Platelet-rich plasma, platelet-rich fibrin, and enamel matrix derivative for oral mucosal wound healing.

Different approaches to enhance healing of hard or soft tissues include the use of cytokines and growth factors to modify cellular behaviour. Numerous growth factors are found in autologous blood concentrates - platelet-rich plasma (PRP) and platelet-rich fibrin (PRF). Enamel matrix derivative (EMD) may improve tissue healing via amelogenins. Bilayered collagen matrix (CM) is used for soft tissue augmentation. The aim of the present study was to assess potential benefits of PRP, PRF and EMD in combination with bilayered collagen matrix or CM alone in treatment of oral mucosal defects in rabbits. Twenty-seven New Zealand white rabbits were included in this randomized controlled trial. Artificial oral mucosal defects were treated with one of these five approaches: PRP+CM, PRF+CM, EMD+CM, CM alone, or left untreated as a negative control - CO. The animals were euthanized 1 day, 7 days, or 28 days after surgery and necropsies were harvested. Histological and molecular biological analyses were performed. All defects were healed by day 28. No differences between PRP+CM, PRF+CM, CM alone and CO groups were recorded at any time point. Slower angiogenesis and a higher presence of inflammatory infiltrate were observed in the EMD+CM group 28 days after surgery. Molecular biological analyses did not reveal any statistically significant changes. In conclusion, no improvement in mucosal healing of wounds covered with a collagen membrane and PRP, PRF, or EMD was observed, compared with CM alone or untreated controls.

VASOSPASM OF THE FLAP PEDICLE--MAGNESIUM SULPHATE RELIEVES VASOSPASM OF AXIAL FLAP PEDICLE IN PORCINE MODEL.

BACKGROUND: The effect of magnesium sulphate on mechanically provoked vasospasm of the flap pedicle on porcine model was not studied yet. Positive effect of magnesium sulphate on vasospasm was proved in previous studies on rat. METHODS: The bilateral pedicled flaps based on the caudal superficial epigastric arteries were raised on 8 pigs. Flaps on the right side were the treatment group; flaps on the left side were the control group. The vasospasm was provoked by the tension applied on the pedicle in the axial direction using 160g weight. The blood perfusion of the flap was monitored using laser-Doppler. The duration of the vasospasm was defined as the time from the release of the tension until the blood flow began to rise. These times were detected using an automated computerized detection. In the treatment group, magnesium sulphate was given topically on the vessel; saline was used in the control group. RESULTS: The duration of the vasospasm in the treatment group was significantly shorter than in the control group (P = 0.024). CONCLUSION: Magnesium sulphate 10% shortened significantly the mechanically provoked vasospasm on caudal superficial epigastric flap in a porcine model. Further clinical studies are needed to prove the effect in humans.

The effects of live yeast Saccharomyces cerevisiae on postweaning diarrhea, immune response, and growth performance in weaned piglets.

The effects of live yeast Saccharomyces cerevisiae (strain CNCM I-4407, 10(10) cfu/g; Actisaf; Lesaffre Feed Additives, Marcq-en-Baroeul, France) on the severity of diarrhea, immune response, and growth performance in weaned piglets orally challenged with enterotoxigenic Escherichia coli (ETEC) strain O149:K88 were investigated. Live yeast was fed to sows and their piglets in the late gestation, suckling, and postweaning periods. Sows were fed a basal diet without (Control; n = 2) or with (Supplemented; n = 2) 1 g/kg of live yeast from d 94 of gestation and during lactation until weaning of the piglets (d 28). Suckling piglets of the supplemented sows were orally treated with 1 g of live yeast in porridge carrier 3 times a week until weaning. Weaned piglets were fed a basal starter diet without (Control; n = 19) or with (Supplemented; n = 15) 5 g of live yeast/kg feed for 2 wk. Significantly lower daily diarrhea scores (P < 0.05), duration of diarrhea (P < 0.01), and shedding of pathogenic ETEC bacteria (P < 0.05) in feces was detected in the supplemented piglets. Administration of live yeast significantly increased (P < 0.05) IgA levels in the serum of piglets. Evidence indicates that decreased infection-related stress and severity of diarrhea in yeast-fed weaned piglets positively affected their growth capacity in the postweaning period (P < 0.05). The results suggest that dietary supplementation with live yeast S. cerevisiae to sows and piglets in the late gestation, suckling, and postweaning periods can be useful in the reduction of the duration and severity of postweaning diarrhea caused by ETEC.

Passive immunisation of post-weaned piglets using hyperimmune serum against experimental Haemophilus parasuis infection.

The protective role of hyperimmune serum in the prevention of Haemophilus parasuis infections in post-weaned piglets was assessed by experimental challenge. The hyperimmune serum was obtained from a pig vaccinated with a commercial vaccine against Glässer's disease. Thirty-eight weaned piglets were divided into four groups: three groups were immunised intramuscularly with 10 ml of hyperimmune serum and one group consisted of unimmunised control animals. All piglets were subsequently infected intraperitoneally with H. parasuis serotype 5 at different times after immunisation. The use of hyperimmune serum provided the piglets with partial protection against experimental infection. The levels of protection indirectly depend on time between serum inoculation and challenge infection. The best protection of piglets against experimental infection was obtained in the group immunised 1 week before inoculation; the same group in which the highest levels of antibodies were detected at the time of challenge.

[The effect of chelidonium- and turmeric root extract on upper abdominal pain due to functional disorders of the biliary system. Results from a placebo-controlled double-blind study]. / Die Wirkung von Schöllkraut- und Curcumawurzelstock-Extrakt auf Oberbauchbeschwerden infolge funktioneller Störungen des ableitenden Gallensystems. Ergebnisse einer plazebokontrollierten Doppelblindstudie.

BACKGROUND: Right upper abdominal pain may often be caused by biliary dyskinesia. Choleretica and cholekinetica are widely used for medical treatment of complaints due to biliary dyskinesia despite of a lack of randomized clinical trials which may prove their efficacy and potency. PATIENTS AND METHODS: The present prospective multicenter pilot study analyzes the effects of Cholagogum F Nattermann (dried extracts from Schöllkraut and Curcuma) in comparison with placebo in patients with dumpy or colicky abdominal pain in the right upper quadrant due to biliary dyskinesia. Cholagogum was given in 39 patients and placebo in 37 patients for 3 weeks, respectively. RESULTS: The reduction of dumpy and colicky pain was more rapid during the first treatment week in patients who received Cholagogum F when compared to those who received placebo. The reduction of other complaints (feeling of being filled up, food intolerance, nausea, vomiting, meteorism) (secondary variables) was similar in patients who received Cholagogum F versus placebo during the whole treatment period. The were no side-effects in patients who received Cholagogum. CONCLUSIONS: The study presents the first solid indication that extracts from Schöllkraut/Curcuma (Cholagogum F Nattermann) which have widely been used in daily practice for many decades have beneficial effects on pain due to biliary dyskinesia.

Polyunsaturated phosphatidyl-choline and interferon alpha for treatment of chronic hepatitis B and C: a multi-center, randomized, double-blind, placebo-controlled trial. Leich Study Group.

BACKGROUND/AIMS: Polyunsaturated phospatidyl-choline (PPC) has been shown to reduce serum aminotransferases in experimental hepatitis. This multi-center, randomized, double-blind, placebo-controlled trial evaluated the effects of PPC in patients with chronic hepatitis B and C in combination with interferon alpha 2a or 2b. The diagnosis of chronic viral hepatitis was based on an abnormal serum alanine aminotransferase (ALT) value (more than twice the upper value of normal), viral replication and chronic hepatitis found on liver biopsy. METHODOLOGY: Patients received 5 million I.U. (Hepatitis B) and 3 million I.U. (hepatitis C) interferon s.c. thrice weekly for 24 weeks, respectively, and were randomly assigned to additional oral medication with either 6 capsules of PPC (total daily dose: 1.8 g) or 6 capsules of placebo per day for 24 weeks. Biochemical response to therapy was defined as a reduction of ALT by more than 50% of pre-treatment values. The responders were treated for further 24 weeks after cessation of interferon therapy with either PPC or placebo. RESULTS: 176 patients completed the study protocol (per-protocol population: 92 in the PPC and 84 in the placebo group). A biochemical response (> 50% ALT reduction) was seen in 71% of patients who were treated with PPC, but only in 56% of patients who received placebo (p < 0.05). PPC increased the response rate in particular in patients with hepatitis C: 71% of those patients responded in the PPC group versus 51% in the placebo group (p < 0.05). Prolonged PPC therapy given to responders beyond the cessation of interferon therapy tended to increase the rate of sustained responders at week 48 in patients with hepatitis C (41% versus 15% in the control group; p = 0.064). In contrast, PPC did not alter the biochemical response to interferon in patients with hepatitis B. PPC did not accelerate elimination of HBV-DNA, HBeAg and HCV-RNA. CONCLUSIONS: In conclusion, PPC may be recommended in patients with chronic hepatitis C in combination with interferon and after termination of interferon in order to reduce the high relapse rate. PPC may not be recommended for patients with chronic hepatitis B. In contrast to IFN and other antiviral agents PPC does not carry major risks and is tolerated very well.

Motion VEPs with simultaneous measurement of perceived velocity.

The dependency of the N200 amplitude of the motion-onset VEP evoked by a parafoveal grating of variable speed (0.25-13.5 deg/s, corresponding to 0.5-27 Hz) and constant contrast (4%) was studied. Additional measurements were made with parafoveally presented gratings of constant speed (2 deg/s, corresponding to 4 Hz) and a variable contrast (0.5-64%) before and after adaptation to a stationary or drifting grating. In this latter experiment, simultaneous psychophysical measurements were made of the perceived speed. The amplitude of the N200 wave increased with increasing stimulus speed within the slow speed range up to 1.5 deg/s (corresponding to 3 Hz). Adaptation to a stationary grating had no significant effect on the relationship between the N200 amplitude and stimulus contrast. Contrary to this, adaptation to a slowly drifting grating (1 deg/s, corresponding to 2 Hz) or to a rapidly drifting grating (4 deg/s, corresponding to 8 Hz) reduced the N200 amplitude significantly. Adaptation to a stationary grating slightly reduced the perceived speed of subsequently viewed gratings. Adaptation to a slowly drifting grating increased the perceived speed of the subsequently viewed gratings, whereas adaptation to a rapidly drifting grating decreased the perceived speed. The findings can be best explained by a two-channel model of speed perception. While the motion VEP reflects the sum of both channel activities, the psychophysical measures point to the antagonistic encoding of low and high velocities.

Similarities and dissimilarities between pattern VEPs and motion VEPs.

The contrast response functions (CRF) of pattern-appearance and motion-onset VEPs for periodic stimuli (gratings) were compared. The CRF for pattern-appearance is accelerative for the P100 component and compressive for the N200 component. Contrary to these results, the CRF for motion-onset shows an almost negligible slope for both components within the contrast range tested (0.5-64%). To better isolate the neural contributions to these different VEP components, we studied the effects of prior adaptation to stationary and moving gratings. Adaptation to stationary gratings has no effect on both VEP components for motion-onset and the P100 component for pattern-appearance, but did reduce the amplitude of the N200 for pattern-appearance. Adaptation to slow (1 deg/s) and fast (4 deg/s) gratings left the P100 amplitudes unaltered, while it significantly reduced the N200 amplitudes for both pattern-appearance and motion-onset. These results suggest that the N200 component of the motion-onset VEP is generated by motion-dependent neurons, whereas the same component for pattern-appearance arises from contrast-dependent neurons. The observed differences between P100 and N200 components appear to reflect the activity of both transient and sustained neural mechanisms.

[Motion-onset visually evoked potential with nasal and temporal half- and full-field stimulation]. / Durch Bewegungsbeginn visuell evozierte Potentiale bei Stimulation von nasalen und temporalen Halbfeldern sowie bei Ganzfeldreizung.

The known proportional increase in the amplitude of the pattern reversal visually evoked potential (VEP) with increasing stimulus area does not occur for the motion-onset VEP. When the stimulus area of the total field (6 degrees x 6 degrees) is compared to that of the half-field (6 degrees x 3 degrees), the N200 amplitude of the motion-onset VEP is not changed proportionally but remains almost constant. Reducing the pattern contrast beyond the saturation value for the motion-VEP yields essentially the same results. Contrary to the pattern reversal VEP, the amplitudes of the motion-onset VEP are found to be more pronounced for the nasal than for the temporal hemiretina. Our results support the notion of a genuine difference between the pattern- and the motion-analyzing visual system.

The human motion VEP as a function of size and eccentricity of the stimulation field.

A 'motion onset VEP' was elicited by the onset of a pattern drift. The amplitude of the most distinct wave (AN200) was determined on the following stimulation conditions: eccentricity, 0 to 23 deg; velocity. 1.5 to 16 deg/s; spatial frequency, 0.19 to 2.1 c/deg; and stimulation field size, 0.2 to 160 deg2, AN200 remained constant at any degree of eccentricity if stimulation field size, velocity, and spatial frequency were M-scaled according to Rovamo-Virsu's M-equations. AN200 decreased as a function of eccentricity if field size and velocity were kept constant (spatial frequency had minimal effect). The size of the cortical representation field (Sc) in this case varied with change in eccentricity (stimulation field size constant). In another experiment, it varied by change in stimulation field size (eccentricity constant). For both conditions, AN200 was proportional to log Sc.

The human motion onset VEP as a function of stimulation area for foveal and peripheral vision.

We studied amplitude of the wave N200 of the motion-onset VEP by varying the side length of a square stimulation field between 0.5 and 7 degrees. A significant increase in amplitude was obtained between 0.5 and 1 degree of side length in central stimulation and between 0.5 and 5 degrees in 10-degree peripheral stimulation. Variations of spatial frequency between 0.34 and 6.8c/deg did not modify the amplitude size, ie, no tuning effect could be found. The results of simultaneous and separate stimulation of foveal and parafoveal regions support the observation that the stimulation field size is a minor influence. Features of motion-sensitive cortical neurons, such as those found in monkeys, could account for this behavior.

[Topography of the movement visual evoked potential in the human]. / Zur Topographie des Bewegungs-VEP am Menschen.

The amplitudes of the motion VEP waves P100, N200 and P300 were investigated on 12 subjects at six electrode positions (2.5, 5, 7.5 and 10 cm above the inion and 5 cm bilaterally from the 2.5 cm midline point). The evaluation was performed on the basis of in general 45 (for P100 32) averaged potentials per subject. Each averaged potential was obtained from 40 single potentials. P100: The amplitudes were nearly equal at all electrodes. N200: The greatest amplitudes could be found at the lateral electrodes. The amplitudes decreased in the midline in occipito-frontal direction reaching the lowest value at the electrode most frontally situated. P300: This wave had its greatest amplitude at the most frontal lead position. The amplitude decreased systematically in occipital direction. The differences in the position of the amplitude maxima and in the topographical distribution of the remaining amplitude values suggest different generator structures of the waves N200 and P300.

The influence of grating contrast on the human cortical potential visually evoked by motion.

A cortical potential was evoked by the onset of horizontal drift of a previously stationary vertical square-wave grating (motion-on VEP). The influence of contrast on the principal VEP waves N2 and P2 (peak latencies 180-220 ms and 250-350 ms, respectively) was investigated in five subjects for velocities between 0.3 and 4.1 deg/s, a spatial frequency of 2.6 c/deg and a mean luminance of 17 cd/m2. For low contrasts an ascending linear relation could be found between wave amplitude and logarithm of contrast, and a descending one between wave peak latency and log contrast. The waves remained constant for moderate and high contrasts. The lowest contrast value at which wave constancy occurred (saturation contrast) was determined by a method of least squares. All the data summarized yielded a saturation contrast of 0.058 for N2 and 0.084 for P2. The saturation contrast of the pattern VEP already known from the literature is essentially greater under comparable experimental conditions.

Influence of velocity, temporal frequency and initial phase position of grating patterns on motion VEP.

The cortical potential visually evoked by motion of a periodic grating (motion VEP) is composed of a transient component which decays within 500 ms of stimulus-onset (motion-on VEP) and a sustained component. Amplitude and peak latency of wave N2 of the motion-on VEP are functions of grating velocity. Both remain constant at spatial frequencies between 0.6 and 4.3 c/deg and at temporal frequencies within the equivalent intervals. The transient component of the motion VEP is independent of the spatial phase position of the grating before motion onset. The sustained component can only be seen in the averaged motion VEP at constant phase position of the grating before motion onset. This potential consists of periodical fluctuations with a main frequency equal to the temporal frequency of the moving grating. As a result of psychophysical investigations some authors suggest pattern velocity is the relevant variable of velocity perception, others temporal frequency. The motion VEP is dependent on both velocity and temporal frequency, the transient component is a function of velocity, the sustained component of temporal frequency.

The effect of movement adaptation on human cortical potentials evoked by pattern movement.

Human visually evoked cortical potentials (VEPs) were elicited by the onset of movement of grating patterns (test stimuli). The most prominent VEP waves N2 and P2 increased with accelerating test stimulus velocity (within a range of 0.2-4 deg/s). Two kinds of rums were presented. Reference runs involved only test stimuli and stationary pattern periods between them. In test runs moving gratings were additionally presented between the test stimuli effecting a stable level of movement adaptation. The additional movement stimulation reduced the VEP amplitudes throughout. The relative amplitude reduction was nearly constant for all test stimulus velocities if a fixed velocity of the adaptation stimulus was used. When the adaptation stimulus velocity was raised (within a range of 0.1-4 deg/s), the relative VEP amplitude became smaller. The results support the additive model of velocity coding in human occipital cortex rather than the substitutive model.

[Visual evoked potential studies on human cortical coding of the speed of movement of a grating pattern]. / VEP-Untersuchungen zur Kodierung der Geschwindigkeit bewegter Streifenmuster im Kortex des Menschen.

Knowledge referring to the kind of velocity coding in human cortex can be obtained either by psychophysical methods or by recording of visually evoked cortical potentials (VEPs). With the help of adaptation experiments it is possible to distinguish between the additive and substitutive coding principle. VEPs were evoked by the onset of movement of a grating pattern (test stimulus). The most prominent waves N2 and P2 increased with accelerating test stimulus velocity within a range of 0.2-4 deg/s (see strong curve in Fig. 6a and 7a). Moving gratings (adaptation stimuli) were additionally presented in corresponding runs during the intervals between the test stimuli to attain a stable level of movement adaptation. The additional movement stimulation reduced the VEP amplitudes in general (see weak lines in Figs. 6a, 7a and relative amplitudes in Figs. 6b, 7b). When the adaptation stimulus velocity was raised within a range of 0.1-4 deg/s (see values of the abscissas in Figs. 6 and 7 indicated by symbols with arrow) the relative VEP amplitude became smaller (decrease from curve to x). This result points to the validity of the additive coding principle. The different behavior of the delta-curve supports the hypothesis of a second channel for velocities faster than 1 deg/s.

[Visual evoked potentials in pattern motion]. / Visuell evozierte Potentiale bei Musterbewegung.

Our intention was to obtain a visual evoked potential (VEP) consisting only of a movement-related component for the purpose of further investigations of movement detection. This was attempted by selection of appropriate stimulus conditions. Evoked by initial movement a VEP with five typical waves was observed at the human occipital scalp. The N2-wave with a peak latency of 180-200 ms was most prominent. Following results were yielded in the experiments carried out: 1. Adaptation to a pattern movement: The amplitude of N2 and P1 is significantly reduced (Fig. 4). 2. Relation between amplitude and velocity: The experimental data could be approximated by a power function with an exponent of m = 0.3 for N2 and lower m for later waves (Fig. 5). 3. Pattern variation (grating, checkerboard, zig-zag) had no influence on N2 but on P1 and possibly also on later waves (Fig. 6). These results suggest that the wave N2 is movement-related under our experimental conditions. A pattern-related component may additionally be assumed in wave P2. Components, evoked by further reasons, may be included in the waves following N2. Their specification demands supplementary experiments.