Stress Modulates the Balance between Hippocampal and Motor Networks during Motor Memory Processing.

The functional interaction between hippocampo- and striato-cortical regions during motor sequence learning is essential to trigger optimal memory consolidation. Based on previous evidence from other memory domains that stress alters the balance between these systems, we investigated whether exposure to stress prior to motor learning modulates motor memory processes. Seventy-two healthy young individuals were exposed to a stressful or nonstressful control intervention prior to training on a motor sequence learning task in a magnetic resonance imaging (MRI) scanner. Consolidation was assessed with an MRI retest after a sleep episode. Behavioral results indicate that stress prior to learning did not influence motor performance. At the neural level, stress induced both a larger recruitment of sensorimotor regions and a greater disengagement of hippocampo-cortical networks during training. Brain-behavior regression analyses showed that while this stress-induced shift from (hippocampo-)fronto-parietal to motor networks was beneficial for initial performance, it was detrimental for consolidation. Our results provide the first experimental evidence that stress modulates the neural networks recruited during motor memory processing and therefore effectively unify concepts and mechanisms from diverse memory fields. Critically, our findings suggest that intersubject variability in brain responses to stress determines the impact of stress on motor learning and subsequent consolidation.

Stress Impairs Intentional Memory Control through Altered Theta Oscillations in Lateral Parietal Cortex.

Accumulating evidence suggests that forgetting is not necessarily a passive process but that we can, to some extent, actively control what we remember and what we forget. Although this intentional control of memory has potentially far-reaching implications, the factors that influence our capacity to intentionally control our memory are largely unknown. Here, we tested whether acute stress may disrupt the intentional control of memory and, if so, through which neural mechanism. We exposed healthy men and women to a stress (n = 27) or control (n = 26) procedure before they aimed repeatedly to retrieve some previously learned cue-target pairs and to actively suppress others. While control participants showed reduced memory for suppressed compared with baseline pairs in a subsequent memory test, this suppression-induced forgetting was completely abolished after stress. Using magnetoencephalography (MEG), we show that the reduced ability to suppress memories after stress is associated with altered theta activity in the inferior temporal cortex when the control process (retrieval or suppression) is triggered and in the lateral parietal cortex when control is exerted, with the latter being directly correlated with the stress hormone cortisol. Moreover, the suppression-induced forgetting was linked to altered connectivity between the hippocampus and right dorsolateral prefrontal cortex (PFC), which in turn was negatively correlated to stress-induced cortisol increases. These findings provide novel insights into conditions under which our capacity to actively control our memory breaks down and may have considerable implications for stress-related psychopathologies, such as posttraumatic stress disorder (PTSD), that are characterized by unwanted memories of distressing events.SIGNIFICANCE STATEMENT It is typically assumed that forgetting is a passive process that can hardly be controlled. There is, however, evidence that we may actively control, to some extent, what we remember and what we forget. This intentional memory control has considerable implications for mental disorders in which patients suffer from unwanted (e.g., traumatic) memories. Here, we demonstrate that the capacity to intentionally control our memory breaks down after stress. Using magnetoencephalography (MEG), we show that this stress-induced memory control deficit is linked to altered activity in the lateral parietal cortex and the connectivity between the hippocampus and right prefrontal cortex (PFC). These findings provide novel insights into conditions under which memory control fails and are highly relevant in the context of stress-related psychopathologies.

Identification of psychological comorbidity in TMD-patients.

OBJECTIVES: The aim of the current study was to access the prevalence of depression among patients with Temporomandibular Joint Disorder (TMD) compared to patients with no current TMD. METHOD: Patients (92) and controls (90) answered questionnaires on subjective pain, severity of chronic pain, jaw disability, emotional well-being and depression, and a clinical examination was performed. RESULTS: Temporomandibular Joint Disorder patients reported higher disability of jaw function, compared to controls (p<0.001). The myoarthopathy subgroup (67.4%) had slightly more jaw disability than the myopathy subgroup (p>0.05). While 51% of TMD patients reported poor emotional well-being, only 7.8% of controls were affected (p<0.001). Clinical symptoms of depression were reported by 16% of TMD patients and not in the controls (p<0.001). Among TMD patients, a higher prevalence of depression was observed in the myopathy subgroup. DISCUSSION: A regular screening for psychological problems, using standardized questionnaires, should be integrated in clinical examination of TMD patients.

A friend in need: Time-dependent effects of stress on social discounting in men.

Stress is often associated with a tend-and-befriend response, a putative coping mechanism where people behave generously towards others in order to invest in social relationships to seek comfort and mutual protection. However, this increase in generosity is expected to be directed only towards a delimited number of socially close, but not distant individuals, because it would be maladaptive to befriend everyone alike. In addition, the endocrinological stress response follows a distinct temporal pattern, and it is believed that tend-and-befriend tendencies can be observed mainly under acute stress. By contrast, the aftermath (>1h after) of stress is associated with endocrinological regulatory processes that are proposed to cause increased executive control and reduced emotional reactivity, possibly eliminating the need to tend-and-befriend. In the present experiment, we set out to investigate how these changes immediately and >1h after a stressful experience affect social-distance-dependent generosity levels, a phenomenon called social discounting. We hypothesized that stress has a time-dependent effect on social discounting, with decisions made shortly after (20min), but not 90min after stress showing increased generosity particularly to close others. We found that men tested 20min after stressor onset indeed showed increased generosity towards close but not distant others compared to non-stressed men or men tested 90min after stressor onset. These findings contribute to our understanding on how stress affects prosocial behavior by highlighting the importance of social closeness and the timing of stress relative to the decision as modulating factors in this type of decision making in men.

The limits of agency in walking humans.

An important principle of human ethics is that individuals are not responsible for actions performed when unconscious. Recent research found that the generation of an action and the building of a conscious experience of that action (agency) are distinct processes and crucial mechanisms for self-consciousness. Yet, previous agency studies have focussed on actions of a finger or hand. Here, we investigate how agents consciously monitor actions of the entire body in space during locomotion. This was motivated by previous work revealing that (1) a fundamental aspect of self-consciousness concerns a single and coherent representation of the entire spatially situated body and (2) clinical instances of human behaviour without consciousness occur in rare neurological conditions such as sleepwalking or epileptic nocturnal wandering. Merging techniques from virtual reality, full-body tracking, and cognitive science of conscious action monitoring, we report experimental data about consciousness during locomotion in healthy participants. We find that agents consciously monitor the location of their entire body and its locomotion only with low precision and report that while precision remains low it can be systematically modulated in several experimental conditions. This shows that conscious action monitoring in locomoting agents can be studied in a fine-grained manner. We argue that the study of the mechanisms of agency for a person's full body may help to refine our scientific criteria of self-hood and discuss sleepwalking and related conditions as alterations in neural systems encoding motor awareness in walking humans.

The safety of reusing injectable collagen: a multicenter microbiological study.

We have previously reported pilot data regarding the safety of saving partially used syringes of a glutaraldehyde cross-linked collagen for use in subsequent treatment sessions with the same individual. That single institution study involved 56 partially used syringes cultured for aerobic bacteria. Only one weakly positive culture was detected among these 56 samples, which prompted us to carry out this expanded study involving multiple centers and different injection techniques. Samples were collected from four centers. Following periurethral injection in an office setting, 166 partially used syringes of glutaraldehyde cross-linked collagen were refrigerated for between 1 and 104 weeks (average 58). Material from all 166 syringes was then cultured qualitatively and quantitatively for both aerobic and anaerobic organisms. Collagen from one syringe grew >100,000 colonies of Escherichia coli. All other cultures were negative. In the pilot study, one culture of 56 syringes was weakly positive for coagulase-negative staphylococcus. When the results from both studies were considered together, only two of 222 partially used syringes (0.9%) were contaminated. The background risk of local infection associated with periurethral collagen injection is approximately 0.29%. Using the statistical equation 'number needed to harm', we found that a clinician would have to reuse 111 syringes at a saving of $34,965 before he or she would cause a single local injection by so doing. Therefore, we feel that it may be cost-effective and safe to reinject material from a partially used syringe of glutaraldehyde cross-linked collagen during a subsequent treatment session on an individual.

Is it safe to reuse a syringe of glutaraldehyde cross-linked collagen? A microbiological study.

PURPOSE: We evaluated the safety of saving partially used syringes of glutaraldehyde cross-linked collagen for subsequent treatment sessions in an individual. MATERIALS AND METHODS: After periurethral injection in an office setting 56 partially used syringes of glutaraldehyde cross-linked collagen were stored in a refrigerator for 1 to 61 weeks (mean 15). Collagen from all 56 syringes was then cultured qualitatively using a broth medium at 35C and semiquantitatively using a chocolate agar plate at 22 to 30C for 5 days each. RESULTS: A qualitative broth culture was positive for coagulase negative staphylococcus but the results of semiquantitative chocolate agar culture of material from the same syringe were negative. All cultures of the other 55 syringes were negative. CONCLUSIONS: The positive culture most likely resulted from contamination during periurethral injection or the culturing process. Minimal contamination from and the great potential cost savings of reusing glutaraldehyde cross-linked collagen for subsequent treatments in an individual indicate the need for an expanded study involving multiple centers.

Development of computerised procedures for the characterisation of the tableting properties with eccentric machines: extended Heckel analysis.

Heckel plots are a suitable and valuable method for analysis of powder compaction with very small amounts of powder. The determination is based upon a non-linear transformation of compression data and thus the signal errors that might be introduced into the analysis might be enlarged and become critical. The method of determination of true density affects the results dramatically as does the accuracy of the powder height determination. The porosity should be corrected for compression of the solid fraction. The accuracy of the powder height detection is the most demanding parameter. The statements are proven by simulations based on real data and analytic calculation. According to these highly corrected Heckel plots, the shape of the plots during the compression phase gives the information about fragmentation and plasticity and additionally about the time dependency of the compression behaviour within one compression on an eccentric press.

Development of computerised procedures for the characterization of the tableting properties with eccentric machines. High precision displacement instrumentation for eccentric tablet machines.

The paper deals with the instrumentation of displacement on an eccentric machine. Two instrumentation variants are evaluated. A displacement instrumentation consisting of two transducers attached to the frame was corrected for a slight non-linear calibration curve and corrected for machine deformation. A powder height signal was calculated from both signals. Upon dynamic punch to punch compression the powder height signal showed an oscillation of +/- 17 microns in amplitude due to tilting of the upper punch holder. A newly developed direct powder height instrumentation consisting of a set of special punches and a special die was also corrected for nonlinearities and punch deformation. The signal was free from any tilting effects and its accuracy is in the order of magnitude of the surface roughness of the punches. The machine deformation is discussed in detail. The instrumentation of the frame of the eccentric press in terms of force is possible but less sensitive by a factor of 5.4 than the use of the force sensors. The total machine deformation reaches nearly 0.5 mm under maximum load which is more than is often expected. The deformation was found to be non-linear for about 2% of the total deformation, the remaining 98% are linear deformation.

Evaluation of BACTEC 9240 blood culture system by using high-volume aerobic resin media.

The BACTEC 9240 blood culture system (Becton Dickinson Diagnostic Instrument Systems, Sparks, Md.) is one of three automated, continuous-monitoring systems that is widely used in clinical laboratories. The BACTEC 9240 was compared with the BACTEC NR 660 for the detection of organisms and bacteremic episodes; time to detection of positive cultures; number of false-positive and false-negative cultures; and time needed to load, process, and perform quality control functions by using high-volume aerobic media. Blood specimens (5,282) were inoculated in equal volumes (5 to 10 ml per bottle) into BACTEC Plus Aerobic/F (9240 system) and BACTEC Plus NR26 (660 system) bottles. Clinically significant isolates were detected in 6.6% of cultures, representing 348 microorganisms and 216 bacteremic episodes. Two hundred forty-eight microorganisms were detected by both systems, 48 by the 9240 only and 52 by the 660 only (P = not significant). Of the bacteremic episodes, 158 were detected by both systems, 27 by the 9240 only and 31 by the 660 only (P = not significant). Analysis of data by month revealed equivalent recovery rates for both systems, with the exception of a 30-day period at one study site during which the 660 system detected significantly more microorganisms. Following a proprietary hardware design retrofit of the 9240 instrument, detection rates were again equivalent for the remaining three months at this study site. Positive cultures detected by both systems were detected an average of 4.3 h faster by the 9240 system (21 versus 25.3 h). The numbers of false-positive cultures for the 9240 and 660 systems were 40 (1.0%) and 9 ( < 1.0%), respectively. The numbers of false-negative cultures were five for the 9240 system and three for the 660 system. The 9240 system required 23 s less technologist time per bottle to operate during the 5-day protocol. In conclusion, the BACTEC 9240 used with high-volume Aerobic/F medium is equivalent to the BACTEC 660 used with high volume NR26 medium for the detection of microorganisms and bacteremic episodes. In addition, the 9240 system detects positive cultures more rapidly than the 660 system but requires further evaluation to ensure reliability of instrument components.

Multicenter clinical evaluation of a continuous monitoring blood culture system using fluorescent-sensor technology (BACTEC 9240).

The BACTEC 9240 (Becton Dickinson Diagnostic Instrument Systems, Sparks, Md.) is a new continuous-monitoring blood culture system that uses internal, fluorescent-CO2 sensors. In a multicenter clinical trial, organism yield and times to detection with the prototype BACTEC 9240 system were compared with those of the BACTEC NR 660 system. Equal volumes of blood were inoculated into the bottles included in the study blood culture sets (aerobic and anaerobic 9240 and NR6A and NR7A bottles). A total of 9,391 aerobic and 8,951 anaerobic bottle pairs were inoculated with 9,801 blood specimens. A total of 587 clinically significant positive blood cultures and 415 cases of sepsis were studied. The standard 9240 aerobic bottle detected significantly more Staphylococcus aureus (P < 0.05), coagulase-negative staphylococci (P < 0.01), and total microorganisms (P < 0.001) than the NR6A bottle. The standard 9240 anaerobic bottle detected significantly more coagulase-negative staphylococci (P < 0.001), members of the family Enterobacteriaceae (P < 0.01), and total microorganisms (P < 0.001) than the NR7A bottle. A total of 420 positive cultures were detected in both systems; for 284, the time to detection was equivalent with both systems (within 12 h); for 123, the 9240 system was faster; and for 13, the NR 660 system was faster (P < 0.001). The average times to detection for the 9240 and the NR 660 systems were 20.2 and 27.5 h, respectively. Ninety-nine cultures were positive only in the 9240 system, and 68 cultures were positive only in the NR 660 system (P < 0.02). The 9240 system also detected significantly more episodes of bacteremia (P < 0.001). The false-positive rates for the 9240 and NR 660 systems were 2.2 and 2.3%, respectively. The false-negative rates for the two systems after 5 days of incubation did not differ significantly. The contamination rates for the 9240 and NR 660 systems were 1.9 and 1.5%, respectively (P < 0.05). In conclusion, the prototype 9240 system detected more clinically significant positive blood cultures and did so sooner than the NR 660 system, with the additional advantages of full automation, continuous monitoring, and noninvasive sampling.

Comparison of TestPack Plus Strep A with selective and nonselective culture media for detection of group-A streptococci.

The TestPack Plus Strep A (TPPSA), an immunoassay method, was compared with conventional culture methods including nonselective trypticase soy agar with 5% sheep blood and selective SXT blood agar for detection of group-A streptococci (GAS). A total of 452 throat swabs was evaluated, of which 261 (57.7%) and 191 (42.3%) were compared with culture using nonselective and selective media, respectively. Of 261 specimens evaluated on nonselective media, 71 (27.1%) were culture positive for GAS. TPPSA demonstrated a sensitivity of 91.6% and a specificity of 94.2% with positive and negative predictive values of 85.5% and 96.8%, respectively. Of 191 specimens evaluated on selective media, 44 (23.0%) were culture positive for GAS. TPPSA demonstrated a sensitivity of 93.2% and a specificity of 98.0% with positive and negative predictive values of 93.2% and 98.0%, respectively. The performance of TPPSA when compared with nonselective and selective media demonstrated a similar sensitivity, but a higher specificity was seen when compared to selective media. Overall, TPPSA was extremely easy to perform, had built-in procedural controls, required minimal technologist time, and was easy to interpret. With an accuracy of 93.5% when compared with nonselective media and 96.9% when compared with selective media, TPPSA could be recommended as a reliable method for detection of GAS.

A comparison of oxoid signal with nonradiometric BACTEC NR-660 for detection of bacteremia.

The Oxoid Signal (Oxoid U.S.A. Inc., Columbia, Maryland) system was compared with the nonradiometric BACTEC NR-660 (Johnston Laboratories, Towson, Maryland) system for detection of bacteria in 2714 blood cultures. The volume of blood collected into 20 ml blood-collection tubes containing sodium polyanetholsulfonate (SPS) (Becton Dickinson, Vacutainer Systems, Rutherford, New Jersey) ranged from 10 to 20 ml with an average of 15 ml. Subsequently, equal volumes of blood were inoculated into each system. A total of 250 organisms was isolated (9.6%), of which 149 (5.5%) were considered significant while 111 isolates from 98 cultures (3.6%) were contaminants. Of the significant isolates 32.9% were aerobic Gram-negative rods, 53.0% aerobic Gram-positive cocci, 5.4% anaerobes, 7.4% yeasts, and two isolates of Neisseria meningitidis. Ninety-five isolates were recovered in both systems, 29 by Bactec only and 25 by Signal only. Of the isolates recovered there were no significant differences in detection between the two systems with the exception of anaerobes (p less than 0.005). The median detection times for many of the most commonly isolated organisms--Enterobacteriaceae, streptococci, and Staphylococcus aureus--were very similar in both systems, ranging from 14 to 21 hours. With the remaining organisms recovered, the median times in hours for BAC-TEC and Signal, respectively, were 31 and 47 for Staphylococcus epidermidis, 48 and 60 for Bacteroides, 39 and 168 for yeast, and 16.5 and 168 for N. meningitidis. Oxoid Signal compares favorably with the BACTEC system. Its main advantages are: (1) it requires no instrumentation; (2) it is characterized by ease of detection; and (3) it uses a single-bottle system.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of agitation and frequent subculturing on recovery of aerobic and facultative pathogens by Roche Septi-Chek and BACTEC blood culture systems.

The positivity rate and time to recovery of pathogens were compared in Roche Septi-Chek (RSC-TSB) and BACTEC radiometric systems on 3,539 paired blood cultures. Both systems were steadily agitated, with frequent subculturing or processing of the RSC-TSB agar slides and BACTEC bottles, respectively, during the first 24 h of incubation. The RSC-TSB system recovered 249 pathogens (7.0% positivity rate), compared with 234 (6.6% positivity rate) isolates recovered from BACTEC. For the most common isolates, Staphylococcus aureus and the Enterobacteriaceae, the median time to detection was 15.8 h for BACTEC and 18.6 h for the RSC-TSB system. No statistically significant difference was observed in recovery of organisms from the two systems, except for S. aureus (P less than 0.05). In the RSC-TSB system, 42% of S. aureus, 58% of the Enterobacteriaceae, and 45% of Pseudomonas aeruginosa isolates had sufficient growth on the agar slant to allow performance of rapid standardized identification and susceptibility studies. In comparison with other studies using static incubation, it appears that agitation and frequent subculturing of the RSC-TSB system during the first 24 h of incubation decreased the time to detection for the majority of significant blood culture isolates.

Comparison of TestPack Strep A test kit with culture technique for detection of group A streptococci.

Results obtained with Abbott Laboratories TestPack Strep A (TPSA), a 7-min enzyme immunoassay method, were compared with culture results to measure the ability of this assay to detect group A streptococci directly from 365 throat swabs. Our study demonstrated a sensitivity of 90.0% and a specificity of 97.4% for TPSA compared with cultures incubated for 48 h. The positive and negative predictive values of this assay versus the culture method were 92.8 and 96.3%, respectively. If specimens that provided fewer than 10 colonies per plate of group A streptococci are eliminated from the data, the sensitivity is increased to 95.6%. Additionally, 10 group A and 40 non-group A streptococcal isolates were tested directly with TPSA for the ability to distinguish group A from non-group A streptococci. All 50 isolates were correctly identified (100% accuracy). TPSA is a rapid, accurate, and easy-to-interpret method for detection and confirmation of group A streptococcal antigen directly from throat swabs and pure culture isolates.

Verapamil disposition and effect on PQ-intervals after buccal, oral and intravenous administration.

The absorption, pharmacokinetics and effect on PQ-intervals of verapamil (Isoptin) administered as buccal tablet (20 mg), oral capsule (80-120 mg) and as an intravenous injection (5 mg) have been determined in 7 healthy subjects. Hysteresis plots of the percentage change in PQ-interval and serum concentration indicate that the efficacy of verapamil after buccal and intravenous application, as in earlier findings with sublingual verapamil tablets, was higher than after oral application. Thus the serum concentration-response curve after oral application is displaced towards the right reflecting lower potency. This phenomenon has been attributed by other workers to a stereospecific metabolism of the more active L-isomer during first pass through the liver, but competition at the receptor with metabolites cannot yet be ruled out. The rate of absorption, T1/2(alpha), terminal elimination half-life T1/2(gamma), and tmax of the buccal tablet was not significantly different from the oral capsule. The absolute bioavailability of the buccal preparation (37%) was slightly greater than the oral capsule (33%) and both had higher bioavailability than observed in earlier studies on verapamil dragees (10-20%). Thus, although the buccal tablet was alkalinised and had a rapid disintegration in vitro, characteristics thought to increase buccal uptake, the bioavailability is still much less then 100%.

[Release, absorption and elimination of theophylline from fast and slowly released oral formulations]. / Untersuchungen zur Liberation, Absorption und Elimination von Theophyllin bei rasch und verzögert freisetzenden oralen Arzneiformen.

Each 2 tablets of four tablet formulations with 150 mg theophylline were administered to 6 and 5 volunteers, respectively, as single oral dose. 8 volunteers received 256 mg theophylline as a solution and as a sustained released formulation, as well as 176 mg theophylline as short intravenous bolus infusion. The elimination was independent of the examined formulations, but differences occurred between the experiments with the different groups of volunteers. The invasion parameters (t1/2i) of the four fast released tablet formulations corresponded to the values (t1/2a) of the oral theophylline solution. Furthermore, no difference existed concerning the mean times (Tsys). The mean time (theophylline) for the body model, Tvss, is 9.9 h; the mean time, which is attributed to the absorption process (Tabs) is 0.7 h; the mean in vivo dissolution time (Tdiss-vivo) for the sustained release formulation is 6.3 h. The mean time after oral administration of the theophylline solution (Tbiol) is 10.6 h. General conditions for a comparison between the in vitro and the in vivo release data are reported.

[Pharmacokinetics and pharmacodynamics of verapamil in healthy volunteers after single oral and sublingual administration]. / Pharmakokinetik und Pharmakodynamik von Verapamil bei gesunden Versuchspersonen nach einmaliger oraler und sublingualer Applikation.

5-[3,4-Dimethoxyphenethyl)-methylamino]-2-(3,4-dimethoxyphenyl)-2- isopropylvaleronitril (verapamil, Isoptin) was administered p.o. (80 mg) and via the sublingual route (20 mg as the hydrochloride) in 6 healthy volunteers. After p.o. administration the mean peak serum concentration of 125.6 ng/ml was attained on average 80 min later. The half-life for the distribution phase (t1/2a) was 0.95 h and for the elimination phase (t1/2 beta) 6.08 h. After sublingual administration the mean peak serum concentration of verapamil was 26 ng/ml attained on average after 71.7 min. The mean t1/2a was 0.73 h and the mean T1/2 beta 4.39 h. There was an 18.4 min delay after oral administration and 0.8 min delay after sublingual administration before verapamil was detected in the serum. The relative bioavailability of verapamil sublingually was 2.7 (p.o. = 1.0). There were close correlations between the verapamil concentration in serum and the prolongation of the PQ-interval (0.725 sublingually; 0.853 p.o.). Approximately three times higher concentrations of verapamil were required when given by the oral route to produce the same prolongation of the PQ-interval obtained with sublingual administration. The variability of several important pharmacokinetic parameters of verapamil was reduced by sublingual application in comparison to the oral route. The coefficient of variation for the peak concentration, time to peak and t1/2 beta were 49.7%, 25.0% and 26.4%, respectively, after sublingual administration in comparison to 120.6%, 54.7% and 68.9%, respectively, when given p.o.

[In vivo drug release from microencapsulated acetylsalicylic acid with simultaneous alcohol uptake]. / Wirkstoff-Freisetzung aus mikroverkapselter Acetylsalicylsäure unter Alkoholbelastung.

Simultaneous uptake of different amounts of ethanol with microencapsulated acetylsalicyclic acid (Colfarit tablets) did not influence the urinary excretion of total salicylates in 7 volunteers. There was no relation to in vitro drug release.

Action of chronic peracetic acid (Wofasteril) administration on the rabbit oral mucosa.

Peracetic acid Wofasteril) is increasingly made use of as a disinfecting fluid. Because of its high effectiveness it has found widespread use in medical practice. The action of Wofasteril on the oral mucosa during long-term action is studied by aid of an "oral tank". After a test period of 11 months peracetic acid only caused a slight ballooning of the superficial layers and enhanced vascularization of the submucous tissue. The results of the experiment suggest the intraoral administration of peracetic acid in oral surgery and stomatology.