Rh antigens when present in single dose on JAL+ samples of DCe and Dce haplotypes was observed. Weak expression of V/VS was observed in the three black samples tested and weakness of JAL was observed in the black samples compared to the Caucasian samples. CONCLUSION: The same mutation (340C>T, R114W) in two different haplotypes (DCe and Dce) and another mutation (341G>A, R114Q) in one of these haplotypes (Dce) are associated with expression of the JAL antigen. One of the RHCE mutations detected in our samples (340C>T) has been previously described but not in association with the JAL antigen. Our results indicate that the previously described RhCeMA and ce(s)(340) alleles encode the JAL antigen. Expression of V/VS antigen is weakened in the presence of JAL and expression of JAL is usually weaker when associated with the Dce haplotype compared to DCe.