A homologue of the Drosophila female sterile homeotic (fsh) gene in the class II region of the human MHC

The RING3 gene maps in the class II region of the human major histocompatibility complex, at a CpG island distal of the HLA-DNA gene. RING3 cDNAs were obtained from a T cell cDNA library and the longest (4 kb) was sequenced. The sequence contained an open reading frame encoding a protein of 754 amino acids. A screen of protein databases revealed striking homology between the RING3 protein and the Drosophila female sterile homeotic gene (fsh) which is implicated in the establishment of segments in the early embryo. Partial sequence homology was also observed with some other proteins involved in cell cycle control (CCG1), cell division (ftsA) and regulation of cell growth (gamma interferons). This highly conserved gene may play an important role in human development. In addition, its location in the MHC class II region may be related to some HLA-associated diseases.

Specific tumour-associated methylation in normal human term placenta and first-trimester cytotrophoblasts

Human placentation displays many similarities with tumourigenesis, including rapid cell division, migration and invasion, overlapping gene expression profiles and escape from immune detection. Recent data have identified promoter methylation in the Ras association factor and adenomatous polyposis coli tumour suppressor genes as part of this process. However, the extent of tumour-associated methylation in the placenta remains unclear. Using whole genome methylation data as a starting point, we have examined this phenomenon in placental tissue. We found no evidence for methylation of the majority of common tumour suppressor genes in term placentas, but identified methylation in several genes previously described in some human tumours. Notably, promoter methylation of four independent negative regulators of Wnt signalling has now been identified in human placental tissue and purified trophoblasts. Methylation is present in baboon, but not in mouse placentas. This supports a role for elevated Wnt signalling in primate trophoblast invasiveness and placentation. Examination of invasive choriocarcinoma cell lines revealed altered methylation patterns consistent with a role of methylation change in gestational trophoblastic disease. This distinct pattern of tumour-associated methylation implicates a coordinated series of epigenetic silencing events, similar to those associated with some tumours, in the distinct features of normal human placental invasion and function.

Ultrasound-guided radiofrequency ablation (RFA) for inoperable gastrointestinal liver metastases

PURPOSE

Surgery is the most effective treatment for liver metastases. Some patients, however, cannot tolerate this procedure due to co-morbidity, advanced age, site of the lesion or previous liver surgery. In our institution we have now increasing experience with radiofrequency ablation (RFA), a thermo-ablative modality. We compare our outcome and survival results to standard treatments for liver metastases.

MATERIALS AND METHODS

From April 2000 to June 2005, 30 consecutive patients with liver metastases from gastrointestinal primaries were treated with ultrasound guided RFA for their liver metastases (patients mean age 63.5 years, range 37-80. Size of lesions, range 0.4-6 cm). Main indications were non-operable lesions due to site of the lesion or co-morbidity. RFA was also applied as an additive to liver surgery and as a repetitive palliative treatment. 15 patients underwent one RFA-intervention, 8 patients two, 3 patients three, 1 patient four, 2 patients five and 1 patient six. RFA-interventions (n = 60) were performed either percutaneously (71.5%), in an open approach without liver surgery (22%) or in addition to liver surgery (6.5%).

RESULTS

Mean observation time after first RFA was 23.5 months (range 3-63). Median survival in our patient cohort is 34 months, which compares favourably with results obtained by hepatic resection, the standard of care for liver metastases. Complication rate, attributed to the RFA procedure, was small in our series (5.5%) with one pleural effusion and one abscess formation in the ablated lesion due to underlying bacteraemia.

CONCLUSION

RFA is an effective and low risk treatment modality in patients with liver metastases. The procedure is safe (complication rate < 6%) with low morbidity. RFA can be performed repeatedly on an outpatient basis with good palliative effects. Of note, surgery remains the treatment of choice in resectable liver metastases of colorectal origin.

The history of Seasonally Dry Tropical Forests in eastern South America: inferences from the genetic structure of the tree Astronium urundeuva (Anacardiaceae)

Today, the Seasonally Dry Tropical Forests (SDTF) of eastern South America occur as large, well-defined nuclei (e.g. Caatinga in the northeast) and as smaller enclaves within other vegetations (e.g. Cerrado and Chaco). In order to infer the way the present SDTF distribution was attained, the genetic structure of Astronium urundeuva, a tree confined to SDTF, was assessed using two chloroplast spacers and nine microsatellite loci. Five haplotypes were identified, whose distribution was spatially structured. The distribution of the two most common and divergent haplotypes suggested former vicariance and progressive divergence due to isolation. More recent range expansions of these two lineages subsequently occurred, leading to a secondary contact at the southern limit of the Caatinga SDTF nucleus. The multilocus-Bayesian approach using microsatellites consistently identified three groups of populations (Northeast, Central and Southwest). Isolation by distance was found in Northeast and Southwest groups whereas admixture was detected in the Central group, located at the transition between Caatinga and Cerrado domains. All together, the results support the existence of range expansions and secondary contact in the Central group. This study provides arguments that favour the existence of a previously more continuous formation of SDTF in eastern South America.

Workspace zone differentiation and visualization for virtual humans

Human performance measures such as discomfort and joint displacement play an important role in product design. The virtual human Santos, a new generation of virtual humans developed at the University of Iowa, goes directly to the computer-aided design model to evaluate a design, saving time and money. This paper presents an optimization-based workspace zone differentiation and visualization. Around the workspace of virtual humans, a volume is discretized to small zones and the posture prediction on each central point of the zone will determine whether the points are outside the workspace as well as the values of different objective functions. Visualization of zone differentiation is accomplished by showing different colours based on values of human performance measures on points that are located inside the workspace. The proposed method can subsequently help ergonomic design. For example, in a vehicle's interior, the controls should not only lie inside the workspace, but also in the zone that encloses the most comfortable points. Using the palette of colours inside the workspace as a visual guide, a designer can obtain a reading of the discomfort level of product users.

[A new adaptive hand prosthesis]

In the paper, a new adaptive hand prosthesis developed in the Institute of Applied Computer Sciences of the Forschungszentrum Karlsruhe is described. Starting from the state-of-the-art, the requirements of the hand prosthesis are derived and the realisation of the new prosthesis is shown. Finally the results obtained are discussed.

New autoantibodies in pediatric opsoclonus myoclonus syndrome

Opsoclonus-myoclonus syndrome (OMS) is a rare neurologic disorder comprising the main symptoms of eye-movement disturbances, muscle jerks, and severe ataxia. In children and adults, some cases are associated with a tumor as a paraneoplastic syndrome, whereas in children the paraneoplastic form is almost exclusively associated with neuroblastoma. The detection of autoantibodies in some OMS sera led to the hypothesis that the syndrome is of autoimmune origin. Beside autoantibodies against intracellular proteins, such as anti-Hu, alpha-enolase, and KHSRP, specific binding of autoantibodies to the surface of neuroblastoma cells and cerebellar granular neurons have been found. Antiproliferative and proapoptotic effects of these autoantibodies on neuroblastoma cell lines were noted as well. These results support the concept of a humoral autoimmune process in the pathogenesis of OMS.

Task-specific changes in motor evoked potentials of lower limb muscles after different training interventions

This study aimed to identify sites and mechanisms of long-term plasticity following lower limb muscle training. Two groups performing either a postural stability maintenance training (SMT) or a ballistic ankle strength training (BST) were compared to a non-training group. The hypothesis was that practicing of a self-initiated voluntary movement would facilitate cortico-spinal projections, while practicing fast automatic adjustments during stabilization of stance would reduce excitatory influence from the primary motor cortex. Training effects were expected to be confined to the practiced task. To test for training specificity, motor evoked potentials (MEP) induced by transcranial magnetic stimulation (TMS) were recorded at rest and during motor tasks that were similar to each training. Intracortical, cortico-spinal, as well as spinal parameters were assessed at rest and during these tasks. The results show high task and training specificity. Training effects were only observable during performance of the trained task. While MEP size was decreased in the SMT group for the trained tasks, MEP recruitment was increased in the BST group in the trained task only. The control group did not show any changes. Background electromyogram levels, M. soleus H-reflex amplitudes and intracortical parameters were unaltered. In summary, it is suggested that the changes of MEP parameters in both training groups, but not in the control group, reflect cortical motor plasticity. While cortico-spinal activation was enhanced in the BST group, SMT may be associated with improved motor control through increased inhibitory trans-cortical effects. Since spinal excitability remained unaltered, changes most likely occur on the supraspinal level.

The LRC haplotype project: a resource for killer immunoglobulin-like receptor-linked association studies

There is increasing evidence for epistatic interactions between gene products (e.g. KIR) encoded within the Leukocyte Receptor Complex (LRC) with those (e.g. HLA) of the Major Histocompatibility Complex (MHC), resulting in susceptibility to disease. Identification of such associations at the DNA level requires comprehensive knowledge of the genetic variation and haplotype structure of the underlying loci. The LRC haplotype project aims to provide this knowledge by sequencing common LRC haplotypes.

IgG subclass distribution of autoantibodies in pediatric opsoclonus–myoclonus syndrome

Opsoclonus-myoclonus syndrome (OMS) in children is a rare disorder including a severe eye movement disturbance, myoclonia, ataxia and often developmental retardation. Both OMS forms, idiopathic or neuroblastoma-associated (paraneoplastic), have been suspected to be autoimmune. Recently, autoantibodies have been found in OMS sera. We here show that autoantibodies in OMS, both intracellular and surface binding, belong mainly to the IgG3 subclass, although the total serum IgG3 level is normal. These results support the autoimmune hypothesis and point to a protein autoantigen as antigenic target.

Cortical and spinal adaptations induced by balance training: correlation between stance stability and corticospinal activation

AIM

To determine the sites of adaptation responsible for improved stance stability after balance (=sensorimotor) training, changes in corticospinal and spinal excitability were investigated in 23 healthy subjects.

METHODS

Neural adaptations were assessed by means of H-reflex stimulation, transcranial magnetic stimulation (TMS) and conditioning of the H-reflex by TMS (Hcond) before and after 4 weeks of balance training. All measurements were performed during stance perturbation on a treadmill. Fast posterior translations induced short- (SLR), medium- and long-latency responses (LLR) in the soleus muscle. Motor-evoked potential- (MEP) and Hcond-amplitudes as well as Hmax/Mmax ratios were determined at SLR and LLR. Postural stability was measured during perturbation on the treadmill.

RESULTS

Balance training improved postural stability. Hmax/Mmax ratios were significantly decreased at LLR. MEPs and Hcond revealed significantly reduced facilitation at LLR following training. A negative correlation between adaptations of Hcond and changes in stance stability was observed (r = -0.87; P < 0.01) while no correlation was found between stance stability and changes in Hmax/Mmax ratio. No changes in any parameter occurred at the spinally organized SLR and in the control group.

CONCLUSION

The decrease in MEP- and Hcond-facilitation implies reduced corticospinal and cortical excitability at the transcortically mediated LLR. Changes in cortical excitability were directly related to improvements in stance stability as shown by correlation of these parameters. The absence of such a correlation between Hmax/Mmax ratios and stance stability suggests that mainly supraspinal adaptations contributed to improved balance performance following training.

Training-Specific Adaptations of H- and Stretch Reflexes in Human Soleus Muscle

The authors investigated the effect of physical exercise on reflex excitability in a controlled intervention study. Healthy participants (N = 21) performed 4 weeks of either power training (ballistic strength training) or balance training (sensorimotor training [SMT]). Both training regimens enhanced balance control and rate of force development, whereas reductions in peak-to-peak amplitudes of stretch reflexes and in the ratio of the maximum Hoffman reflex to the maximum efferent motor response (Hmax:Mmax) measured at rest were limited to SMT. The differences in reflex excitability between the training regimens indicated different underlying neural mechanisms of adaptation. The reduced reflex excitability following SMT was most likely induced by supraspinal influence. The authors discuss an overall increase in presynaptic inhibition of Ia afferent fibers as a possible mechanism.

Screening for immunomodulatory proteins of the intestinal parasitic nematode Heligmosomoides polygyrus

Parasitic nematodes are constantly exposed to the immune effector mechanisms of their hosts. One strategy of the worms to cope with these defence reactions is the secretion of modulatory proteins that down-regulate cell-mediated immune responses. We analysed the proliferation of mesenteric lymph node cells of mice infected with Heligmosomoides polygyrus and showed that cellular proliferation was strongly suppressed in the chronic phase of infection. To identify proteins of H. polygyrus that are involved in parasite-induced immunomodulation, worm extract and culture supernatant of adult H. polygyrus were fractionated by gel chromatography and activity of each fraction was determined. One of the fractions (fraction 9) of worm extract as well as worm secretory products inhibited the antigen-specific cellular proliferation by about 40%. This reduced cellular reactivity coincided with a down-regulation of inducible nitric oxide production of mouse macrophages by 57%. Furthermore, fraction 9 contained antigens that were recognized by IgE antibodies of H. polygyrus-infected mice and induced degranulation of an IgE-sensitized basophil cell line. Single proteins of fraction 9 were analysed by mass spectrometry. These data suggest that antigens that are recognised by IgE antibodies might play an important role in immunomodulation exerted by nematode infections.

Upregulation of group IB secreted phospholipase A(2) and its M-type receptor in rat ANTI-THY-1 glomerulonephritis

Treatment of rat glomerular mesangial cell (GMC) cultures with pancreatic secreted phospholipase A(2) (sPLA(2)-IB) results in an enhanced expression of sPLA(2)-IIA and COX-2, possibly via binding to its specific M-type sPLA(2) receptor. In the current study, we have investigated the expression and regulation of sPLA(2)-IB and its receptor during glomerulonephritis (GN). In vivo we used the well-established rat model of anti-Thy 1.1 GN (anti-Thy 1.1-GN) to study the expression of sPLA(2)-IB and the M-type sPLA(2) receptor by immunohistochemistry. In addition, in vitro we determined the interkeukin (IL)-1beta-regulated mRNA and protein expression in primary rat glomerular mesangial and endothelial cells as well as in rat peripheral blood leukocytes (PBLs). Shortly after induction of anti-Thy 1.1-GN, sPLA(2)-IB expression was markedly upregulated in the kidney at 6-24 h. Within glomeruli, the strongest sPLA(2)-IB protein expression was detected on infiltrated granulocytes and monocytes. However, at the same time, the M-type receptor was also markedly upregulated on resident glomerular cells. In vitro, the most prominent cytokine-stimulated secretion of sPLA(2)-IB was observed in monocytes isolated from rat PBLs. Treating glomerular endothelial cells (GECs) with cytokines elicited only weak sPLA(2)-IB expression, but treatment of these cells with exogenous sPLA(2)-IB resulted in a marked expression of the endogenous sPLA(2)-IB. Mesangial cells did not express sPLA(2)-IB at all. The M-type sPLA(2) receptor protein was markedly upregulated on cytokine-stimulated mesangial and endothelial cells as well as on lymphocytes and granulocytes. During anti-Thy 1.1 rat GN, sPLA(2)-IB and the M-type sPLA(2) receptor are induced as primary downstream genes stimulated by inflammatory cytokines. Subsequently, both sPLA(2)-IB and the M-type sPLA(2) receptor are involved in the autocrine and paracrine amplification of the inflammatory process in different resident and infiltrating cells.

RPS6KA2, a putative tumour suppressor gene at 6q27 in sporadic epithelial ovarian cancer

We had previously defined by allele loss studies a minimal region at 6q27 (between D6S264 and D6S297) to contain a putative tumour suppressor gene. The p90 ribosomal S6 kinase-3 gene (p90 Rsk-3, RPS6KA2) maps in this interval. It is a serine-threonine kinase that signals downstream of the mitogen-activated protein kinase pathway. It is expressed in normal ovarian epithelium, whereas reduced or absent in tumours or cell lines. We show that RPS6KA2 is monoallelically expressed in the ovary suggesting that loss of a single expressed allele is sufficient to cause complete loss of expression in cancer cells. Further, we have identified two new isoforms of RPS6KA2 with an alternative start codon. Homozygous deletions were identified within the RPS6KA2 gene in two cell lines. Re-expression of RPS6KA2 in ovarian cancer cell lines suppressed colony formation. In UCI101 cells, the expression of RPS6KA2 reduced proliferation, caused G1 arrest, increased apoptosis, reduced levels of phosphorylated extracellular signal-regulated kinase and altered other cell cycle proteins. In contrast, small interfering RNA against RPS6KA2 showed the opposite effect in 41M cells. The above results suggest that RPS6KA2 is a putative tumour suppressor gene to explain allele loss at 6q27.