The Effect of Percutaneous Flexor Tenotomy on Healing and Prevention of Foot Ulcers in Patients With Claw Deformity of the Toe

Claw deformity of the foot is frequently seen in patients with diabetes mellitus. Percutaneous flexor tenotomy is a simple surgical procedure for the treatment of foot ulcers on the distal end of the toe caused by this deformity. This procedure can also be performed to prevent ulcers in claw toes that are at risk of ulceration. The aim of this study is to investigate whether percutaneous flexor tenotomy is an effective surgical method for treatment and prevention of toe ulcers in patients with claw deformity. This retrospective study, with a median follow-up of 13.4 (1 to 66.7) months, included all consecutive patients who underwent percutaneous flexor tenotomy in 2 hospitals between July 2012 and April 2017. In total, 101 feet underwent flexor tenotomy: 84 (83.3%) therapeutic and 17 (16.7%) prophylactic. Of the 84 therapeutic procedures, 95.1% healed, with a median healing time of 27 days. In 11 (13.3%) therapeutic procedures, a reulceration was recorded. In the therapeutic group, 4 (4.8%) infections and 1 (1.2%) amputation of the digit occurred. In the 17 prophylactic procedures, local bleeding was recorded in 1 (5.9%). In the prophylactic group, 2 ulcers occurred. In 77 (76.2%) of all procedures, patients had diabetes mellitus. In conclusion, percutaneous flexor tenotomy is an effective, safe, and minimally invasive procedure for the treatment and prevention of toe ulcers in patients with claw deformity.

Effects of TNT contaminated soil on vegetation at an explosive range by probing UPLC-qTOF MS profiling method

Three tree species (Wild olive, Stinkwood and Cape Holy) and a shrub (Dovyalis caffra) were each potted in 20 L pots in order to evaluate the effect of 1,3,5-trinitrotoluene (TNT)-contaminated soil on vegetation. TNT contamination was established by dissolving flake TNT in acetone at 300 and 600 mg per kilogram soil concentrations. One pot for every species was left uncontaminated as control elements. A set of 16 samples, four contaminated, four uncontaminated aerial parts and their corresponding soils, were gathered. These were processed and subjected to a solid phase extraction method to isolate analytes of interest. A laboratory analytical method was applied using ultra-performance liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (UPLC-qTOF MS). For the UPLC-qTOF MS a gradient for the mobile phase was found which allowed the profiling and separation of metabolites in the aerial parts of the vegetation. This method allowed identification and quantification of major changes caused by TNT contaminated soil on vegetation. The Synapt High Definition Mass Spectrometer SYNAPT HDMS G1 was operated using the electrospray ionisation (ESI) technique in both positive and negative mode. A clear comparison of profiles was achieved and this has been demonstrated by the distinct newly-formed metabolites in the TNT contaminated vegetation understudy. The results have also shown that the chlorophyll region in the contaminated profile was also affected by the uptake of TNT degradation products. This has been observed in the contaminated profiles of Wild olive, Stinkwood and Cape Holly extracts indicating enhanced nutrient availability.

[Standardization and modeling of surgical processes]

BACKGROUND

Due to the technological developments around the operating room, surgery in the twenty-first century is undergoing a paradigm shift.

OBJECTIVE

Which technologies have already been integrated into the surgical routine? How can a favorable cost-benefit balance be achieved by the implementation of new software-based assistance systems?

METHODS

This article presents the state of the art technology as exemplified by a semi-automated operation system for otorhinolaryngology surgery. The main focus is on systems for implementation of digital handbooks and navigational functions in situ.

RESULTS

On the basis of continuous development in digital imaging, decisions may by facilitated by individual patient models thus allowing procedures to be optimized. The ongoing digitization and linking of all relevant information enable a high level of standardization in terms of operating procedures. This may be used by assistance systems as a basis for complete documentation and high process reliability.

CONCLUSION

Automation of processes in the operating room results in an increase in quality, precision and standardization so that the effectiveness and efficiency of treatment can be improved; however, care must be taken that detrimental consequences, such as loss of skills and placing too much faith in technology must be avoided by adapted training concepts.

Are two retrograde 3.5 mm screws superior to one 7.3 mm screw for anterior pelvic ring fixation in bones with low bone mineral density?

Objectives

Osteosynthesis of anterior pubic ramus fractures using one large-diameter screw can be challenging in terms of both surgical procedure and fixation stability. Small-fragment screws have the advantage of following the pelvic cortex and being more flexible.

The aim of the present study was to biomechanically compare retrograde intramedullary fixation of the superior pubic ramus using either one large- or two small-diameter screws.

Materials and Methods

A total of 12 human cadaveric hemipelvises were analysed in a matched pair study design. Bone mineral density of the specimens was 68 mgHA/cm³ (standard deviation (sd) 52). The anterior pelvic ring fracture was fixed with either one 7.3 mm cannulated screw (Group 1) or two 3.5 mm pelvic cortex screws (Group 2). Progressively increasing cyclic axial loading was applied through the acetabulum. Relative movements in terms of interfragmentary displacement and gap angle at the fracture site were evaluated by means of optical movement tracking. The Wilcoxon signed-rank test was applied to identify significant differences between the groups

Results

Initial axial construct stiffness was not significantly different between the groups (p = 0.463). Interfragmentary displacement and gap angle at the fracture site were also not statistically significantly different between the groups throughout the evaluated cycles (p ⩾ 0.249). Similarly, cycles to failure were not statistically different between Group 1 (8438, sd 6968) and Group 2 (10 213, sd 10 334), p = 0.379. Failure mode in both groups was characterised by screw cutting through the cancellous bone.

Conclusion

From a biomechanical point of view, pubic ramus stabilisation with either one large or two small fragment screw osteosynthesis is comparable in osteoporotic bone. However, the two-screw fixation technique is less demanding as the smaller screws deflect at the cortical margins.

Cite this article: Y. P. Acklin, I. Zderic, S. Grechenig, R. G. Richards, P. Schmitz, B. Gueorguiev. Are two retrograde 3.5 mm screws superior to one 7.3 mm screw for anterior pelvic ring fixation in bones with low bone mineral density? Bone Joint Res 2017;6:8–13. DOI: 10.1302/2046-3758.61.BJR-2016-0261.

3D Navigo™ versus TRUS-guided prostate biopsy in prostate cancer detection

INTRODUCTION

To overcome the limitations regarding transrectal ultrasound (TRUS)-guided biopsies in prostate cancer (PCa) detection, there is a focus on new imaging technologies. The Navigo™ system (UC-care, Israel) uses regular TRUS images and electrospatial monitoring to generate a 3D model of the prostate. The aim of this study was to compare cancer detection rates between the Navigo™ system and conventional TRUS, in patients without a history of PCa.

METHODS

We performed a retrospective study by collecting data from all patients who underwent 12-core prostate biopsies from lateral peripheral zones between September 2013 and February 2015 at the Jeroen Bosch Hospital in 's-Hertogenbosch (Netherlands).

RESULTS

A total of 325 patients met our inclusion criteria. 77.8 % of biopsy sessions were performed using the Navigo™ system. There was no statistically significant difference in PCa detection (39.9 vs 46.2 % with Navigo™ system and TRUS, respectively). Using the Navigo™ system for taking prostate biopsies proved not to be associated with the presence of PCa at biopsy, likewise for clinically significant PCa and for both subgroups.

LIMITATIONS

The limitations of the study include its retrospective design, the limited number of patients in the conventional TRUS group, the statistically significant different number of biopsy sessions and the ones performed by an advanced physician in both groups.

CONCLUSION

In our study, there is no added value of 3D TRUS using Navigo™ system compared to conventional 2D TRUS regarding PCa detection in biopsy-naive men and men with prior negative biopsy.

The impact of flooding on people living with HIV: a case study from the Ohangwena Region, Namibia

BACKGROUND

Floods are a disaster situation for all affected populations and especially for vulnerable groups within communities such as children, orphans, women, and people with chronic diseases such as HIV and AIDS. They need functioning health care, sanitation and hygiene, safe water, and healthy food supply, and are critically dependent on their social care and support networks. A study carried out in the Ohangwena region, Namibia, where HIV prevalence is high and extensive flooding frequently occurs, aims to provide a deeper understanding of the impact that flooding has on people living with HIV (PLWHIV) as well as on HIV service providers in the region.

DESIGN

The qualitative research applying grounded theory included semi-structured interviews with PLWHIV, focus group discussions with HIV service providers, and a national feedback meeting. The findings were interpreted using the sustainable livelihoods framework, the natural hazard research approach, and health behaviour theories.

RESULTS

The study reveals that flooding poses major problems to PLWHIV in terms of their everyday lives, affecting livelihoods, work, income, and living conditions. The factors threatening them under normal conditions - poverty, malnutrition, unsafe water, sanitation and hygiene, limited access to health facilities, a weak health status, and stigma - are intensified by flood-related breakdown of infrastructure, insecurity, malnutrition, and diseases evolving over the course of a flood. A potential dual risk exists for their health: the increased risk both of infection and disease due to the inaccessibility of health services and antiretroviral treatment. A HIV and Flooding Framework was developed to display the results.

CONCLUSIONS

This study demonstrates that vulnerabilities and health risks of PLWHIV will increase in a disaster situation like flooding if access to HIV prevention, treatment, care and support are not addressed and ensured. The findings and the HIV and Flooding Framework are not specific to Ohangwena and can be transferred to any flood-affected region that has a high HIV prevalence and relies mainly on subsistence agriculture. They serve as a model case for analysing vulnerabilities related to health and health service provision under disaster conditions. The impact will vary according to the physical, geographical, climatological, social, and behavioural characteristics of the region and the people affected. In the Ohangwena region, a disaster risk management mechanism is already in place which addresses people with HIV during flooding. However, preparedness could be improved further by applying the HIV and Flooding Framework.

Small changes in bone structure of female α7 nicotinic acetylcholine receptor knockout mice

Background

Recently, analysis of bone from knockout mice identified muscarinic acetylcholine receptor subtype M3 (mAChR M3) and nicotinic acetylcholine receptor (nAChR) subunit α2 as positive regulator of bone mass accrual whereas of male mice deficient for α7-nAChR (α7KO) did not reveal impact in regulation of bone remodeling. Since female sex hormones are involved in fair coordination of osteoblast bone formation and osteoclast bone degradation we assigned the current study to analyze bone strength, composition and microarchitecture of female α7KO compared to their corresponding wild-type mice (α7WT).

Methods

Vertebrae and long bones of female 16-week-old α7KO (n = 10) and α7WT (n = 8) were extracted and analyzed by means of histological, radiological, biomechanical, cell- and molecular methods as well as time of flight secondary ion mass spectrometry (ToF-SIMS) and transmission electron microscopy (TEM).

Results

Bone of female α7KO revealed a significant increase in bending stiffness (p < 0.05) and cortical thickness (p < 0.05) compared to α7WT, whereas gene expression of osteoclast marker cathepsin K was declined. ToF-SIMS analysis detected a decrease in trabecular calcium content and an increase in C₄H₆N⁺ (p < 0.05) and C₄H₈N⁺ (p < 0.001) collagen fragments whereas a loss of osteoid was found by means of TEM.

Conclusions

Our results on female α7KO bone identified differences in bone strength and composition. In addition, we could demonstrate that α7-nAChRs are involved in regulation of bone remodelling. In contrast to mAChR M3 and nAChR subunit α2 the α7-nAChR favours reduction of bone strength thereby showing similar effects as α7β2-nAChR in male mice. nAChR are able to form heteropentameric receptors containing α- and β-subunits as well as the subunits α7 can be arranged as homopentameric cation channel. The different effects of homopentameric and heteropentameric α7-nAChR on bone need to be analysed in future studies as well as gender effects of cholinergic receptors on bone homeostasis.

Quantification of calcium content in bone by using ToF-SIMS--a first approach

The determination of the spatially resolved calcium distribution and concentration in bone is essential for the assessment of bone quality. It enables the diagnosis and elucidation of bone diseases, the course of bone remodelling and the assessment of bone quality at interfaces to implants. With time-of-flight secondary ion mass spectrometry (ToF-SIMS) the calcium distribution in bone cross sections is mapped semi-quantitatively with a lateral resolution of up to 1 μm. As standards for the calibration of the ToF-SIMS data calcium hydroxyapatite collagen scaffolds with different compositions were synthesized. The standards were characterised by loss of ignition, x-ray diffractometry (XRD) and x-ray photoelectron spectroscopy (XPS). The secondary ion count rate for calcium and the calcium content of the standards show a linear dependence. The obtained calibration curve is used for the quantification of the calcium content in the bone of rats. The calcium concentration within an animal model for osteoporosis induction is monitored. Exemplarily the calcium content of the bones was quantified by XPS for validation of the results. Furthermore a calcium mass image is compared with an XPS image to demonstrate the better lateral resolution of ToF-SIMS which advances the locally resolved quantification of the calcium content.

Cyr61 is a target for heparin in reducing MV3 melanoma cell adhesion and migration via the integrin VLA-4

The integrin VLA-4 is important for the metastatic dissemination of melanoma cells. We could recently show that heparin can block VLA-4 binding, which contributes, next to blocking P- and L-selectin, to the understanding of antimetastatic activities of heparin. The matricellular ligand Cyr61, secreted by numerous tumours, is responsible for increased tumourigenicity and metastasis. This has been attributed to Cyr61 binding to, and thus activating integrins. However, a VLA-4/Cyr61 axis has not yet been reported. Since Cyr61 possesses heparin binding capabilities, Cyr61 can be supposed as potential target for heparin to indirectly interfere with integrin functions. The present in vitro studies address (i) the existence of a Cyr61/VLA-4 axis and (ii) the functional relevance of heparin interference via Cyr61. The C-terminal module III of Cyr61 could be exposed as nanomolar affine binding site for VLA-4. A shRNA-based knockdown of Cyr61 in MV3 human melanoma cells reduced VLA-4-mediated cell binding to VCAM-1, migration on fibronectin, and integrin signalling functions significantly. Using a biosensor approach we provide insight into heparin interference with this process. The low-molecular-weight heparin tinzaparin, but not the pentasaccharide fondaparinux, binds module IV of Cyr61 with micromolar affinity. But tinzaparin cannot interfere with Cyr61 accumulation onto syndecan-4, indicating different Cyr61 binding sites for heparin and other GAGs. Nonetheless, tinzaparin affects the VLA-4 binding and signalling functions selectively via Cyr61 already at very low concentration most likely by blocking the cellular secreted free Cyr61. This study emphasises Cyr61 as promising, and hitherto not considered target for heparin to selectively influence integrin functions.

Comparison of tenocytes and mesenchymal stem cells seeded on biodegradable scaffolds in a full-size tendon defect model

In order to investigate cell-based tendon regeneration, a tendon rupture was simulated by utilizing a critical full-size model in female rat achilles tendons. For bridging the defect, polyglycol acid (PGA) and collagen type I scaffolds were used and fixed with a frame suture to ensure postoperatively a functional continuity. Scaffolds were seeded with mesenchymal stem cells (MSC) or tenocytes derived from male animals, while control groups were left without cells. After a healing period of 16 weeks, biomechanical, PCR, histologic, and electron microscopic analyses of the regenerates were performed. Genomic PCR for male-specific gene was used to detect transplanted cells in the regenerates. After 16 weeks, central ossification and tendon-like tissue in the superficial tendon layers were observed in all study groups. Biomechanical test showed that samples loaded with tenocytes had significantly better failure strength/cross-section ratio (P < 0.01) compared to MSC and the control groups whereas maximum failure strength was similar in all groups. Thus, we concluded that the application of tenocytes improves the outcome in this model concerning the grade of ossification and the mechanical properties in comparison to the use of MSC or just scaffold materials.

Orientation and detachment dynamics of Bacillus spores from stainless steel under controlled shear flow: modelling of the adhesion force

Shear-flow induced spore detachment was performed under well-controlled laminar flow conditions, in a specially-designed shear stress flow chamber. By comparing detachment profiles of a panel of four strains, belonging to the B. cereus group (B. cereus and B. thuringiensis) and to less related Bacillus species (B. pumilus), it was shown that the spore ability of attaching to stainless steel, probed under dynamic conditions, was mainly affected by the presence (and number) of appendages. Adhesion force between the B. cereus 98/4 strain and stainless steel was quantified at nanoscale. To this aim, detachment results were combined with a theoretical modelling, based on the balance of hydrodynamic forces and torque exerted over a simplified spore model with a spherical form. The wall shear stress, required to remove 50% of the spores initially attached to stainless steel, was determined. On this basis, an adhesion force of 930 ± 390 pN was obtained. Real-time re-orientation of B. cereus 98/4 spores was experimentally established, by using a high-speed camera for tracking the motions of individual spores with high temporal and spatial resolution. Even though tethered to stainless steel without any detachment occurring, spores kept mobile on the substratum, probably due to the existence of discrete bonds or local clusters of anchoring sites, and tended to re-orientate in the flow direction, for minimizing hydrodynamic forces and torque exerted by fluid flow. A significant heterogeneity within the population was also observed, with the co-existence of both moving and immobile spores.

Study of bioadhesion on a flat plate with a yeast/glass model system

The attachment of microorganisms to a surface is a critical first step of biofilm fouling in membrane processes. The shear-induced detachment of baker's yeast in adhesive contact with a plane glass surface was thus experimentally studied, using a specially designed shear stress flow chamber. The yeast was marketed either as rod-shaped pellets (type I yeast) or as spherical pellets (type II yeast). A complete series of experiments for measuring the shear stress necessary to detach a given proportion of individual yeast cells of type I or II was performed under different environmental conditions (ionic strength, contact time). In parallel, the surface physicochemical properties of the cells (surface charge, hydrophobicity, and electron donor and electron acceptor components) were determined. For the first type of yeast cells, which were rather hydrophilic, adhesion to the glass plate was weak. This was due to both electrostatic effects and hydrophilic repulsion. Furthermore, adhesion was not sensitive to any variation of the ionic strength. For yeast of the second type, adhesion was drastically increased. This could be explained by their physicochemical surface properties and especially their hydrophobic and electron acceptor components, which caused strong attractive van der Waals and Lewis acid-base interactions, counterbalancing the electrostatic repulsion. For increasing ionic strengths, adhesion was greater, due to lower electrostatic repulsion. The results were quantified through the definition of a critical wall shear stress ( tau w 50% ) required to detach 50% of the yeast cells initially deposited on the glass surface. The influence of the contact time was also evaluated and it was shown that, whatever the type of yeast, macromolecules such as proteins were released into the extracellular medium due to cell lysis and could contribute to the formation of a conditioning film. As a result, the cells were more strongly stuck to the glass plate.

Effects of beta-endorphin on nasal allergic inflammation

BACKGROUND

Beta-endorphin is a derivative of pro-opiomelanocortin. Cells of the immune system can also synthesize and secrete beta-endorphin. Its concentration is increased during the allergic reaction and during stress. Increased reactivity during psychological stress of allergic subjects is also well known.

OBJECTIVE

Is beta-endorphin one physiological link between stress and an exacerbation of the allergic reaction?

METHODS

First, intranasal beta-endorphin challenges with subsequent lavages to determine histamine and albumin levels and measurements of nasal flow and resistance in dose-response and time course experiments were performed. Secondly, we examined whether beta-endorphin pre-treatment increased the antigen-induced release of histamine and albumin in nasal lavages and the clinical symptoms.

RESULTS

Exogenous beta-endorphin (100 pM-10 microM/mL) induced a dose-dependent increase in nasal symptoms in asymptomatic allergic subjects with rhinitis (n = 14) as well as in non-allergic controls (n = 10), but did not release any mediators into nasal secretion. However, comparing the antigen-evoked release of mediators into nasal secretions with that of a beta-endorphin pre-treated antigen challenge we could note a significant enhancement of human serum albumin influx (P < 0.05) and histamine liberation (P < 0.05) 10 min after antigen challenge compared with the allergen challenge alone, with also a correlation with the more pronounced decrease in nasal flow (P < 0.05).

CONCLUSION

These results suggest that beta-endorphin-induced increase in nasal congestion is mediated through direct neuroendocrine receptor activation independent of mast cell activation and that during the allergic reaction there is a beta-endorphin/mast cell interaction that enhances the mediator response to nasal allergen challenge.

Evaluation of a target contouring protocol for 3D conformal radiotherapy in non-small cell lung cancer

BACKGROUND

A protocol for the contouring of target volumes in lung cancer was implemented. Subsequently, a study was performed in order to determine the intra and inter-clinician variations in contoured volumes.

MATERIALS AND METHODS

Six radiation oncologists (RO) contoured the gross tumour volume (GTV) and/or clinical target volume (CTV), and planning target volume (PTV) for three patients with non-small cell lung cancer (NSCLC), on two separate occasions. These were, respectively, a well-circumscribed T1N0M0 lesion, an irregularly shaped T2N0M0 lesion, and a T2N2M0 tumour. Detailed diagnostic radiology reports were provided and contours were entered into a 3D planning system. The target volumes were calculated and beams-eye view (BEV) plots were generated to visualise differences in contouring. A software tool was used to expand the GTV and CTV in three dimensions for an automatically derived PTV.

RESULTS

Significant inter-RO variations in contoured target volumes were observed for all patients, and these were greater than intra-RO differences. The ratio of the largest to smallest contoured volume ranged from 1.6 for the GTV in the T1N0 lesion, to 2.0 for the PTV in the T2N2 lesion. The BEV plots revealed significant inter-RO variations in contouring the mediastinal CTV. The PTV's derived using a 3D margin programme were larger than manually contoured PTV's. These variations did not correlate with the experience of ROs.

CONCLUSIONS

Despite the use of an institutional contouring protocol, significant interclinician variations persist in contouring target volumes in NSCLC. Additional measures to decrease such variations should be incorporated into clinical trials.

Isolated limb perfusion with tumour necrosis factor-alpha and melphalan with or without interferon-gamma for the treatment of in-transit melanoma metastases: a multicentre randomized phase II study

This open, multicentre, randomized phase II trial was conducted to determine the effect of isolated limb perfusion (ILP) with tumour necrosis factor-alpha (TNFalpha) in combination with melphalan with or without interferon-gamma (IFNgamma) in patients with in-transit metastases of melanoma of the limbs (MD Anderson stage IIIA or IIIAB, AJCC stage III). The 64 patients included were randomized to receive either a two- drug regimen consisting of TNFalpha and melphalan (TM-ILP) or a three-drug regimen consisting of TNFalpha, melphalan and INFgamma (TIM-ILP). Patients randomized to receive IFNgamma were pretreated for 2 days before the ILP with once daily 0.2 mg IFNgamma subcutaneously and also received the same amount of IFNgamma during ILP. A total of 47 complete responses (73%) were reported, 22 (69%) of which occurred in the TM-ILP group and 25 (78%) in the TIM-ILP group; the difference was not significant. The 14 partial responses (22%) were split evenly between the treatment groups. In the TM-ILP group, two cases of stable disease and one case of progressive disease were reported. The overall response rate (complete plus partial responses) was 100% in the TIM-ILP group and 91% in the TM-ILP group, yielding an overall response of 95% for this study. In the historical control data, where 103 patients had received melphalan alone (M-ILP), there were 54 records of complete responses (52%) and 80 of complete or partial responses (78%). The median survival time estimated by the Kaplan-Meier method was 819 days for the TM-ILP group, > 705 days for the TIM-ILP group and 873 days for the combined study population; estimates for time to local progression or recurrence were 327 days, in excess of 498 days and 405 days, respectively. The corresponding figure for the historical controls was 338 days. These data suggest that TNFalpha associated with melphalan may be superior to melphalan alone for ILP.

[Sclera fixation of posterior chamber lenses in vitrectomized eyes. Perfluorocarbon as an operative aid]

INTRODUCTION

Accurate positioning of transsclerally fixated intraocular lenses in vitrectomized eyes is difficult to achieve because of the lack of stability of the globe. External stabilization with a Flieringa device is widely used. Internal stabilization, however, with liquid perfluorocarbon seems to be more advantageous.

METHODS

Endostabilization with perfluorocarbon after pars plana vitrectomy prior to transscleral fixation of a posterior chamber lens was performed in 18 eyes. The intraocular lens floats on the surface of the perfluorocarbon. The level of the liquid can be adjusted to position the lens accurately. Transscleral fixation of the intraocular lens was followed by silicone oil injection in 4 eyes and by BSS injection in 14 eyes.

RESULTS AND CONCLUSIONS

Endostabilization of the globe with liquid perfluorocarbon serves as a diaphragm preventing hemorrhage into the vitreous cavity and sliding of the intraocular lens, thus permitting proper positioning. There were no complications either intraoperatively, or postoperatively. Perfluorocarbon is a considerable aid in facilitating the positioning of a transsclerally fixated intraocular lens.

Involvement of hippocampal cAMP/cAMP-dependent protein kinase signaling pathways in a late memory consolidation phase of aversively motivated learning in rats

cAMP/cAMP-dependent protein kinase (PKA) signaling pathway has been recently proposed to participate in both the late phase of long term potentiation in the hippocampus and in the late, protein synthesis-dependent phase of memory formation. Here we report that a late memory consolidation phase of an inhibitory avoidance learning is regulated by an hippocampal cAMP signaling pathway that is activated, at least in part, by D1/D5 receptors. Bilateral infusion of SKF 38393 (7.5 microg/side), a D1/D5 receptor agonist, into the CA1 region of the dorsal hippocampus, enhanced retention of a step-down inhibitory avoidance when given 3 or 6 h, but not immediately (0 h) or 9 h, after training. In contrast, full retrograde amnesia was obtained when SCH 23390 (0.5 microg/side), a D1/D5 receptor antagonist, was infused into the hippocampus 3 or 6 h after training. Intrahippocampal infusion of 8Br-cAMP (1.25 microg/side), or forskolin (0.5 microg/side), an activator of adenylyl cyclase, enhanced memory when given 3 or 6 h after training. KT5720 (0.5 microg/side), a specific inhibitor of PKA, hindered memory consolidation when given immediately or 3 or 6 h posttraining. Rats submitted to the avoidance task showed learning-specific increases in hippocampal 3H-SCH 23390 binding and in the endogenous levels of cAMP 3 and 6 h after training. In addition, PKA activity and P-CREB (phosphorylated form of cAMP responsive element binding protein) immunoreactivity increased in the hippocampus immediately and 3 and 6 h after training. Together, these findings suggest that the late phase of memory consolidation of an inhibitory avoidance is modulated cAMP/PKA signaling pathways in the hippocampus.

Burnout in psychiatric nursing: a meta-analysis of related variables

The purpose of this study was to describe the relative strengths of a number of variables on burnout among psychiatric nurses. A meta-analysis of correlations revealed that burnout was negatively associated with job satisfaction, staff support and involvement with the organization and positively associated with role conflict. The results of the meta-analysis were in line with results of other studies in which different populations were investigated. Therefore, the findings as such are not specific to psychiatric nurses. Based on the literature, three typical risk factors of burnout among psychiatric nurses were found: the patient group the nurse works with, such as patients who are aggressive and suicidal; the inequity in the exchange process between nurses and patients; and the unrealistic expectations of nurses of the patients' potential for rehabilitation.

Somatosensory evoked potentials modified by laser-induced lesions of the rat cortex

The effect of focal application of laser energy on the modification of somatosensory evoked potentials (SEPs) was studied in sensory cortical fields of the rat. This article describes the methodological set-up for recording of SEPs and for determining location and size of the laser-induced lesion. The results show that both the size of the lesion of the somatosensory cortex, and the suppression and time of recovery of cortical SEPs varied depending on the laser energy dose. It remains to be analyzed by further experiments if the recovery of SEPs is due to a transient dysfunction of the somatosensory cortex or if it reflects cortical plasticity.

[Disruption of the blood-aqueous barrier after implantation of sclera-fixed posterior chamber lenses. Early postoperative phase and long-term outcome]

The implantation of transsclerally sutured posterior chamber lenses (PCL) leads to greater trauma to the eye than endocapsular PCL implantation. Persistent breakdown of the blood-aqueous barrier might impair the postoperative long-term prognosis. Using laser-tyndallometry, we quantified the disorder of the barrier function during the early postoperative phase and in the long-term postoperative course for both surgical procedures. During the first 3 postoperative days, flare values were three times higher in the group with transsclerally sutured PCL than in the conventional PCL group. Cell counts after transscleral suture fixation (27.7 +/- 18.3/0.075 mm3) decreased slightly during the first 5 postoperative days. In contrast, the conventional PCL group regained the preoperative level (2.5 +/- 5.1) after 3 days. After 3 months, no significant differences in flare values and cell counts were seen between the two groups. After implantation of transsclerally sutured posterior chamber lenses, breakdown of the blood-aqueous barrier was initially more pronounced than in conventional PCL implantation. However, the barrier function was re-established equally in both groups in the long term. No signs of a persistent disorder of the barrier were found.

[Spontaneous pregnancy after laparoscopic salpingostomy and electrocoagulation of the ovarian surfaces in a patients with polycystic ovary syndrome]

We report a case of a 25 year-old woman with repeated ovarian stimulation and laparoscopy because of anovulatory and tubal infertility due to polycystic ovarian syndrome (PCOS), who then spontaneously conceived. The complex nature of the multivariate cause of sterility is discussed together with therapeutic possibilities both in terms of the case-history and the literature.

Hippocampal cGMP and cAMP are differentially involved in memory processing of inhibitory avoidance learning

Cyclic GMP (cGMP) and cyclic AMP (cAMP) have been proposed to participate in the early and late stages of long-term potentiation (LTP), respectively. Here we report on the effect of post-training intrahippocampal infusion of membrane-permeable analogues of these cyclic nucleotides on the consolidation of inhibitory avoidance learning in rats and on the effect of this task on hippocampal cGMP and cAMP levels. Bilateral intrahippocampal microinjection of 8 Br-cGMP (1.25 micrograms per side) enhanced retention test performance when given immediately (0 min), but not when given 180 min, after training. In marked contrast, intrahippocampal infusion of the same dose of 8 Br-cAMP facilitated memory consolidation when given 180 min, but not 0 min, after training. Rats submitted to an inhibitory avoidance task showed a significant increase in the amount of cGMP in the hippocampus at 0 and 30 min after training, and in the amount of cAMP 30 and 180 min after training. Taken together, these results indicate that cGMP-regulated processes in the hippocampus play an important role in the early stages of memory consolidation and that cAMP signalling pathways are involved in the late post-training memory processing of inhibitory avoidance learning.