G protein-coupled receptor 40 expression in human melanoma - correlation with tumour thickness, AJCC stage and survival

BACKGROUND

In melanoma, preclinical data suggest a possible role of polyunsaturated fatty acids inhibiting cell growth. A new target molecule for free fatty acids, the G protein-coupled receptor GPR40, was identified in melanoma cells.

OBJECTIVES

The aim of this study was to investigate GPR40 expression in human melanocytic tissues and to evaluate its potential as a prognostic marker.

METHODS AND RESULTS

A total of 114 tissue sections of naevi, primary melanoma and melanoma metastasis were immunohistochemically stained with anti-GPR40. The staining was evaluated, using the immunoreactivity scoring system. Compared to naevi, primary melanoma and melanoma metastasis showed significantly higher levels of GPR40 (P < 0.05). In primary melanoma, GPR40 expression positively correlated with tumour thickness (P = 0.044) and AJCC level (P = 0.017) and in melanoma metastasis with AJCC level (P = 0.035). Primary melanoma patients with high levels of GPR40 had a significantly poorer overall survival (P = 0.004) and shorter disease-free survival (0.040).

CONCLUSION

The present study identified GPR40 as a novel target molecule in melanoma. First evidence for a potential role of the receptor in tumour progression and metastases was found, and it could be demonstrated that GPR40 expression is negatively correlated with patient's survival.

Formation of n- and p-type regions in individual Si/SiO2 core/shell nanowires by ion beam doping

A method for cross-sectional doping of individual Si/SiO₂ core/shell nanowires (NWs) is presented. P and B atoms are laterally implanted at different depths in the Si core. The healing of the implantation-related damage together with the electrical activation of the dopants takes place via solid phase epitaxy driven by millisecond-range flash lamp annealing. Electrical measurements through a bevel formed along the NW enabled us to demonstrate the concurrent formation of n- and p-type regions in individual Si/SiO₂ core/shell NWs. These results might pave the way for ion beam doping of nanostructured semiconductors produced by using either top-down or bottom-up approaches.

[Marginal protection of retinal cells by bisperoxovanadium : Appropriate therapy in the model of retinal ischemia?]

BACKGROUND

Ischemic processes usually lead to the destruction of retinal cells and therefore play a key role in a multitude of eye diseases.

OBJECTIVE

The aim of this study was to investigate whether bisperoxovanadium has a potential neuroprotective effect in an ischemia/reperfusion animal model.

MATERIAL AND METHODS

Initially, ischemia was induced in one eye of an ischemia/reperfusion model and 3 days later, a 14-day medication-based treatment was initiated. Bisperoxovanadium was administered intraperitoneally every 3 days. Subsequently, the number of ganglion cells, the rate of apoptosis, amacrine cells, macroglia, microglia, and their activation state, as well as photoreceptors were determined by histological and immunohistochemical analyses.

RESULTS

In comparison to the control group, a significant retinal ganglion cell loss, a significant reduction of the inner layers as well as a decrease in photoreceptor and amacrine cell numbers could be determined in the ischemic eyes. In addition, there was an increase in the number of microglia in these animals. The rats treated with bisperoxovanadium did not exhibit a significant neuroprotective effect regarding the number of ganglion cells, the rate of apoptosis, macroglia, amacrine cells, or photoreceptors; however, a low structural degeneration of photoreceptors could be observed as an effect of the treatment. Additionally, fewer microglia and activated microglia were observed after bisperoxovanadium treatment.

CONCLUSION

Bisperoxovanadium seems to have only a marginal neuroprotective effect on ischemic retinae. It needs to be examined whether earlier therapy onset, higher dose or different route of administration would significantly improve the results or whether this therapeutic approach is unsuitable.

Commensurate germanium light emitters in silicon-on-insulator photonic crystal slabs

We report on the fabrication and characterization of silicon-on-insulator (SOI) photonic crystal slabs (PCS) with commensurately embedded germanium quantum dot (QD) emitters for near-infrared light emission. Substrate pre-patterning defines preferential nucleation sites for the self-assembly of Ge QDs during epitaxial growth. Aligned two-dimensional photonic crystal slabs are then etched into the SOI layer. QD ordering enhances the photoluminescence output as compared to PCSs with randomly embedded QDs. Rigorously coupled wave analysis shows that coupling of the QD emitters to leaky modes of the PCS can be tuned via their location within the unit cell of the PCS.

ALD grown bilayer junction of ZnO:Al and tunnel oxide barrier for SIS solar cell

Various metal oxides are probed as extrinsic thin tunnel barriers in Semiconductor Insulator Semiconductor solar cells. Namely Al₂O₃, ZrO₂, Y₂O₃, and La₂O₃ thin films are in between n-type ZnO:Al (AZO) and p-type Si substrates by means of Atomic Layer Deposition. Low reverse dark current-density as low as 3×10^-7 A/cm², a fill factor up to 71.3%, and open-circuit voltage as high as 527 mV are obtained, achieving conversion efficiency of 8% for the rare earth oxide La₂O₃. ZrO₂ and notably Al₂O₃ show drawbacks in performance suggesting an adverse reactivity with AZO as also indicated by X-ray Photoelectron Spectroscopy.

Role of surface-segregation-driven intermixing on the thermal transport through planar Si/Ge superlattices

It has been highly debated whether the thermal conductivity κ of a disordered SiGe alloy can be lowered by redistributing its constituent species so as to form an ordered superlattice. By ab initio calculations backed by systematic experiments, we show that Ge segregation occurring during epitaxial growth can lead to κ values not only lower than the alloy's, but also lower than the perfect superlattice values. Thus we theoretically demonstrate that κ does not monotonically decrease as the Si- and Ge-rich regions become more sharply defined. Instead, an intermediate concentration profile is able to lower κ below both the alloy limit (total intermixing) and also the abrupt interface limit (zero intermixing). This unexpected result is attributed to the peculiar behavior of the phonon mean free path in realistic Si/Ge superlattices, which shows a crossover from abrupt-interface- to alloylike values at intermediate phonon frequencies of ∼3  THz. Our calculated κ's quantitatively agree with the measurements when the realistic, partially intermixed profiles produced by segregation are considered.

Hepatosplenic gamma-delta T-cell lymphoma in a female patient after delivery

Hepatosplenic γδ T-cell lymphoma (HSTCL) is a very rare peripheral T-cell lymphoma characterized by extranodal infiltration of mature malignant post-thymic T-lymphocytes into sinusoids of the liver and spleen without lymphadenopathy and significant cytopenias. The aetiology of the disease is unknown. We describe the case of a female patient in whom HSTCL developed after delivery and who was previously without disease. Flow cytometry and liver puncture are essential for diagnosing HSTCL, especially in patients with unexplained pancytopenia and hepatosplenomegaly. Since phenotypic results can easily be misinterpreted as non-malignant, the examiner should have enough experience to recognize clonal changes of T-lymphocytes. Namely, in contrast to B-lymphocytes, T-lymphocytes do not have an efficient indicator of clonality and are recognized by flow cytometry based only on aberrant expression of commonly present antigens of T-cell and NK-cell subsets. At present, there is no known cure for HSTCL with a maximum survival up to 2 years.

Long lasting remission by rituximab in a patient with primary cold agglutinin autoimmune haemolytic anaemia

A 76-year-old female patient with cold agglutinin autoimmune haemolytic anaemia (CAHA) is presented. The haemolysis worsened during infection. Earlier, the patient underwent an unsuccessful treatment with steroids, chlorambucil , folic acid and heated erythrocyte transfusion. We treated her with monoclonal anti-CD20 antibody Rituximab (RTX) weekly for four consecutive weeks. After three cycles, the signs of haemolysis slowly disappeared and haemoglobin completely normalized. We continued with the maintenance treatment with RTX every third month for 2 years. The patient is in complete remission. This case report emphasizes the importance of the use of RTX as a therapy for immune cytopenia. Patients with CAHA usually fail to respond to standard treatment. Since CAHA is a very rare condition, only some case reports and 2 studies reported on the positive effects of RTX. Although expensive, RTX has many advantages, such as quick and long-term efficiency and only a few side effects.

Detecting artery occlusion and critical flow diminution in the case of an acute ischemic stroke--methodological pitfalls of common vascular diagnostic methods

PURPOSE

None of the vascular emergency diagnostic methods commonly used in the case of acute ischemic stroke, i. e. CTA, color-coded duplex sonography (CCDS), MRA, and DSA, is free of restrictions due to physical and physiological characteristics. As a result, misleading results initiating an inappropriate acute therapeutic intervention or hampering a promising one cannot be excluded. We aimed to assess the type and frequency of methodological pitfalls occurring in this situation.

MATERIALS AND METHODS

We retrospectively analyzed data of 269 consecutive patients admitted to our stroke unit with a clinical syndrome of an acute stroke. All patients underwent one or more vascular emergency diagnostic methods on a routine basis.

RESULTS

37 patients were excluded because of a final diagnosis other than ischemic stroke. 76 of 232 ischemic stroke patients underwent emergency diagnostic methods with two or more vascular examination techniques. Controversial results occurred in 20 patients and related to the detection and localization of large artery occlusion and its differentiation from a low/slow flow situation and the identification of critical cerebral flow diminution distal to large artery occlusion/severe stenosis. Methodological pitfalls were able to be most reliably resolved by CCDS. Within the whole cohort of ischemic stroke patients, vascular constellations susceptible to misinterpretation were diagnosed in 40 (17.2 %) patients.

CONCLUSION

We recommend providing several techniques including CCDS in an emergency stroke setting and applying techniques with respect to diagnostic findings.

Deuterium nuclear magnetic resonance investigation of the effects of proteins and polypeptides on hydrocarbon chain order in model membrane systems

Deuterium Fourier-transform nuclear magnetic resonance spectra have been obtained of 1-myristoyl 2-(14,14,14-trideutero)myristoyl phosphatidylcholine bilayers at 34.1 MHz by using the quadrupole echo pulse technique. Thereby, we have investigated the effects upon the deuterated dimyristoyl phosphatidylcholine bilayers of the following proteins and polypeptides: gramicidin A, bacteriophage f1 coat protein, beef brain myelin proteolipid apoprotein, cytochrome b(5), and cytochrome c oxidase (ferrocytochrome c:oxygen oxidoreductase, EC 1.9.3.1). Above T(c), the transition temperature between the gel and liquid crystal phases, the quadrupole splitting of the deuterium-labeled methyl group is reduced or collapsed in the presence of protein or polypeptide. No evidence has been found for ordered "boundary lipid." Below T(c), the spectra show that the hydrocarbon chains are prevented from crystallizing by the protein (or polypeptide) incorporated in the membrane. Similar disordering effects above T(c) are also seen when an unsaturated lipid, 1-(16,16,16-trideutero)palmitoyl 2-palmitoleyl phosphatidylcholine is complexed with cytochrome oxidase.

Downbeat nystagmus: aetiology and comorbidity in 117 patients

OBJECTIVES

Downbeat nystagmus (DBN) is the most common form of acquired involuntary ocular oscillation overriding fixation. According to previous studies, the cause of DBN is unsolved in up to 44% of cases. We reviewed 117 patients to establish whether analysis of a large collective and improved diagnostic means would reduce the number of cases with "idiopathic DBN" and thus change the aetiological spectrum.

METHODS

The medical records of all patients diagnosed with DBN in our Neurological Dizziness Unit between 1992 and 2006 were reviewed. In the final analysis, only those with documented cranial MRI were included. Their workup comprised a detailed history, standardised neurological, neuro-otological and neuro-ophthalmological examination, and further laboratory tests.

RESULTS

In 62% (n = 72) of patients the aetiology was identified ("secondary DBN"), the most frequent causes being cerebellar degeneration (n = 23) and cerebellar ischaemia (n = 10). In 38% (n = 45), no cause was found ("idiopathic DBN"). A major finding was the high comorbidity of both idiopathic and secondary DBN with bilateral vestibulopathy (36%) and the association with polyneuropathy and cerebellar ataxia even without cerebellar pathology on MRI.

CONCLUSIONS

Idiopathic DBN remains common despite improved diagnostic techniques. Our findings allow the classification of "idiopathic DBN" into three subgroups: "pure" DBN (n = 17); "cerebellar" DBN (ie, DBN plus further cerebellar signs in the absence of cerebellar pathology on MRI; n = 6); and a "syndromatic" form of DBN associated with at least two of the following: bilateral vestibulopathy, cerebellar signs and peripheral neuropathy (n = 16). The latter may be caused by multisystem neurodegeneration.

Low recurrence rate of vestibular neuritis: a long-term follow-up

We examined 103 patients with vestibular neuritis (VN) in a follow-up study (5.7 to 20.5 years, mean 9.8 years). Two patients (1.9%) had developed a second occurrence of VN 29 to 39 months after the first. VN affected the contralateral ear in both and caused less severe distressing vertigo and postural imbalance. Unlike Bell's palsy and sudden hearing loss, a relapse in the same ear did not occur.

Multicolor-FISH applied to resolve complex chromosomal changes in a case of T-ALL (FAB L2)

We report on a patient with a clinically diagnosed acute lymphoblastic leukemia (ALL) with partial unrecorded complex translocation events especially involving chromosomes 5, 9 and 18. At the GTG-band level the karyotype was abnormal in 20% of the analyzed cells. The complex karyotype was studied in more detail by spectral karyotyping (SKY) and multicolor banding (MCB) to characterize it in more detail. Thus, the karyotype could be described very accurately and in summary three different clones were detected, reflecting a high rate of karyotypic evolution in this patient.

Growth characteristics of circulating hematopoietic progenitors in terminal renal failure

BACKGROUND

In patients with terminal renal failure, the most frequently noted hematological change is normocytic normochromic anemia. As not all anemic patients respond in the same way to treatment with human erythropoietin, the aim of our investigation was to confirm the hypothesis that the origin of this anemia is multifactorial.

MATERIAL/METHODS

Therefore we cultivated peripheral blood CFU GEMM, CFU GM, and BFU E in 65 patients treated by hemodialysis, subdivided in two groups according to creatinine concentration (Group 1: <900 micromol/l, Group 2: >900 micromol/l). Hematopoietic stem cells were cultivated on methylcellulose with growth factors added.

RESULTS

Growth inhibition of BFU E and CFU GM and a negative correlation between CFU GEMM, CFU GM, and BFU E growth and urea concentration were found in the entire group of patients. CFU GEMM growth in Group 2 was inhibited. Positive correlation between CFU GM and BFU E, CFU GEMM and BFU E, and CFU GM and CFU GEMM growth was established. In Group 1 a negative correlation between BFU E and CFU GM growth and creatinine concentration was found, and in Group 2 a negative correlation between BFU E and CFU GM growth and urea concentration.

CONCLUSIONS

Relatively decreased erythropoietin concentration is one of the major causes of renal anemia. As CFU GM and CFU GEMM growth was decreased, hematopoiesis must be disturbed at a higher level and is affected by other factors connected with uremia, such as the lack of T(4) lymphocytes and the dialysis procedure.

[The most common form of dizziness in middle age: phobic postural vertigo]

Up to now, there have been only a few valid epidemiological investigations of dizziness or vertigo as key symptoms. According to an analysis of 4,214 patients examined between 1989 and 2002 in an outpatient dizziness unit, benign peripheral paroxysmal positional vertigo (BPPV) and phobic postural vertigo (PPV) constitute the two most frequent syndromes. In this study, the relative age and sex distribution of both disorders was analysed. In the age group from 20 to 50 years, PPV was comparatively the most frequent form of dizziness, with a share of 22% to 26%. When left untreated, PPV becomes chronic in most cases and leads to considerable impairments, also at work. However, when diagnosed correctly, it can be treated successfully in more than 70% of cases. Thus, it takes on considerable medical and socioeconomic significance and should be part of the diagnostic repertoire of every doctor.

In vitro selectivity, in vivo biodistribution and tumour uptake of annexin V radiolabelled with a positron emitting radioisotope

The availability of a noninvasive method to detect and quantify apoptosis in tumours will enable tumour response to several cancer therapies to be assessed. We have synthesised two radiotracers, annexin V and the N-succinimidyl-3-iodobenzoic acid (SIB) derivative of annexin V, labelled with radio-iodine (¹²⁴I and ¹²⁵I) and provided proof of the concept by assessing specific binding and biodistribution of these probes to apoptotic cells and tumours. We have also assessed the tumour uptake of [¹²⁴I]annexin V in a mouse model of apoptosis. RIF-1 cells induced to undergo apoptosis in vitro showed a drug concentration-dependent increased binding of [¹²⁵I]annexin V and [¹²⁵I]SIB–annexin V. In the same model system, there was an increase in terminal deoxynucleotidyl transferase-mediated nick end labelling (TUNEL)-positive cells and a decrease in clonogenic survival. Radiotracer binding was completely inhibited by preincubation with unlabelled annexin V. In RIF-1 tumour-bearing mice, rapid distribution of [¹²⁵I]SIB–annexin V-derived radioactivity to kidneys was observed and the radiotracer accumulated in urine. The binding of [¹²⁵I]SIB–annexin V to RIF-1 tumours increased by 2.3-fold at 48 h after a single intraperitoneal injection of 5-fluorouracil (165 mg kg⁻¹ body weight), compared to a 4.4-fold increase in TUNEL-positive cells measured by immunostaining. Positron emission tomography images with both radiotracers demonstrated intense localisation in the kidneys and bladder. Unlike [¹²⁴I]SIB–annexin V, [¹²⁴I]annexin V also showed localisation in the thyroid region presumably due to deiodination of the radiolabel. [¹²⁴I]SIB–annexin V is an attractive candidate for in vivo imaging of apoptosis by PET.

Anterior canal failure: ocular torsion without perceptual tilt due to preserved otolith function

A patient with anterior semicircular canal dehiscence syndrome underwent surgical patching that caused an isolated dysfunction of the left anterior semicircular canal postoperatively. He exhibited significant ocular torsion toward the side of the affected labyrinth (17 degrees excyclotropia of the ipsilateral eye), but no displacement of the subjective visual vertical. This dissociation suggests that an isolated ocular torsion may occur after an anterior semicircular canal lesion. A combined ocular torsion and subjective visual vertical tilt, which is usually seen with vestibular lesions, requires an associated otolith dysfunction.