NMDA-receptor antagonist and morphine decrease CRPS-pain and cerebral pain representation

A combination therapy of morphine with an NMDA-receptor antagonist might be more effective than morphine without a NMDA-receptor antagonist for the relief of neuropathic pain in patients with complex regional pain syndrome (CRPS). In order to test the efficacy of this combination therapy we performed a double-blind randomized placebo-controlled study on patients suffering from CRPS of the upper extremity. We used functional magnetic resonance imaging during movement of the affected and unaffected upper hand before and after a treatment regimen of 49 days that contrasted morphine and an NMDA-receptor antagonist with morphine and placebo. We postulated superior pain relief for the combination therapy and concomitant changes in brain areas associated with nociceptive processing. Only the combination therapy reduced pain at rest and during movement, and disability. After treatment, activation in the contralateral primary somatosensory (cS1) and anterior cingulate cortex was significantly reduced when the affected hand was moved. Pain relief during therapy was related to decreased activation in cS1 and secondary somatosensory cortex (S2). Our data suggest that the combination of morphine with an NMDA-receptor antagonist significantly affects the cerebral processing of nociceptive information in CRPS. The correlation of pain relief and decrease in cortical activity in cS1 and S2 is in accordance with the expected impact of the NMDA-receptor antagonist on cerebral pain processing with emphasis on sensory-discriminative aspects of pain.

Miniaturized transportable evaporator for molecule deposition inside cryogenic scanning probe microscopes

Here, we present a very small evaporator unit suitable to deposit molecules onto a sample in a cryogenic environment. It can be transported in an ultrahigh vacuum system and loaded into Omicron-type cantilever stages. Thus, molecule deposition inside a low temperature force microscope is possible. The design features an insulating base plate with two embedded electrical contacts and a crucible with low power consumption, which is thermally well isolated from the surrounding. The current is supplied via a removable power clip. Details of the manufacturing process as well as the used material are described. Finally, the performance of the whole setup is demonstrated.

The monomer-to-dimer transition and bimodal growth of Co-salen on NaCl(001): a high resolution atomic force microscopy study

Molecules of Co-salen, a paramagnetic metal-organic Schiff base complex, self-assemble into two different well ordered morphologies on a NaCl(001) substrate: nanowires, which form networks, and compact nanocrystallites. Their growth can be controlled by adjusting the deposition parameters. It turns out that the nanowires are metastable. Molecular resolution images suggest that the packing in both morphologies is the same as in bulk Co-salen single crystals. Only the orientation of the c-axis with respect to the substrate is different. The origin of this intriguing bimodal growth is associated with a monomer-to-dimer transition, which probably takes place during initial nucleation at step edges.

Real-time tissue elastography versus FibroScan for noninvasive assessment of liver fibrosis in chronic liver disease

PURPOSE

Transient elastography (FibroScan, [TE]) and serum fibrosis markers such as the FibroTest (FT) are established methods for the noninvasive staging of liver fibrosis. A study using real-time elastography (HI-RTE), which is integrated in a conventional ultrasound system, was recently published with comparable results to transient elastography. The aim of the present study was to validate real-time elastography using the formulas calculated in previous studies and to compare the results to transient elastography and FibroTest for the noninvasive assessment of liver fibrosis.

MATERIALS AND METHODS

One hundred and thirty-four patients with chronic liver disease and either histological assessment of liver fibrosis (n = 112) or proven liver cirrhosis (n = 22) were included in the study. All patients received TE, HI-RTE, and biochemical evaluation on the same day as presentation. The calculation of the elasticity score of real-time elastography was performed in accordance with the two previously published studies.

RESULTS

The Spearman correlation coefficient between transient elastography, real-time elastography and FibroTest with the histological Chevallier score was statistically significant with 0.78, 0.34, and 0.67, respectively (p < 0.01). The diagnostic accuracy expressed as areas under ROC curves was 0.84, 0.69 and 0.85 for the diagnosis of significant fibrosis (F > or = 2), and 0.97, 0.65, and 0.83 for the diagnosis of cirrhosis, respectively.

CONCLUSION

Real-time elastography in its present form cannot replace transient elastography for noninvasive assessment of liver fibrosis.

Towards an understanding of the atomic scale magnetic contrast formation in NC-AFM: a tip material dependent MExFM study on NiO(001)

Recently, magnetic exchange force microscopy (MExFM) was established as a new force microscopy based technique capable of imaging arrangements of magnetic moments with atomic resolution on NiO(001). However, before this final achievement many unsuccessful experiments were performed on this particular sample system, and it is still not entirely clear which factors are important to attain an atomic scale magnetic contrast. Varying the tip's magnetic properties, we investigate the contrast formation on NiO(001). Fe-, Ni- and Gd-coated tips yielded a chemical contrast between Ni and O atoms, but a magnetic signal between Ni atoms with magnetic moments pointing in the opposite direction could only be observed with out-of-plane sensitive Fe-coated tips. Our observations suggest that three factors are crucial to obtain a sufficiently large magnetic signal: (i) a large overlap between the spin-carrying electronic states, (ii) a collinear orientation between the magnetic moments and (iii) a large magnetic moment.

[Current problems of kidney transplantation]

The long-term problems after kidney transplantation have changed considerably in recent years. While formerly immunosuppression and prevention of acute rejection were of prime concern, now attention focuses on chronic alterations of the transplanted organ and long-term survival of the patients. The transplantation procedure itself has evolved into a standardized technique with a high level of surgical quality. Problems involving organ preservation and ischemia/reperfusion damage also play a role, especially in view of chronic aspects. Monitoring of long-term complications should follow a program for the transplanted organ as well as a program for the patient. Monitoring kidney function should address the organ more precisely than has previously been the case. Serum creatinine level and proteinuria alone provide insufficient information and only change long after cellular deterioration has begun. Hence it is imperative that new testing methods be developed. One possibility is offered by protocol biopsies that allow histological and molecular analysis of the kidney at regular intervals. The patient programs concentrate on diagnostics and treatment of the cardiovascular diseases. Furthermore, the patients must be screened for occurrence of neoplasia. There are no prospective studies covering all cardiovascular risk factors after kidney transplantation. This pertains particularly to the subject of hypertension.

Probing the magnetic exchange forces of iron on the atomic scale

Applying magnetic exchange force microscopy with an Fe-coated tip, we experimentally resolve the atomic-scale antiferromagnetic structure of the Fe monolayer on W(001). On the basis of first-principles calculations, using an Fe nanocluster as a tip, we determine the distance dependence of the magnetic exchange forces. Significant relaxation of tip and sample atoms occurs, which depend sensitively on the local magnetic configuration. This shifts the onset of magnetic interactions toward larger separations and facilitates their observation. Implementing a multiatom tip in the calculations and accounting for relaxation effects are crucial to obtain the correct sign and distance dependence of the magnetic exchange interaction. By comparison with our calculations, we show that the experimentally observed contrast is due to a competition between chemical and magnetic forces.

Acute tubular injury in protocol biopsies of renal grafts: prevalence, associated factors and effect on long-term function

Acute tubular injury (ATI) is commonly observed in renal allografts, especially early after transplantation. This study analyzes prevalence and associated clinical conditions of ATI in serial protocol biopsies (pBx) and indication biopsies (iBx), and its impact on long-term graft function. 612 pBx from 204 patients taken at 6 weeks, 3 and 6 months, and 151 iBx performed within the first year of transplantation were evaluated. Prevalence of ATI in pBx was 40% (6 weeks), 34% (3 months) and 37% (6 months), and 46% in iBx. ATI was associated with delayed graft function and prolonged cold ischemia time in pBx, and with acute rejections in iBx. The GFR at 1 and 2 years after transplantation correlated inversely with the frequency of ATI in both pBx and iBx (p < 0.001). Prevalence of chronic changes at 6 months was not significantly related to ATI (patients without ATI: 36%, patients with multiple ATI findings: 54%). ATI is linked to inferior long-term graft function. While this suggests lack of recovery from ATI with permanent allograft damage, the underlying molecular mechanisms need yet to be uncovered. Prevention of the potential pathogenetic factors identified in this study might be the key point to attain good long-term graft function.

Course and relevance of arteriovenous fistulas after renal transplant biopsies

Arteriovenous fistulas (AVFs) after renal transplant biopsy are considered harmless. However, verification of the clinical course has not been thoroughly documented. We evaluated the data of our outpatient renal transplant biopsy program regarding the clinical course of AVFs after 2824 biopsies since 2000. We also reviewed all selective renal transplant embolizations. AVFs were the most frequent biopsy complications (8.3%). Seventy-seven percent of AVFs disappeared spontaneously. Renal function in patients with AVFs was not different compared to those without during 2 years of observation. There were no differences in AVFs comparing protocol or indication biopsies, needle size, the time after transplantation, the use of acetylic salicylic acid or serum-creatinine at biopsy. Living or younger donors were less likely to get postbiopsy AVFs. Ten embolizations were performed. Only one patient was from our outpatient biopsy program. Nine others were biopsied as inpatients in the course of complications during 6 weeks after transplant. Six of nine successfully embolized patients profited with improvement of renal function. Large AVFs occur most commonly shortly after transplantation in patients with poor graft function. There is no established test predicting which patient will benefit from embolization; however, Doppler-determined resistive index may help in this regard.

Hepatitis C virus cell-cell transmission in hepatoma cells in the presence of neutralizing antibodies

Hepatitis C virus (HCV) infection of Huh-7.5 hepatoma cells results in focal areas of infection where transmission is potentiated by cell-cell contact. To define route(s) of transmission, HCV was allowed to infect hepatoma cells in the presence or absence of antibodies that neutralize cell-free virus infectivity. Neutralizing antibodies (nAbs) reduced cell-free virus infectivity by >95% and had minimal effect(s) on the frequency of infected cells in the culture. To assess whether cell-cell transfer of viral infectivity occurs, HCV-infected cells were cocultured with fluorescently labeled naïve cells in the presence or absence of nAbs. Enumeration by flow cytometry demonstrated cell-cell transfer of infectivity in the presence or absence of nAbs and immunoglobulins from HCV(+) patients. The host cell molecule CD81 and the tight junction protein Claudin 1 (CLDN1) are critical factors defining HCV entry. Soluble CD81 and anti-CD81 abrogated cell-free infection of Huh-7.5 and partially inhibited cell-cell transfer of infection. CD81-negative HepG2 hepatoma cells were resistant to cell-free virus infection but became infected after coculturing with JFH-infected cells in the presence of nAb, confirming that CD81-independent routes of cell-cell transmission exist. Further experiments with 293T and 293T-CLDN1 targets suggested that cell-cell transmission is dependent on CLDN1 expression.

CONCLUSION

These data suggest that HCV can transmit in vitro by at least two routes, cell-free virus infection and direct transfer between cells, with the latter offering a novel route for evading nAbs.

Treatment of Barrett's esophagus with argon plasma coagulation and antireflux surgery. A retrospective analysis

BACKGROUND/AIMS

The aim of this study was to assess the efficacy and the results of ablation of Barrett'esophagus by endoscopic argon plasma coagulation (APC) followed by fundoplication.

METHODOLOGY

Between January 1999 and December 2004, 21 patients with histological proven, short BE and scheduled for fundoplication, were treated by APC. Treatment was repeated until histological confirmation of complete ablation was obtained. All patients underwent surgical correction of reflux by Nissen fundoplication. Response to treatment was assessed at follow up with endoscopy every 6 to 12 months.

RESULTS

BE ablation was obtained in all patients after a mean of 3.6 APC sessions. There was no mortality and morbidity was 19% (4/21 patients). All patients underwent 360 degrees Nissen fundoplication as antireflux procedure. There was no operative mortality and no major complications requiring re-operation. Mean postoperative hospital stay was 7.9 days. Postoperatively 17/21 patients had at least one endoscopic control. The mean observation time was 17.5 months. Recurrence of Barrett epithelium was observed in 6 patients at a mean of 9.6 months after fundoplication.

CONCLUSIONS

Our results show that the combination of APC and fundoplication is a safe and effective treatment option for most patients with uncomplicated BE. Although no cancer development was observed, larger studies with a longer follow up are required to assess the impact of APC on cancer risk.