Peripheral nerve regeneration in rats using nerve graft in a vein conduit pre-filled with platelet-rich fibrin (PRF)

Treatment of peripheral nerve injury is not always satisfactory. To improve results, specific adjuvant methods have been used, such as platelet-rich fibrin (PRF) and vein conduits. The goal of this study was to assess whether use of PRF and vein conduits after nerve suture improves nerve regeneration as measured by a functional score and histomorphometry analysis. Ten isogenic spontaneously hypertensive rats were randomly assigned to 4 experimental procedures: 1) Sham group (n = 10); 2) Nerve graft (NG) group (n = 10); 3) Nerve graft covered with a vein conduit (NGVC) (n = 10); and 4) Nerve graft covered with a vein conduit pre-filled with PRF (NGVCP) (n = 10). Nerve repair results were evaluated on: sciatic functional index (SFI) at 0, 30, 60 and 90 days; morphometric and morphologic analysis of the distal nerve; and histological analysis of Fluoro-Gold® stained motor neurons in the anterior horn of the spinal cord. Compared to the Sham control group, the NGVC and NGVCP groups exhibited lower SFI on all measures. The NGVC group showed improvement in SFI at day 90, which was significant compared to the NG group. Fiber and axon diameters were comparable in the NGVC and NGVCP groups, which were both significantly lower than in the Sham and NG groups. Significant improvement was expected with PRF, but in fact the release of factors from this substance was not as effective as hoped.

Primary or secondary wound healing of the pin sites after removal of the external fixator: A monocenter prospective randomized controlled trial

Objective

The aim of this monocentre randomized controlled trial was to compare primary wound closure using a single button suture to secondary wound healing of pin sites after removal of the external fixator.

Methods

This non-inferiority trial included all patients who were treated with an external fixator. The primary outcome was infection. Secondary outcomes included all other complications, time to wound healing (in weeks), patients most satisfactory pin site, Visual Analogue Scale (VAS) for pain and the Vancouver Scar Scale (VSS) measured at every 2, 6, 12, 24 and 52 weeks. The most proximal pin site was randomly allocated (1:1) to either primary closure or secondary wound healing, while the following pin sites were treated alternately. Physicians at follow-up were blinded to the closure technique.

Results

A total of 70 patient, providing 241 pin sites were included between 1st January 2019 and 1st March 2020. One-hundred-twenty-three pin sites were treated with primary closure and 118 with secondary wound healing. Median age was 55 (46–67), 44% was male and median duration of the external fixator was 6 days (4–8).There was no significant difference in pin site infections (2% in the primary closure group versus 0% in the secondary healing group). Wound healing was significantly faster in the primary closure group (median 2 vs. 6 weeks, p=0.013). Although not statistically significant, patients seemed more satisfied with the primary closed pin sites (55%). The Vancouver Scar scale showed no differences between groups.

Conclusion

Primary closure of external pin sites does not result in higher infection rate than secondary wound healing and pin sites healed significantly faster after primary closure. Primary closure, therefore, should be the preferred method.

The role of seagrass vegetation and local environmental conditions in shaping benthic bacterial and macroinvertebrate communities in a tropical coastal lagoon

We investigated the influence of seagrass canopies on the benthic biodiversity of bacteria and macroinvertebrates in a Red Sea tropical lagoon. Changes in abundance, number of taxa and assemblage structure were analyzed in response to seagrass densities (low, SLD; high, SHD; seagrasses with algae, SA), and compared with unvegetated sediments. Biological and environmental variables were examined in these four habitats (hereafter called treatments), both in the underlaying sediments and overlaying waters, at three randomly picked locations in March 2017. Differences between treatments were more apparent in the benthic habitat than in the overlaying waters. The presence of vegetation (more than its cover) and changes in sedimentary features (grain size and metals) at local scales influenced the observed biological patterns, particularly for macroinvertebrates. Of note, the highest percentage of exclusive macroinvertebrate taxa (18% of the gamma diversity) was observed in the SHD treatment peaking in the SA for bacteria. Benthic macroinvertebrates and bacteria shared a generally low number of taxa across treatments and locations; approximately, 25% of the gamma diversity was shared among all treatments and locations for macrofauna, dropping to 11% for bacteria. Given the low overlap in the species distribution across the lagoon, sustaining the connectivity among heterogeneous soft sediment habitats appears to be essential for maintaining regional biodiversity. This study addresses a current scientific gap related to the relative contributions of vegetated and unvegetated habitats to biodiversity in tropical regions.

Progressive secondary exo-focal dopaminergic neurodegeneration occurs in not directly connected midbrain nuclei after pure motor-cortical stroke

Transsynaptic anterograde and retrograde degeneration of neurons and neural fibers are assumed to trigger local excitotoxicity and inflammatory processes. These processes in turn are thought to drive exo-focal neurodegeneration in remote areas connected to the infarcted tissue after ischemic stroke. In the case of middle cerebral artery occlusion (MCAO), in which striato-nigral connections are affected, the hypothesis of inflammation-induced remote neurodegeneration is based on the temporal dynamics of an early appearance of inflammatory markers in midbrain followed by dopaminergic neuronal loss. To test the hypothesis of a direct transsynaptic mediation of secondary exo-focal post-ischemic neurodegeneration, we used a photochemical induction of a stroke (PTS) in Sprague-Dawley rats restricted to motor cortex (MC), thereby sparing the striatal connections to dopaminergic midbrain nuclei. To dissect the temporal dynamics of post-ischemic neurodegeneration, we analyzed brain sections harvested at day 7 and 14 post stroke. Here, an unexpectedly pronounced and widespread loss of dopaminergic neurons occurred 14 days after stroke also affecting dopaminergic nuclei that are not directly coupled to MC. Since the pattern of neurodegeneration in case of a pure motor stroke is similar to a major stroke including the striatum, it is unlikely that direct synaptic coupling is a prerequisite for delayed secondary exo-focal post ischemic neurodegeneration. Furthermore, dopaminergic neurodegeneration was already detected by Fluoro-Jade C staining at day 7, coinciding with a solely slight inflammatory response. Thus, inflammation cannot be assumed to be the primary driver of exo-focal post-ischemic cell death. Moreover, nigral substance P (SP) expression indicated intact striato-nigral innervation after PTS, whereas opposing effects on SP expression after striatal infarcts argue against a critical role of SP in neurodegenerative or inflammatory processes during exo-focal neurodegeneration.

Coral reef degradation affects the potential for reef recovery after disturbance

The loss of coral cover is often accompanied by an increase of benthic algae, a decline in biodiversity and habitat complexity. However, it remains unclear how surrounding communities influence the trajectories of re-colonization between pulse disturbance events. Over a 12-month field experiment in the central Red Sea, we examined how healthy (hard-coral dominated) and degraded (algae-dominated) reef areas influence recruitment and succession patterns of benthic reef foundation communities on bare substrates. Crustose coralline algae and other calcifiers were important colonizers in the healthy reef area, promoting the accumulation of inorganic carbon. Contrary, substrates in the degraded area were predominantly colonized by turf algae, lowering the accumulation of inorganic carbon by 178%. While coral larvae settlement similarly occurred in both habitats, degraded areas showed 50% fewer recruits. Our findings suggest that in degraded reefs the replenishment of adult coral populations is reduced due to recruitment inhibition through limited habitat complexity and grazing pressure, thereby restraining reef recovery.

Transverse resonance island buckets for synchrotron-radiation based electron time-of-flight spectroscopy

At the Metrology Light Source (MLS), the compact electron storage ring of the Physikalisch-Technische Bundesanstalt (PTB) with a circumference of 48 m, a specific operation mode with two stable closed orbits for stored electrons was realized by transverse resonance island buckets. One of these orbits is closing only after three turns. In combination with single-bunch operation, the new mode was applied for electron time-of-flight spectroscopy with an interval of the synchrotron radiation pulses which is three times the revolution period at the MLS of 160 ns. The achievement is of significant importance for PTB's future programs of angular-resolved electron spectroscopy with synchrotron radiation and similar projects at other compact electron storage rings. The scheme applied here for selecting the photons originating from a particular orbit by optical imaging has been used before in fs slicing applications and may be relevant for the BESSY VSR project of the Helmholtz-Zentrum Berlin.

DALYs, dollars and dogs: how best to analyse the economics of controlling zoonoses

Decision-makers increasingly require comprehensive economic metrics summarising and comparing the benefits and costs of controlling zoonotic diseases. The impact of disease in people is conventionally quantified in non-monetary terms, usually a disability-adjusted life year (DALY), whereas the losses due to disease in animals, particularly livestock, are quantified in monetary terms. The potential for the development of a non-monetary metric for ill health in animals, based on life years lost and disability, is discussed and rejected. Within and across animal species and livestock production systems, maximising life spans is not a consistent goal and morbidity/disabilities have very different weights and often lead to culling. By relating livestock losses to a measure of national income forgone, the recently developed alternative of converting monetary losses due to livestock illness into an animal loss equivalent (ALE) provides a viable solution. Based on this, the literature on the economics of controlling zoonoses is revisited and four options for quantifying and comparing benefits and costs are examined and illustrated using numerical examples. These are i) the simplistic grouping of all monetary elements and their comparison to DALYs averted (described as the aggregate net cost method), ii) the separable costs method, iii) the use of ALEs to convert all benefits to a non-monetary equivalent, termed the zoonotic DALY (zDALY), or iv) the use of a full monetary cost-benefit analysis, based on converting DALYs to a monetary equivalent. The strengths and weaknesses of each are discussed. For effective prioritisation and decision-making, it is vital that an analytical approach is widely adopted which yields consistent results and which supports the control of zoonoses.

Impacts of a high-discharge submarine sewage outfall on water quality in the coastal zone of Salvador (Bahia, Brazil)

Carbon and nitrogen stable isotopic signatures of suspended particulate organic matter and seawater biological oxygen demand (BOD) were measured along a coastal transect during summer 2015 to investigate pollution impacts of a high-discharge submarine sewage outfall close to Salvador, Brazil. Impacts of untreated sewage discharge were evident at the outfall site by depleted δ(13)Corg and δ(15)N signatures and 4-fold increased BOD rates. Pollution effects of a sewage plume were detectable for more than 6km downstream from the outfall site, as seasonal wind- and tide-driven shelf hydrodynamics facilitated its advective transport into near-shore waters. There, sewage pollution was detectable at recreational beaches by depleted stable isotope signatures and elevated BOD rates at high tides, suggesting high bacterial activity and increased infection risk by human pathogens. These findings indicate the urgent necessity for appropriate wastewater treatment in Salvador to achieve acceptable standards for released effluents and coastal zone water quality.

One for all: cobalt-containing polymethacrylates for magnetic ceramics, block copolymerization, unexpected electrochemistry, and stimuli-responsiveness

Functional cobalt-containing homo and block polymers are probed with respect to their redox-induced switchability and as preceramic materials.

High-energy anomaly in the angle-resolved photoemission spectra of Nd(2-x)Ce(x)CuO₄: evidence for a matrix element effect

We use polarization-dependent angle-resolved photoemission spectroscopy (ARPES) to study the high-energy anomaly (HEA) in the dispersion of Nd(2-x)Ce(x)CuO₄, x=0.123. We find that at particular photon energies the anomalous, waterfall-like dispersion gives way to a broad, continuous band. This suggests that the HEA is a matrix element effect: it arises due to a suppression of the intensity of the broadened quasiparticle band in a narrow momentum range. We confirm this interpretation experimentally, by showing that the HEA appears when the matrix element is suppressed deliberately by changing the light polarization. Calculations of the matrix element using atomic wave functions and simulation of the ARPES intensity with one-step model calculations provide further evidence for this scenario. The possibility to detect the full quasiparticle dispersion further allows us to extract the high-energy self-energy function near the center and at the edge of the Brillouin zone.

X-ray photoemission study of CeTIn(5) (T = Co, Rh, Ir)

We investigated CeTIn5 (T = Co, Rh, Ir) using temperature- and angle-dependent x-ray photoemission spectroscopy. The Ce 3d core level has a very similar shape for all three materials and is indicative of weak f-hybridization. The spectra were analyzed using a simplified version of the Anderson impurity model, which yields a Ce 4f occupancy that is larger than 0.9. The temperature dependence shows a continuous, irreversible and exclusive broadening of the Ce 3d peaks, due to oxidation of Ce at the surface.

Probing the complex ion structure in liquid carbon at 100 GPa

We present the first direct experimental test of the complex ion structure in liquid carbon at pressures around 100 GPa, using spectrally resolved x-ray scattering from shock-compressed graphite samples. Our results confirm the structure predicted by ab initio quantum simulations and demonstrate the importance of chemical bonds at extreme conditions similar to those found in the interiors of giant planets. The evidence presented here thus provides a firmer ground for modeling the evolution and current structure of carbon-bearing icy giants like Neptune, Uranus, and a number of extrasolar planets.

Persistence of brucellosis in pastoral systems

Regarded as a highly contagious, zoonotic disease with worldwide distribution, brucellosis is endemic in many countries and settings and is responsible for a considerable economic and health-related burden. Limited information is available on the persistence and prevalence of brucellosis in pastoral communities, due to the difficulty in gathering information and to their mobility. However, since these communities are economically and culturally dependent on livestock, it is important to further determine the cause of persistent disease and develop possible methods for its management. The two main objectives of this paper are to review the literature, identifying various epidemiological and social factors that affect the persistence of brucellosis in pastoral ecosystems, and determine prevalence estimates within these communities. The general trend of the summarised studies indicates low-level, relatively stable transmission of brucellosis in pastoral areas, when compared to transmission in intensive and semi-intensive peri-urban production systems. A formal mathematical analysis can be undertaken using matrix models or coupled differential equations. This allows an examination of the various conditions under which the number of diseased, infected or exposed animals remains stable. The authors examined an existing mathematical differential equation model for brucellosis in Mongolia for its equilibrium conditions and found it reasonably robust, though clearly more data are needed to estimate threshold densities for brucellosis transmission in other regions of the world. However, the results indicate the importance of livestock demographic determinants for brucellosis persistence. The paper concludes that brucellosis remains largely persistent in pastoral areas of the world, despite (varying) control efforts. Plans to control brucellosis in pastoral settings should include ecological considerations, such as sustaining ecosystem services in pastoral areas. This approach would include placing limitations on livestock stocking density, land reform, improved governance and integrated social and economic development.

[Transmission dynamics and cost-effectiveness of rabies control in dogs and humans in an African city]

Control of human rabies in developing countries depends on prevention in dogs. The purpose of this study was to evaluate the cost-saving potential for the public health sector of intervention to control rabies in animal-host reservoirs. An existing deterministic model was adapted to allow study of dog-to-human rabies transmission. Model parameters were fitted to data from routine weekly reports on the number of rabid dogs and human rabies exposures in N'Djamena, Chad. At the onset of study, the estimated effective reproductive ratio (Re) was 1.01 indicating stable low-level endemic rabies transmission. Simulations were performed to determine what effects mass vaccination and culling of dogs would have on the incidence of human rabies. Findings showed that a mass campaign allowing single parenteral vaccination of at least 70% of the canine population would be sufficient to interrupt transmission of rabies to humans for at least 6 years. The cost-effectiveness of mass dog vaccination was compared to that of "postexposure prophylaxis" (PEP) which would not reduce future human exposure. Results showed that a sustained 5-year PEP program together with a dog-vaccination campaign would be as cost-effective as PEP alone. Beyond a time-frame of 7 years, combining parenteral dog vaccination campaigns with human PEP appeared to be more cost-effective than human PEP alone.

[Fetoscopic laser coagulation in 100 consecutive monochorionic pregnancies with severe twin-to-twin transfusion syndrome]

OBJECTIVES

To report pre- and post-surgical datas of large series of severe twin-to-twin transfusion syndrome (TTTS) managed with laser ablation surgery in our centre, to evaluate the incidence of complications, perinatal outcome and to compare with other cohorts.

PATIENTS AND METHODS

Observational study of 100 cases of TTTS consecutively treated with fetoscopic laser coagulation between January 2004 and April 2010 in CMCO-SIHCUS of Schiltigheim.

RESULTS

There are nine stage I, 49 stage II, 38 stage III and four stage 4. Median gestation at time of laser is 20.6 weeks (14-29) whereas median gestation at delivery is 32.6 weeks (16.3-39). Overall perinatal survival rate is 68.5% (137 children over 200). Eighty-five percent have one or more surviving twins. The survival rate is the same for donors and for recipients. Preterm premature rupture of the membranes are observed in 17% of cases and the median gestational age for this complication is 30 weeks (20-34). Cerebral abnormalities are present in 7% of newborns.

CONCLUSION

Our results for the management of severe TTTS are comparable to the other reported series. There are still many questions remaining concerning the optimal management of TTTS.

Lower limits of fluorescein and indocyanine green dye for digital cSLO fluorescence angiography

BACKGROUND

With the advent of digital confocal scanning laser ophthalmoscopy it is possible to detect low levels of fluorescence. Here we used a novel confocal scanning laser ophthalmoscope (cSLO) to determine lower limits of dye required for fluorescein (FL) and indocyanine green (ICG) angiography.

METHODS

A cSLO (Heidelberg retina angiograph 2, Heidelberg Engineering, Dossenheim, Germany) with an optically pumped solid state laser (488 nm) for FL and a diode laser (790 nm) for ICG angiography (FL/ICG-A) was used. 62 FL-As were performed in 53 patients and 45 ICG-As were performed in 39 patients with neovascular age related macular degeneration. The volume and overall dye content of bolus injections was gradually tapered (FL: 500 mg, 250 mg, 200 mg, 166 mg, 100 mg; ICG: 25 mg, 20 mg, 15 mg, 10 mg, 5 mg, 2.5 mg), while dye concentrations were kept constant at 100 mg/ml for FL and at 5 mg/ml for ICG. Images were obtained 1, 5, 15, and 30 minutes after dye injection. Image quality was evaluated by two independent readers using standardised criteria.

RESULTS

For amounts down to 166 mg for FL and to 5 mg for ICG, sufficient image quality was achieved during all phases following injection. Only late phase images showed less contrast compared to typically used dye amounts, which was irrelevant for interpretation and clinical management.

CONCLUSIONS

With the increased sensitivity of this novel cSLO system, amounts of injected dye during FL-A can be reduced to one third for FL and to one fifth for ICG without relevant loss of image quality or information compared to conventionally used dye levels. These amounts can be used for routine angiography and allow relevant savings for units performing FL-A.

A model of animal-human brucellosis transmission in Mongolia

We developed a dynamic model of livestock-to-human brucellosis transmission in Mongolia. The compartmental model considers transmission within sheep and cattle populations and the transmission to humans as additive components. The model was fitted to demographic and seroprevalence data (Rose Bengal test) from livestock and annually reported new human brucellosis cases in Mongolia for 1991-1999 prior to the onset of a mass livestock-vaccination campaign (S19 Brucella abortus for cattle and Rev 1 Brucella melitensis for sheep and goat). The vaccination effect was fitted to livestock- and human-brucellosis data from the first 3 years of the vaccination campaign (2000-2002). Parameters were optimized on the basis of the goodness-of-fit (assessed by the deviance). The simultaneously fitted sheep-human and cattle-human contact rates show that 90% of human brucellosis was small-ruminant derived. Average effective reproductive ratios for the year 1999 were 1.2 for sheep and 1.7 for cattle.

cSLO-Fundusautofluoreszenz-Imaging

BACKGROUND

Fundus autofluorescence (FAF) originates from age- and disease-dependent accumulation of lipofuscin in the lysosomal compartment of the retinal pigment epithelium (RPE). FAF imaging is a noninvasive method to detect intrinsic RPE fluorescence in vivo. We describe features of a novel confocal scanning laser ophthalmoscope (cSLO) for FAF imaging and compare images to the previous cSLO system.

METHODS

FAF images were obtained with a cSLO using an optically pumped solid state laser (OPSL) instead of an argon laser for generation of excitation light at 488 nm. For detection of emitted FAF signals >500 nm a barrier filter was used.

RESULTS

The novel cSLO allows FAF imaging with a resolution of up to 5 microm/pixel to delineate normal and pathological features in various retinal pathologies including early-stage and advanced atrophic or neovascular age-related macular degeneration, macular edema, and retinal dystrophies. Further technical improvements include an internal fixation target and an enlarged optical focus adaption range.

CONCLUSIONS

Improved image quality using the novel cSLO for FAF imaging is of clinical relevance for diagnosis and precise phenotyping of retinal diseases. This method may also be useful to monitor therapeutic effects targeting RPE lipofuscin accumulation as a common pathogenetic pathway in various degenerative and hereditary retinal diseases.

[OCT in age-related macular degeneration. Findings, usage in clinical routine, and assessment of treatment outcome]

Optical coherence tomography (OCT) represents a fast and noninvasive examination technique that generates two-dimensional sections of the posterior pole in vivo. Although this method is now widely applied in the diagnosis of various heterogeneous macular diseases, its role in patients with age-related macular degeneration (AMD) is less well established. OCT allows for quantitative as well as qualitative assessment of various AMD phenotypes. Qualitative assessment comprises the evaluation of intra- or subretinal fluid, intraretinal cystoid spaces, and retinal pigment epithelial detachments. However, together with the clinical findings and fluorescence angiography, it can provide useful additional information including monitoring of treatment effects.

Transplantation von retinalem Pigmentepithel (RPE) nach CNV-Exzision bei altersabhängiger Makuladegeneration

Neovascular age-related macular degeneration (AMD) has become the leading cause for severe visual loss in all industrialized nations. Surgical excision of choroidal neovascularizations (CNV) is technically feasible but invariably associated with inadvertent removal of corresponding retinal pigment epithelium (RPE) and subsequent atrophy of the choriocapillaris, with the latter two layers being a prerequisite for normal photoreceptor function. To cover the RPE defect both heterologous and homologous RPE cell suspensions have been injected into the subretinal space. The lack of functional improvement has been attributed to various factors including RPE cell dedifferentiation, failure of adherence to Bruch's membrane as well as development of a regular RPE cell monolayer. Therefore, techniques for translocating intact autologous RPE cell sheets have been sought and preservation of foveal neurosensory functions has recently been successfully demonstrated. Besides translocation of a full-thickness RPE/Bruch's membrane/choroid patch outside the macular area, superfluous choroidal tissue may be ablated intraocularly using an excimer laser prior to translocation. Besides recent pharmacological approaches including anti-VEGF agents, these surgical developments open new perspectives for patients with neovascular AMD.

Palmare winkelstabile Plattenosteosynthese der instabilen distalen Radiusfraktur

Internal fixation of distal radius fractures often shows the problem of secondary dislocation due to dorsal comminution and osteoporosis. Although dorsal plating systems provide good stabilization, the intraoperative control of reduction is difficult in the comminuted area with high incidence for the need of cancellous bone graft. Occurrence of extensor tendon complications including tendonitis and rupture is not uncommon. The use of fixed angle devices by a palmar approach has demonstrated the advantage of better visualization and control at the fracture side. The subchondrale support of the articular surface by fixed angle pegs or screws prevents secondary dislocation allowing early mobilization. Better soft tissue coverage is associated with a low complication rate. 62 patients (average age 55 years) were treated with different fixed angel devices according to the fracture type and underwent retrospective evaluation with mean follow-up of 11 months (6-23 months). According to the AO Classification there were 3 A2, 24 A3, 7 B3, 14 C1, 9 C2 und 5 C3 fractures. The majority beside the B3 types and one C3 fracture were dorsally displaced. All of them showed healing without relevant secondary loss of reduction. Mean DASH score reached 19 points.

Accuracy of staging in early oesophageal cancer using high resolution endoscopy and high resolution endosonography: a comparative, prospective, and blinded trial

BACKGROUND AND AIMS

The increasing use of endoscopic resection for curative treatment of early oesophageal cancers requires accurate staging before therapy. In a prospective blinded trial, we compared staging of early oesophageal carcinoma using high resolution endoscopy (HR-E) with staging using high resolution endosonography (HR-EUS).

PATIENTS AND METHODS

A total of 100 patients (89 men, 11 women; mean age 63.9 (10.8) years (range 31-91)) with a suspicion of early oesophageal adenocarcinoma (n = 81) or squamous cell carcinoma (n = 19) were enrolled in the study. After endoscopic staging with high resolution video endoscopy by two experienced endoscopists, HR-EUS was performed by an experienced endosonographer who was blinded to the endoscopic assessment. Results of the staging examinations were correlated with the histology of the resected tumours.

RESULTS

Overall rates for accuracy of the endoscopic and endosonographic staging were 83.4% and 79.6%, respectively. Sensitivity for mucosal tumours (n = 68) was more than 90% (EUS 91.2%, endoscopy 94.1%) while sensitivity for submucosal tumours (n = 25) was lower, at 48% for EUS and 56% for endoscopic staging. A combination of the two techniques increased the sensitivity for submucosal tumours to 60%. Submucosal tumours in the tubular oesophagus were significantly better staged with HR-EUS than submucosal tumours close to the oesophagogastric junction (10/11 v 2/14; p<0.001). Tumours infiltrating the second and third submucosal layers were also more correctly diagnosed than tumours with slight infiltration of the first submucosal layer (sm1).

CONCLUSIONS

The overall diagnostic accuracy of both HR-E and HR-EUS with a 20 MHz miniprobe in early oesophageal cancer was high (approximately 80%), with no significant differences between the two techniques. HR-E and HR-EUS provide a high level of diagnostic accuracy for mucosal tumours and submucosal tumours located in the tubular part of the oesophagus. With submucosal tumours located at the oesophagogastric junction or with infiltration of the first third of the submucosa however, the diagnostic accuracy of both techniques is not yet satisfactory.

The utility of transesophageal echocardiography in determining the source of arterial embolization

Arterial embolism is frequently of a cardiac source. Arterial-arterial and paradoxical embolization also occurs. Failure to identify the origin may subject the patient to an important series of events. Herein we describe seven cases in which transesophageal echocardiography (TEE) was uniquely valuable in identifying the source or mechanism and in which conventional echocardiography and aortography were nondiagnostic. We conducted a chart review of patients with arterial emboli definitively diagnosed after undergoing TEE. Seven patients (mean age 68 years) were included in the study. Peripheral embolization occurred in four patients, visceral embolization occurred in one, and two experienced cerebrovascular events. Five patients had transthoracic echocardiography and six had aortography; none of these identified the source of embolization. All were diagnosed by TEE. Mobile aortic thrombus was the primary source in three patients, paradoxical embolization occurred in two, and two others had a combination of findings. Two patients received operative management with one mortality, and five received nonoperative management. The source of arterial emboli remains obscure in some patients. TEE can be valuable in identifying sources or mechanisms of embolization when angiography and conventional echocardiography are negative.

Potent antiretroviral treatment of HIV-infection results in suppression of the seminal shedding of HIV. The Swiss HIV Cohort Study

OBJECTIVE

The amount of HIV in semen likely influences infectiousness. Antiretroviral therapy decreases HIV-RNA in semen, but data on HIV concentrations in semen in a large cohort of men with suppressed HIV-RNA in blood is unavailable.

METHODS

Male patients with a treatment-induced reduction of HIV-RNA load in plasma below 400 copies/ml were asked to donate a semen and blood sample. Blood and seminal plasma were tested for the presence of HIV-RNA by the NucliSens method (detection limit 400 copies/ml). Seminal cell samples from 67 patients were further analysed for the presence of HIV-DNA using a nested DNA-polymerase chain reaction. Results of RNA and DNA testing in semen were compared with 55 HIV-positive antiretroviral therapy-naive men.

RESULTS

A total of 114 patients participated in the study. Seminal plasma HIV-RNA was detectable in only two patients [1.8%, 95% confidence ratio (CI), 0-4.2%] compared with a detection frequency of 67% in untreated controls [Odds ratio (OR), 0.01; 95% CI, 0-0.03]. Detection of cell-associated HIV-DNA in semen was significantly less frequent (16 versus 38%) in patients receiving suppressive therapy compared with untreated controls (OR, 0.32; 95% CI, 0.12-0.80).

CONCLUSION

In patients with treatment-induced suppression of blood viral load the likelihood of having detectable HIV in semen is very low (< 4%). In addition, seminal shedding of cell-free and cell-associated HIV is significantly lower than in an untreated population of HIV-infected asymptomatic men. On a population basis, this effect of therapy may help to reduce sexual transmission of HIV. However, individual patients may still be infected as evidenced by continued shedding of cells harbouring the HIV provirus.

[Cell cultures as a system for distinguishing between strains ofClostridium chauvoei and Clostridium septicum isolated in northeastern Mexico]

Clostridium chauvoei and C. septicum have similar characteristics as far as results from biochemical methods and gas chromatography (GC) are concerned. A total of 267 samples collected from sick or dead animals in the fields from Northeast Mexico, were bacteriologically analysed and differentiated by the GC technique. From these strains, 16 belong to the group of C. chauvoei/C. septicum. Studies on the effect of toxin on cell cultures of the lines EBL, 3T3, BHK21-BSR/PK5/88, CHO-K1 and MDCK were performed. The objective was to obtain further data for identification, as the results from GC do not allow exact differentiation between C. chauvoei and C. septicum species. The results were obtained in tests with BHK21-BSR/PK5/88 cells as this had proved to be the most sensitive cell line, closely followed by 3T3 and CHO-K1 cells. MDCK cells were of little sensitivity. Results of the cytotoxin test of the 16 strains were reproducible and suggested a differentiation between C. chauvoei and C. septicum other than indicated by GC. The cytotoxin test is a highly specific system that provides also an additional method to distinguish between C. chauvoei and C. septicum strains.

Detection of neutralizing antibodies against alpha-toxin of different Clostridium septicum strains in cell culture

Clostridium septicum, a ubiquitious organism, is the pathogen which causes the classical malignant edema after injuries. Because of its strong cytotoxic alpha-toxin, infections are often lethal. To prevent losses in animals, vaccination with alpha-toxoid vaccines is carried out. Quality control of the vaccines is done by a neutralization test in mice. A cytotoxin test and as an alternative method to detect neutralizing antibodies, a cytotoxin inhibition test was standardized. In the studies, alpha-toxin of the C. septicum reference strain (NC 547) from the National Collection of Type Cultures was compared with alpha-toxin of a field strain from an outbreak in Germany. Sera from five heterologous polyvalent and three monovalent vaccines from eight rabbit groups were available. Each vaccination had been carried out according to the procedure of the German Pharmacopoeia. In three out of the five sera of the groups vaccinated with the heterologous polyvalent vaccine, cytotoxin neutralizing antibodies were detected. High antibody titers were observed in sera of rabbits vaccinated with a vaccine of strain NC 547, lower titers in the sera of rabbits vaccinated with a vaccine of the field strain. No cytotoxin neutralizing antibodies could be found in the sera of rabbits vaccinated with the monovalent C. chauvoei vaccine. The toxins of all strains showed the same ranking of the vaccines. Vaccines which caused high antibody titers in the animals were detected by all toxins as such, as well as vaccines which had medium or low antibody inducing capacity. The results were independent of the C. septicum strain used for the production of alpha-toxin.

The control of haemorrhage at the operative site during periradicular surgery

CLINICAL TECHNIQUE: Effective apical sealing in endodontic surgery requires a dry root-end cavity to insert the filling material. A number of procedures for controlling haemorrhage have been described in the literature. An improvement of these techniques is proposed in this paper: by using a mixture of surgical wax and fibres of calcium alginate. This device, easy to place, sterile and non-toxic, permits placement of a root-end filling under more favourable conditions.

A new multiantigen immunoassay for the quantification of IgG antibodies to capsular polysaccharides of Streptococcus pneumoniae

A new nitrocellulose-based solid-phase multiantigen immunoassay (MAIA) for the detection of serum antibodies to Streptococcus pneumoniae capsular polysaccharides (PPSs) is presented. Evaluation with human sera showed that the MAIA test is reproducible, sensitive, and specific. It correlated well with a conventional ELISA method. The multiantigen strip system allowed quantification of antibodies against several PPS serotypes simultaneously and with a minimal amount of serum specimen. The presented solid-phase immunoassay for the quantification of anti-PPS antibodies seems to be a superior and attractive alternative to currently used ELISA tests and offers possibilities for standardization.

Surgical treatment of a periradicular lesion on an invaginated maxillary lateral incisor (dens in dente)

The complex anatomy of invaginated teeth make their root canal treatment difficult. Moreover, this treatment may compromise the future of the tooth if it is destined to support a post-retained coronal restoration. This case reports the successful surgical root canal treatment of an invaginated tooth using a retrograde filling with gutta-percha. After surgical exposure of the root-end and cleaning of the root canal, the gutta-percha was compacted in the root canal which had been coated previously with a zinc oxide-eugenol cement. The gutta-percha was then cold-burnished. Periapical radiographic examination after 1, 2, 3, 6 and 12 months showed periapical healing with osseous formation. This procedure, resulting in minimal loss of hard tissues, permitted subsequent restoration of the tooth.

Environment, incidence, aetiology, epizootiology and immunoprophylaxis of soil-borne diseases in north-east Mexico

Within the framework of an extensive research programme, the socio-economic and environmental conditions which influence the emergence of soil-borne diseases in north-eastern Mexico were analysed. Furthermore, specimens collected from carcasses in the field were bacteriologically examined and the causal organisms of soil-borne diseases differentiated by means of gas chromatographic analysis of their metabolic products and the long-chained fatty acids contained in the cell. With experimental clostridial vaccines prepared with the Goettingen Bioreactor Technique, trials to protect cattle and guinea-pigs against gas gangrene were carried out. It was found that the farm structure and the dry climate as well as the specific soil conditions and plant cover favour the emergence of soil-borne diseases. Causal organisms B. anthracis, C. perfringens, C. sordellii, C. haemolyticum, C. chauvoei/septicum, C. novyi A, C. botulinum and site-specific field strains of clostridia were detected. Experimental site-specific vaccines proved to be highly efficient in protecting cattle and guinea pigs.

[Electromyography as a diagnostic aid in tetanus]

In developing countries tetanus is still a real problem because of its high incidence and mortality. In all countries with high medical standards it has become rare. For this reason many clinicians are no longer familiar with the disease and its diagnosis. Until now no laboratory test has been readily available to confirm or rule out tetanus. However, the diagnosis can be performed by a simple and readily available electromyogram (EMG). We performed EMGs in 13 patients in whom tetanus was suspected but whose case history or clinical findings left some doubt. In 7 cases the EMG was typical for tetanus, showing spontaneous activity of motor units which could not be suppressed voluntarily and with shortening or absence of the silent period after a stretch reflex or after electrical stimulation of the nerve. In 2 cases we found one of the two diagnostic features. In all these 9 cases the diagnosis of tetanus was confirmed by the further development of the disease. In the remaining 4 patients the EMG was normal and in the course it was confirmed that they were not suffering from tetanus. Therefore, we consider electromyography a very useful and reliable tool either to confirm or rule out the diagnosis of tetanus.

[Protective effect in mice of the live rabies vaccine produced using the Göttingen bioreactor]

For the control of urban rabies in developing countries, the SAD-virusstrain was used in the Göttingen two-step Bioreactorsystem as a model-virus for oral vaccine production. The quality of the antigen had been tested by challenge. In the Bioreactorsystem, controlled by computer, a high standard of cell quality and cell density up to 6 x 10(6) cells/ml had been maintained. The high cell quality is correlated to high proliferation of rabies virus. Virus titres up to 10(8.5) pfu/ml were reached. The protectivity of the antigen had been tested by challenge. In comparison to a commercial vaccine with a PD50 of 10(-1.92) the SAD-Antigen of the Göttingen Bioreactorsystem reached a PD50 of 10(-1.63) by a challenge doses of 70-75 MLD50.

The accuracy of the flowrate in flush-devices of disposable pressure transducers

BACKGROUND

Arterial and venous pressure is commonly measured using fluid filled catheters. To avoid obstruction they are continuously spilled by a flush-device. The accuracy of the flowrate has not been investigated previously.

METHODS

The accuracy of 5 different flush-devices available in Switzerland was checked for flowrate when factory new, after a single sterilization with ethylen-oxide, in a long-term test over 96 hours, after repeated handling of the integrated bypass and under application of a pulsing counter-pressure.

RESULTS

Flow is linearly related to differential-pressure and is constant over time. The flow of each flush-device at 200 mmHg differential-pressure was below the indicated 3 ml per hour (1.69 - 2.49 ml/h). Sterilization in two types produced a significant but not relevant difference in flowrate. Longtime-use, bypass actuation and pulsing pressure did not alter the flowrate significantly (p <0.05). In two factory-new flush-devices and 4 re-used ones a plugged capillary induced cessation of flow.

CONCLUSIONS

Flowrate in flush-devices is accurate under sterilization, longtime use, bypass-actuation and pulsing counter pressure. A plugged capillary occurred in a few new and reused flush-devices, which can be the explanation for clotted catheters in clinical use.

[Continuous production of FMD virus in a two-step bioreactor system]

The so-called Goettingen two step bioreactor system has been tested in a pilot-project in Argentina to produce FMD-virus. With a 10-1-reactor a cell density of 3.5-4 x 10(6) cells/ml could be maintained and virus titres of up to 10(7.2) TCID/ml were reached. A correlation existed between inoculum titre and incubation period of virus. With lower inoculum a higher titre of harvested virus and a shorter incubation period were obtained. In spite of considerable problems with peripheral infrastructure and laboratory equipment the bioreactor system did work reliably. The project was terminated before final results of virus yield could be reached.