The upgraded TOMAS device: A toroidal plasma facility for wall conditioning, plasma production, and plasma-surface interaction studies

The Toroidal Magnetized System device has been significantly upgraded to enable development of various wall conditioning techniques, including methods based on ion and electron cyclotron (IC/EC) range of frequency plasmas, and to complement plasma-wall interaction research in tokamaks and stellarators. The toroidal magnetic field generated by 16 coils can reach its maximum of 125 mT on the toroidal axis. The EC system is operated at 2.45 GHz with up to 6 kW forward power. The IC system can couple up to 6 kW in the frequency range of 10 MHz-50 MHz. The direct current glow discharge system is based on a graphite anode with a maximum voltage of 1.5 kV and a current of 6 A. A load-lock system with a vertical manipulator allows exposure of material samples. A number of diagnostics have been installed: single- and triple-pin Langmuir probes for radial plasma profiles, a time-of-flight neutral particle analyzer capable of detecting neutrals in the energy range of 10 eV-1000 eV, and a quadrupole mass spectrometer and video systems for plasma imaging. The majority of systems and diagnostics are controlled by the Siemens SIMATIC S7 system, which also provides safety interlocks.

Modified Peritoneal Flap Hernioplasty Versus Retromuscular Technique for Incisional Hernia Repair: a Retrospective Cohort Study

BACKGROUND AND AIMS

We present an open retromuscular mesh technique for incisional hernia repair, the modified peritoneal flap hernioplasty, where the fascia is sutured to the mesh and the hernia sac utilized for anterior mesh coverage. The aim was to describe the modified peritoneal flap hernioplasty technique and to compare it to a retromuscular repair, without component separation, regarding short-term complications, patient satisfaction, abdominal wall complaints, and recurrent incisional hernia.

MATERIALS AND METHODS

Consecutive patients operated electively with modified peritoneal flap hernioplasty technique (December 2012-December 2015) or retromuscular technique (Jan 2011-Oct 2014) were included in a retrospective single-center cohort study. Outcomes were evaluated from the Swedish Ventral Hernia Registry, by chart review, physical examination, and an abdominal wall complaints questionnaire.

RESULTS

The modified peritoneal flap hernioplasty group (n = 78) had larger hernias (mean width 10.4 vs 8.5 cm, p = 0.005), more advanced Centers for Disease Control classification (p = 0.009), and more simultaneous gastrointestinal-tract surgery (23.1% vs 11.5%, p = 0.041) than the retromuscular group (n = 96). No difference in short-term complications was seen. Incisional hernia recurrence was lower in the modified peritoneal flap hernioplasty group (1.4% vs 10.3%, p = 0.023), and patients were more satisfied (93.8% vs 81.7%, p = 0.032). Follow-up time was shorter in the modified peritoneal flap hernioplasty group (614 vs 1171 days, p < 0.001).

CONCLUSION

This retrospective study showed similar rates of short-term complications, despite more complex hernias in the modified peritoneal flap hernioplasty group. Furthermore, a lower incisional hernia recurrence rate for the modified peritoneal flap hernioplasty technique compared with the retromuscular technique used in our department was found. If this holds true with equally long follow-up remains to be proven.

Vacuum-Assisted Wound Closure and Permanent Onlay Mesh-Mediated Fascial Traction: A Novel Technique for the Prevention of Incisional Hernia after Open Abdomen Therapy Including Results From a Retrospective Case Series

BACKGROUND AND AIMS

Incisional hernia development is a frequent long-term sequel after open abdomen treatment. This report describes a novel technique, the vacuum-assisted wound closure and permanent onlay mesh-mediated fascial traction for temporary and final closure of the open abdomen, with the intention to decrease incisional hernia rates. Primary aim was to evaluate incisional hernia development and secondary aims to describe short-term complications and patient-reported outcome.

MATERIALS AND METHODS

The basics of the technique is an onlay mesh, applied early during open abdomen treatment by suturing to the fascia in two rows with a 3- to 4-cm overlap from the midline incision, used for traction and kept for reinforced permanent closure. A retrospective case series, including chart review, evaluation of computed tomography/ultrasound images, and an out-patient clinical examination were performed. The patients were asked to answer a modified version of the ventral hernia pain questionnaire.

RESULTS

A total of 11 patients were treated with vacuum-assisted wound closure and permanent onlay mesh-mediated fascial traction with median follow-up of 467 days. Fascial closure rate was 100% and 30 day mortality 0%. Two of nine patients, eligible for incisional hernia follow-up, developed a hernia. Neither of the hernias were symptomatic nor clinically detectable. Six of 10 patients eligible for short-term follow-up had a prolonged wound-healing time exceeding 3 weeks. One of seven patients eligible for patient-reported outcome have had pain during the last week.

CONCLUSION

The vacuum-assisted wound closure and permanent onlay mesh-mediated fascial traction is a promising new technique for open abdomen treatment and reinforced fascial closure. The results of the first 11 patients treated with this technique show a low incisional hernia rate with manageable short-term wound complications and few patient-reported disadvantages.

The translationally relevant mouse model of the 15q13.3 microdeletion syndrome reveals deficits in neuronal spike firing matching clinical neurophysiological biomarkers seen in schizophrenia

Aim

To date, the understanding and development of novel treatments for mental illness is hampered by inadequate animal models. For instance, it is unclear to what extent commonly used behavioural tests in animals can inform us on the mental and affective aspects of schizophrenia.

Methods

To link pathophysiological processes in an animal model to clinical findings, we have here utilized the recently developed Df(h15q13)/+ mouse model for detailed investigations of cortical neuronal engagement during pre‐attentive processing of auditory information from two back‐translational auditory paradigms. We also investigate if compromised putative fast‐spiking interneurone (FSI) function can be restored through pharmacological intervention using the Kv3.1 channel opener RE1. Chronic multi‐array electrodes in primary auditory cortex were used to record single cell firing from putative pyramidal and FSI in awake animals during processing of auditory sensory information.

Results

We find a decreased amplitude in the response to auditory stimuli and reduced recruitment of neurones to fast steady‐state gamma oscillatory activity. These results resemble encephalography recordings in patients with schizophrenia. Furthermore, the probability of interneurones to fire with low interspike intervals during 80 Hz auditory stimulation was reduced in Df(h15q13)/+ mice, an effect that was partially reversed by the Kv3.1 channel modulator, RE1.

Conclusion

This study offers insight into the consequences on a neuronal level of carrying the 15q13.3 microdeletion. Furthermore, it points to deficient functioning of interneurones as a potential pathophysiological mechanism in schizophrenia and suggests a therapeutic potential of Kv3.1 channel openers.

Discrepancies between cortical and behavioural long-term readouts of hyperalgesia in awake freely moving rats

Background

It is still unclear to what extent the most common animal models of pain and analgesia, based on indirect measures such as nocifensive behaviours, provide valid measures of pain perception.

Methods

To address this issue, we developed a novel animal model comprising a more direct readout via chronically (>1 month) implanted multichannel electrodes (MCE) in rat primary somatosensory cortex (S1; known to be involved in pain perception in humans) and compared this readout to commonly used behavioural pain‐related measures during development of hyperalgesia. A translational method to induce hyperalgesia, UVB irradiation of the skin, was used. Localized CO₂ laser stimulation was made of twenty skin sites (20 stimulations/site/observation day) on the plantar hind paw, before and during the time period when enhanced pain perception is reported in humans after UVB irradiation.

Results

We demonstrate a 2–10 fold significant enhancement of cortical activity evoked from both irradiated and adjacent skin and a time course that corresponds to previously reported enhancement of pain magnitude during development of primary and secondary hyperalgesia in humans. In contrast, withdrawal reflexes were only significantly potentiated from the irradiated skin area and this potentiation was significantly delayed as compared to activity in S1.

Conclusions

The present findings provide direct evidence that chronic recordings in S1 in awake animals can offer a powerful, and much sought for, translational model of the perception of pain magnitude during hyperalgesia.

What does this study add?

In a novel animal model, chronic recordings of nociceptive activity in primary somatosensory cortex (S1) in awake freely moving rats are compared to behavioural readouts during UVB‐induced hyperalgesia. Evoked activity in rat S1 replicates altered pain perception in humans during development of hyperalgesia, but withdrawal reflexes do not.

Wound dehiscence: outcome comparison for sutured and mesh reconstructed patients

PURPOSE

Treatment guidelines for abdominal wound dehiscence (WD) are lacking. The primary aim of the study was to compare suture to mesh repair in WD patients concerning incisional hernia incidence. Secondary aims were to compare recurrent WD, morbidity, mortality and long-term abdominal wall complaints.

METHODS

A retrospective chart review of 46 consecutive patients operated for WD between January 2010 and August 2012 was conducted. Physical examination and a questionnaire enquiry were performed in January 2013.

RESULTS

Six patients were treated by vacuum-assisted wound closure and mesh-mediated fascial traction (VAWCM) before definitive closure. Three patients died early resulting in 23 patients closed by suture and 20 by mesh repair. Five sutured, but no mesh repair patients had recurrent WD (p = 0.051) with a mortality of 60 %. Finally, 18 sutured and 21 mesh repair patients were eligible for follow-up. The incidence of incisional hernia was higher for the sutured patients (53 vs. 5 %, p = 0.002), while mesh repair patients had a higher short-term morbidity rate (76 vs. 28 %, p = 0.004). Abdominal wall complaints were rare in both groups.

CONCLUSIONS

Suture of WD was afflicted with a high incidence of recurrent WD and incisional hernia formation. Mesh repair overcomes these problems at the cost of more wound complications. VAWCM seems to be an alternative for treating contaminated patients until definitive closure is possible. Long-term abdominal wall complaints are uncommon after WD treatment.

Phosphate buffers in capillary electrophoresis/mass spectrometry using atmospheric pressure photoionization and electrospray ionization

Capillary electrophoresis (CE) has been combined with atmospheric pressure photoionization (APPI) and electrospray ionization (ESI) for mass spectrometric (MS) detection. Separation conditions using potassium phosphate buffer and ammonium formate buffer have been compared for analysis of eleven pharmaceutical bases. The results showed improvements in separation efficiency and peak symmetry when phosphate buffer was used. The low flow in CE may enable utilization of these advances with MS detection. Compared with ESI, the APPI technique provided a cluster-free background. The enhanced signal-to-noise ratio in the total ion current (TIC) and the reduced spectral background indicated that the APPI process is less affected by non-volatile salts in the CE buffers. This results in a wider range of choice of CE buffers in CE/MS analysis when APPI is the ionization method.

Differences in the uptake and nuclear localization of anti-proliferative heparan sulfate between human lung fibroblasts and human lung carcinoma cells

Heparan sulfate inhibits the proliferation of normal human lung fibroblasts (HFL-1) but not of a human lung carcinoma cell-line (A549). In this study we investigated possible mechanisms and structural requirements by which antiproliferative heparan sulfates exerts its effects on binding, uptake and subcellular localisation. Both HFL-1 and A549 cells were incubated with 125I- or rhodamine-labeled L-iduronate-rich antiproliferative heparan sulfate species as well as L-iduronate-poor inactive ones. The antiproliferative heparan sulfate was bound to the cell surface on both HFL-1 and A549 cells, but to a lesser extent and with less affinity to A549 cells. Both cell types bound the antiproliferative heparan sulfate with one high- and with one low affinity site. The L-iduronate-poor heparan sulfate bound to a lesser extent and with less affinity to both cell types compared to the antiproliferative heparan sulfate. The antiproliferative heparan sulfate accumulated in the cytoplasm of HFL-1 cells after 24 h incubation, but after 72 h it was found evenly distributed in the nucleus. The time-scale for antiproliferative activity correlated with nuclear localization. In contrast, in A549 cells it was only found near the nuclear membrane. The inactive heparan sulfate was taken up in considerably smaller amounts compared to the antiproliferative heparan sulfate and could not be detected in the nucleus of either HFL-1 or A549 cells. Our data suggest that the antiproliferative activity of L-iduronate-rich heparan sulfate on normal fibroblasts may be due to direct effects on nuclear processes, such as gene transcription.

An imaging system for monitoring receptive field dynamics

The paper describes a computerized method, termed receptive field imaging (RFI), for the rapid mapping of multiple receptive fields and their respective sensitivity distributions. RFI uses random stimulation of multiple sites, in combination with an averaging procedure, to extract the relative contribution from each of the stimulated sites. Automated multi-electrode stimulation and recording, with spike detection and counting, are performed on-line by the RFI programme. Direct user interpretation of receptive field changes is made possible by a user-friendly graphic interface. A series of imaging experiments was carried out to evaluate the functional capacity of the system. RFI was tested on the receptive fields in the nociceptive withdrawal reflex (NWR) system in the rat. RFI replicates the results obtained with conventional methods and allows the display of receptive field dynamics induced by topical spinal cord application of morphine and naloxone on a minute-to-minute time scale. Data variance was estimated, and proved to be small enough to yield a stable representation of the receptive field, thereby achieving a high sensitivity in dynamic imaging experiments. The large number of stimulation and registration sites that can be monitored in parallel permits detailed network analysis of synaptic sets, corresponding to 'connection weights' between individual neurones.

Protective role for proteoglycans against cationic lipid cytotoxicity allowing optimal transfection efficiency in vitro

A dependence on proteoglycans for cationic lipid-mediated gene transfer has been suggested in previous studies [Mislick and Baldeschwieler (1996) Proc. Natl. Acad. Sci. U.S.A. 93, 12349-12354; Mounkes, Zhong, Cipres-Palacin, Heath and Debs (1998) J. Biol. Chem. 273, 26164-26170]. We have evaluated the mechanism of proteoglycan involvement in cationic lipid-mediated gene transfer. DNA plasmid uptake and gene expression were studied in wild-type Chinese hamster ovary (CHO) cells (CHO-K1), heparan sulphate-deficient CHO cells (pgsD-677) and proteoglycan-deficient CHO cells (pgsB-618). At an optimal ratio of cationic lipid to DNA, a substantial decrease in reporter gene expression was observed in proteoglycan-deficient cells compared with that in heparan sulphate-deficient and wild-type cells. However, there were no differences in reporter gene expression between the cell lines when transfected by electroporation. Moreover, all cell lines exhibited equal cationic-lipid-DNA complex uptake activities, as assessed by the measurement of intracellular (32)P-labelled and rhodamine-labelled DNA plasmid. An analysis of reflected-light images of wild-type and proteoglycan-deficient cells suggested that cationic lipids were preferentially toxic to proteoglycan-deficient cells. Cell-growth assays confirmed this, showing that cationic lipids exhibited a greater anti-proliferative activity in proteoglycan-deficient cells and in chlorate-treated wild-type cells than in the other cell lines. The growth-inhibitory effect of cationic lipids was abrogated by the addition of exogenous sulphated glycosaminoglycans. We conclude that the glycosaminoglycan part of proteoglycans serves a protective role against cationic lipid cytotoxicity, allowing optimal transfection efficiency in vitro.

Intracellular accumulation of secreted proteoglycans inhibits cationic lipid-mediated gene transfer. Co-transfer of glycosaminoglycans to the nucleus

Molecules secreted by potential target cells may interfere with cationic lipid-mediated gene transfer. This has been studied using human lung fibroblasts and human epidermoid lung cancer cells. Secreted cell medium components caused a substantial decrease both in the uptake of cationic lipid-DNA complexes (2-4-fold) and in reporter gene expression (100-1000-fold). Metabolic labeling of the cell medium showed that especially [35S]sulfate-labeled macromolecules competed with DNA for binding to the cationic lipid. Release of DNA from the cationic lipid by cell medium components was demonstrated by an ethidium bromide intercalation assay. In the presence of the cationic lipid, the secreted macromolecules were internalized by the cells. By enzymatic digestions, it was shown that the competing macromolecules consist of chondroitin/dermatan sulfate and heparan sulfate proteoglycans and that the effects on transfection were mediated by the polyanionic glycosaminoglycan portion of the proteoglycan. Accordingly, pretreatment of cell medium with the polycationic peptide protamine sulfate abrogated the inhibitory effects on gene transfer. Fluorescence microscopy studies revealed that heparan sulfate, internalized as a complex with cationic lipids, accumulated in the cell nuclei. These results support the view that the lack of specificity of this type of gene transfer vehicle is a major hindrance to efficient and safe in vivo administration.