The role of microbiota and inflammation in self-judgement and empathy: implications for understanding the brain-gut-microbiome axis in depression

RATIONALE

The gut-brain axis includes bidirectional communication between intestinal microbiota and the central nervous system. Bifidobacterium and Lactobacillus spp. have been implicated in psychological health, such as depression, through various pathways (e.g. inflammation). Research needs a better understanding of direct and indirect effects through examination of psychological factors that make people susceptible to, or offer protection against, depression.

OBJECTIVE

This study investigated the relationships between gut microbiota, inflammation and psychological risk and resilience factors for depression.

METHODS

Forty participants (13 m/27 f) recruited from the general population completed self-report questionnaires for depression, self-judgement, over-identification and affective and cognitive empathy. Faecal and blood samples were taken to assay microbiota (Bifidobacterium; Lactobacillus spp.) and pro-inflammatory molecules (C-reactive protein, CRP and interleukin-6, IL-6), respectively.

RESULTS

Hierarchical regression analyses (controlling for sex, age and the shared variance of risk and resilience factors) showed that (i) cognitive depression was significantly predicted by negative self-judgement and reduced cognitive empathy; (ii) abundance of Lactobacillus spp. was directly related to positive self-judgement but only indirectly to cognitive depression and lower affective empathy (both through self-judgement); and (iii) CRP was the strongest predictor of reduced cognitive empathy, with suppression effects seen for age (negative) and IL-6 (positive) after controlling for CRP.

CONCLUSIONS

Findings suggest that lactobacilli and inflammation may be differentially associated with mood disorder via brain mechanisms underpinning self-judgement and cognitive empathy, respectively. Further trials investigating interventions to increase Lactobacillus spp. in depression would benefit from direct measures of self-judgement and affective empathic distress, whilst those that aim to reduce inflammation should investigate cognitive empathy.

Effects of whole body cryo-chamber therapy on pain in patients with chronic low back pain: a prospective double blind randomised controlled trial

BACKGROUND

It is believed that treatment with low temperature can reduce pain perception in chronic pain patients, including chronic low back pain patients.

AIM

To evaluate the effects of a two-week repeated intervention of -67 °C cryo-chamber in patients with chronic low back pain.

DESIGN

A prospective randomized double blind study design.

SETTING

Hospital-based outpatients department

POPULATION

Outpatients with chronic low back pain.

METHODS

Comparing intervention group (-67 °C) with higher temperature (-5 °C) which was supposed as a control group in a cryo-chamber.

RESULTS

Similar effectiveness in pain reduction in both intervention and control groups

CONCLUSION

Cryochamber therapy with -67 °C is not superior to (sham cryo chamber) with -5 °C.

CLINICAL REHABILITATION IMPACT

Cryo chambers therapy show positive effect by improving pain. For the treatment, -5 °C seems to be sufficient for these patients.

1. Mitt.: Versuche zur Abtrennung des pyrogenen Prinzips von Myxoviren

Die Pyrogenität des Influenzavirus A PR8 und des Newcastle disease Virus ließ sich durch wiederholtes Einfrieren und Auftauen oder Pentan-Behandlung weder abtrennen noch zerstören. Andere organische Lösungsmittel sowie oberflächenaktive Substanzen führten zu einer Zerstörung des pyrogenen Prinzips. Bei Enzymeinwirkung von Trypsin oder Phospholipase A, allein oder in Kombination, wurde ein geringer Anteil der Fieber-erregenden Aktivität abgetrennt. Ein wesentlich höherer Anteil der Pyrogenität ließ sich durch Lysozymbehandlung abspalten. Einige Hinweise sprechen für die Lipoproteinnatur der Pyrogene von Myxoviren.

Zur chemischen Natur des endogenen, durch Myxoviren induzierten Pyrogens

Die chemisch-enzymatische Charakterisierung des von Myxoviren oder bakteriellem Endotoxin in vivo und in vitro induzierten endogenen Pyrogens und des einfachen Kaninchengranulozyten-Pyrogens weist darauf hin, daß die Wirkung der endogenen Fieberstoffe an Protein gebunden ist. Filtrationsversuche mit Virus-induziertem Pyrogen aus Leukozyten sprechen für ein Mol.-Gew. um 30 000, während die Säulenchromatographie einen Bereich von 30 000 - 40 000 ergibt. Daneben treten in geringem Umfang auch größere Moleküleinheiten (Aggregate?) auf. Die mit verschiedenen Myxoviren in vitro induzierten Fieberstoffe zeigen keine Unterschiede hinsichtlich Proteinnatur und Mol.-Gew., so daß sie eng verwandt sein dürften.

[Histomorphologic findings in the facial nerve after waterjet dissection of the parotid gland. Animal studies in dogs]

BACKGROUND

The postoperative facial nerve palsy is a complication after parotidectomy which one is afraid of. The waterjet seems to be a surgical technic which allows separating different tissues without destroying important structures like vessels and nerves.

MATERIAL AND METHODS

Totally, 106 nerve preparations, done by the waterjet of 14 beagles, were evaluated. According to a defined procedure during parotidectomy by waterjet different cones and pressure were used. After a period time of 21 days the trunk, the frontal branch and both oral branches of the facial nerve of both sides were dissected. The tissue preparation was done using the standard technic for EM-sections.

RESULTS

There are mainly changes due to the preparation like the reduction of nerve fibers and fibrosis depending which cones and pressure has been used.

CONCLUSION

Therefore neither the size of the jet (120 or 150 μm) nor the operating pressure of 40 to 60 or 80 bar plays an important role for the function of the facial nerve. Damage to the nerve is mainly due to the preparation technic and the application time. Using the 200 μm jet there is regularly facial nerve damage.

[Histomorphologic findings in the facial nerve after water-jet dissection of the parotid gland in dogs]

BACKGROUND

Initial results on the application of the water-jet in a parotidectomy setting in an animal study demonstrate that there are morphologic changes which do, and some which do not, affect the clinial function of the facial nerve due to the different jet sizes and operating pressures used. In a further study the histomorphometric data of the facial nerve dissected by the water-jet should be evaluated and correlated to the different sizes of jet and operating pressures.

MATERIAL AND METHODS

In total, 102 nerves (in 14 beagles) which had been dissected by water-jets of different sizes and operating pressures were evaluated. After an observation period of 21 days, including documentation of the clinical function of the facial nerve, the nerves were dissected. The number of nerve fibers and the diameter of the different nerve fibers were then evaluated.

RESULTS

All nerve fibers dissected with jet sizes of 120 and 150 μm showed an identical cumulative frequency of fiber diameters. All nerve fibers dissected with a water-jet of 200 μm showed morphologic and clinical abnormalities and--in terms of nerve fiber diameters--clear differences to the nerve fibers dissected with 120- or 150-μm jets. Altogether, there is a decrease in fiber diameter along the nerve course.

CONCLUSION

Our data show a shift of larger diameters of the nerve trunk to smaller diameters in the terminal nerve fibers. This phenomenon has not been described in the literature to date and is probably not due to the water-jet. Additionally, our data show that 22% of the original nerve fiber damaged by the water-jet is sufficient to preserve the nerve's clinical function.

[Planning and intraoperative controls in rhinoplasty]

We present a technique to quantify computer simulation in rhinoplasty and to make individual templates to be used intraoperatively. With these templates the exact position and shape of the nasal dorsum, tip, columella and anterioar nasal spine can be controlled and adjusted. Due to our experience this techniques contributes to precise surgical outcome and patient's satisfaction.

[Magnetic coupling of partially implantable bone conduction hearing aids without open implants]

INTRODUCTION

Patients with air-bone-gaps that cannot be corrected successfully by tympanoplasty or with mixed hearing loss may be treated with bone conducting hearing aids. Their disadvantages are the obvious external fixation components or the biological and psychosocial problems of open implants.

PATIENTS AND METHODS

The principle of these new bone conducting hearing aids is the magnetic coupling between implanted and external magnets. Twin-magnets are implanted into shallow bone beds in a one step procedure. The skin above the magnets is thinned out to a thickness of 4-5 mm, which reduces the attenuation to less than 10 dB compared to direct bone stimulation.

RESULTS AND DISCUSSION

The holding strength of the external components is equivalent to partially implantable hearing aids and Cochlea implants and the hearing improvement is similar to other bone conducting hearing aids. We have found the comfort and safety of this system is significantly improved compared to conventional or percutaneous bone conducting hearing aids.

[The effectiveness of an individual mandibular advancement splint (MAS) in subjects with obstructive tongue-base-snoring]

OBJECTIVE

Besides operation the mandibular advancement splint (MAS) is one of the main options for treatment of snoring. Especially the MAS by Hinz, which exclusively blocks mandibular retrusion, has been established as an effective alternative. The aim of this study is to examine the effectiveness of this MAS and to evaluate the role of obstruction at the level of the tongue base as a successful pretherapeutic predictor by using the sleep nasal endoscopy.

SUBJECTS AND METHODS

From August 2001 until August 2006 we have examined over 450 patients with sleep disorders at our hospital. All patients have had an ENT examination, a standardized polysomnography and a sleep nasal endoscopy with therapy simulation. The application of a MAS is indicated if an obstruction at the level of the tongue base is detected and the RDI (respiratory disturbance index) is below 10/h. 10 patients are examined by PSG and partly by sleep nasal endoscopy before and after adjustment of the MAS. The patient group is classified in three velum- (n = 3), isolated tongue base-snorers, five combined tongue base-/velum- and two tongue base-/epiglottis-snorers.

RESULTS

The subjective sleep recovery and the snoring-intensity can be improved by the MAS in eight of ten patients. In addition the long-term acceptance of this therapy is very high.

CONCLUSIONS

According to our experiences the MAS by Hinz is an effective treatment option for patients with an obstruction level at the tongue base confirmed by sleep nasal endoscopy.

[Techniques in otoplasty]

A great number of surgical techniques for the correction of protruding ears have been developed. Their basic concepts originate from Mustardé's suture, the scoring technique described by Chongchet, Stenström, and Cricelair, and the combined suture and scoring technique described by Converse. Techniques for cavum rotation and lobuleplasty have also been presented. Indication, diagnostics, selection of method, the operative technique itself, and postoperative care are described. Advantages and risks of each technique are discussed, and a therapy algorithm is proposed.

Neue Wege bei der chirurgischen Behandlung der kongenitalen Geh�rgangsatresie

The rehabilitation of patients having severe malformation of the auricle with congenital auricular atresia requires plastic surgery and audiologic treatment. After classifying these malformations, various options involving hearing aids and surgery are presented. The main focus is on our new technique of combined auricular reconstruction with construction of the external ear canal and tympanoplasty, the so-called atresia-operation. It is characterised by three steps combining plastic and otologic surgery with prefabrication of the tympanic membrane and the external ear canal. Finally, our current rehabilitation concept for these patients is presented.

[Surgical treatment of severe velopharyngeal insufficiency following uvulopalatopharyngoplasty (UPPP)]

BACKGROUND

For the implementation of an uvulopalatopharyngoplasty (UPPP) it is nowadays common practice to operate in a manner which is gentle on the tissue and which retains as much muscle as possible. However, even when the greatest possible care is taken during the operation, serious complications such as persistent velopharyngeal insufficiency can arise.

PATIENT AND METHOD

Based on a case report of a 55 year old man with a persistent severe velopharyngeal insufficiency after UPPP performed at another institution and serious OSA, we suggest a so-called push back technique, adapted from the cleft-palate surgery, for the extension of the soft-palate. With regard to the operative technique, it is thus possible to produce an effective extension of the soft-palate by means of a dorsocaudal displacement of a wide and on the palatal vascular fascicle pedicled mucoperiosteum flap of the mucous membrane of the hard palate, as well as similar mobilisation of the soft-palate from the os-palatinum.

RESULT

Only 3 weeks after the operation, our patient showed a clinically sufficient velopharyngeal functioning. After 3 months, a complete restoration of the nasal CPAP-acceptance was evident. As a result, a complete social rehabilitation was possible for our patient.

CONCLUSION

The modified push back technique of the palate retrodisplacement which is described above offers an efficient possibility of anatomically and functionally correcting the persistent and serious velopharyngeal insufficiency after UPPP.

Comparison of the efficacy and safety of moxifloxacin and trovafloxacin for the treatment of acute, bacterial maxillary sinusitis in adults

In this multicentre, multinational, comparative, double-blind clinical trial, out-patients with both symptoms and radiographic evidence of acute sinusitis were randomly assigned to receive either a seven-day, once daily (o.d.) oral regimen of moxifloxacin (400 mg) or a 10-day o.d. oral regimen of trovafloxacin (200 mg). Among 452 patients considered valid for clinical efficacy, moxifloxacin treatment was found to be statistically equivalent to trovafloxacin (96.9 per cent vs 92.1 per cent -95 per cent CI = 0.6 per cent; 8.9 per cent) at the seven to 10 days post-therapy assessment. At follow-up, the success rate in the moxifloxacin group was 94.9 per cent and that for the trovafloxacin group was 97.6 per cent (95 per cent CI = -4.9 per cent; 1.3 per cent). The predominant causative organisms were Streptococcus pneumoniae, Haemophilus influenzae and Staphylococcus aureus followed by Enterobacteriaceae and Moraxella catarrhalis. The bacteriological success rate at the post-therapy evaluation was similar in both treatment groups: 94.4 per cent and 90.1 per cent in the moxifloxacin and trovafloxacin groups respectively (95 per cent CI = -3.0 per cent; 11.9 per cent). Only three of the 103 baseline isolated pathogens still persisted in the moxifloxacin group, whereas there were 10 of the 121 isolates that failed to respond in the trovafloxacin treatment group. At least one drug-related event was reported by 16.9 per cent of the moxifloxacin-treated patients and by 22.3 per cent of those who received trovafloxacin. CNS events such as dizziness and vertigo were reported more than five times more often in patients receiving trovafloxacin than in the moxifloxacin group. Trovafloxacin recipients were also more than twice as likely to discontinue treatment due to adverse events than moxifloxacin-treated patients. Overall, moxifloxacin was at least as effective clinically and bacteriologically as trovafloxacin and better tolerated.

[Reconstruction after extended partial laryngeal and hypopharyngeal resections. A new method with rib cartilage, chondrosynthesis and free radial transplants]

Partial pharyngectomy combined with subtotal laryngectomy results in permanent tracheostomy and long lasting swallowing difficulties in many cases. Based on our prior experimental and clinical studies on laryngeal chondrosynthesis the objectives of this project were to develop a method for reconstruction of up to two thirds of the larynx and one pyriform sinus.

METHOD

The resected laryngeal framework is reconstructed with autogenous rib cartilage and stabilized with plates and screws. In addition a piece of cartilage is used as a buttress for apposition by the remaining mobile vocal cord. A free radial forearm flap covers the reconstructed framework and forms the sulcus of the pyriform sinus.

RESULTS

Up to now 7 patients have been operated with this technique. The follow up was 35 months on average. None of the patients has a clinically relevant aspiration. All patients have a well understandable voice and one of them--a teacher--could even resume his speech profession.

CONCLUSION

In selected patients these techniques enable functional rehabilitation of swallowing, breathing and speech even after extended partial pharyngolaryngectomy.

Water-jet dissection in parotid surgery: an experimental study in dogs

OBJECTIVE

The objective of the present study was to investigate the application of the water-jet dissection method in parotid surgery by way of animal experiments, paying particular attention to the clinical and histological reactions of the facial nerve.

STUDY DESIGN

An animal experimental study.

METHODS

Total bilateral parotidectomies with retention of the facial nerve were performed on 19 beagle dogs by means of the Hydro-Jet device (Andreas Pein Medizintechnik Company, Schwerin, Germany) using different jet diameters and operating pressures. All operations were performed with continuous intraoperative facial monitoring (Neurosign 100, Inomed Company, Teningen, Germany). The dogs were monitored postoperatively over an average period of 20.3 days (range, 14-35 d). Local findings and facial nerve status were documented daily. In a second phase, the dissected nerves were resected and the animals were killed. Samples of water-jet-dissected parotid tissue, as well as all dissected nerve branches, underwent histological examination and were compared with clinical and electrophysiological findings.

RESULTS

It was possible to perform operations easily on all parotid glands by means of the Hydro-Jet using the small, 120-microm jet at operating pressures of 40 to 60 bar and to dissect the facial nerve quickly and safely with retention of its functional capability (n = 34). The dissection of nerves using larger-diameter jets (150 and 200 microm [n = 64]) resulted in a total of two reversible and seven irreversible partial pareses.

CONCLUSIONS

The study has shown that it is possible to perform tissue-selective operations on the parotid gland by means of the Hydro-Jet using the 120-microm jet at operating pressures of 40 to 60 bar, ensuring safe, atraumatic dissection of the facial nerve with retention of its functional capability. The advantages of the new Hydro-Jet method offer a valuable alternative compared with the normal dissection methods adopted in parotid surgery. Thus the results of the present investigation currently are being checked within the framework of a clinical study at our clinic.

Two-Step External Ear Canal Construction in Atresia as Part of Auricular Reconstruction

OBJECTIVES

One of the common complications of atresia surgery is restenosis of the surgically constructed external ear canal. To avoid this complication, a new two-step technique of creating an external ear canal was developed and evaluated.

STUDY DESIGN

Prospective clinical evaluation.

PATIENTS AND METHODS

Thirty-six patients with third-degree microtia and aural atresia have been treated this way. In the first step, the canal is drilled into the petrous bone, a Silastic cylinder is inserted and wrapped into pieces of cartilage and bone dust. In the second step several months later, the implant is removed and a slightly smaller tube covered with a split thickness skin graft is inserted.

RESULTS

Except the first three patients operated with a slightly different technique, none of the following 33 patients showed a severe restenosis. Instead, all had a nice, smooth external ear canal.

CONCLUSION

With this two-step technique of creating a new external ear canal in atresia, we could avoid one of the major complications of this kind of surgery. The external ear canal is either necessary for the reconstructed middle ear or it can be used to adapt a (behind or in the ear) hearing aid. By integrating this technique into a three-step concept for auricular reconstruction, the patient does not need any additional operation, and his or her rehabilitation from ear malformation can be enhanced.

[Water-jet dissection in parotid surgery--initial clinical results]

INTRODUCTION

The most frequent complication following parotidectomies is postoperative facial nerve dysfunction. In animal experiment we successfully studied the technique of water-jet-dissection for safe and functional preservation in facial nerve dissection in parotid gland surgery. The aim of the present study was to evaluate our animal experiments clinically.

METHODS

Until November '99 ten patients with benign parotid gland tumors (4 female, 6 male, age 32-77 years) underwent lateral or latero-segmental parotidectomies using water-jet-dissection ("Hydro-Jet", Andreas Pein Medizintechnik GmbH, Schwerin, Germany). All operations were performed under permanent intraoperative facial nerve monitoring ("Neurosign 100", Fa. Inomed, Tenningen, Germany). The postoperative facial nerve function was measured daily by the House-Brackmann and Stennert-Paresis-Index for at least one week.

RESULTS

A quick parotid gland and safe facial nerve dissection could be performed in all operations using the 120 microns-nozzle with effective working pressures from 30-50 bar. In addition strong connective tissue fibers were transected with scissors. Intraoperative facial nerve lesions did not occur and cardiopulmonary complications due to eventual cutting-fluid-resorption were not seen. After surgery all patients had a normal facial nerve function.

DISCUSSION

The results of our studies showed that the technique of water-jet-dissection provides safe facial nerve dissection and preservation during parotid gland surgery.

CONCLUSIONS

The tissue selective cutting qualities of the new surgical method are an excellent alternative compared to standard dissection methods in parotid surgery.

Structure of the molecular chaperone prefoldin: unique interaction of multiple coiled coil tentacles with unfolded proteins

Prefoldin (GimC) is a hexameric molecular chaperone complex built from two related classes of subunits and present in all eukaryotes and archaea. Prefoldin interacts with nascent polypeptide chains and, in vitro, can functionally substitute for the Hsp70 chaperone system in stabilizing non-native proteins for subsequent folding in the central cavity of a chaperonin. Here, we present the crystal structure and characterization of the prefoldin hexamer from the archaeum Methanobacterium thermoautotrophicum. Prefoldin has the appearance of a jellyfish: its body consists of a double beta barrel assembly with six long tentacle-like coiled coils protruding from it. The distal regions of the coiled coils expose hydrophobic patches and are required for multivalent binding of nonnative proteins.

[Bilateral acoustic trauma after air bag inflation]

Airbag inflation is associated with a loud noise. This very short noise has a peak amplitude of 170 dB sound pressure level and can make otologic injuries. We report a case of acoustic trauma after airbag inflation. The 24-year-old man has hearing loss both side in the 3000- to 6000-Hz range and in the deep-frequency. The possibility of acoustic trauma from airbag noise are probably much more common and need more attention in the clinic.

A comparison of the safety and efficacy of moxifloxacin (BAY 12-8039) and cefuroxime axetil in the treatment of acute bacterial sinusitis in adults. The Sinusitis Study Group

The aim of this multicentre, randomized study was to compare the efficacy and safety of moxifloxacin (BAY 12-8039), a new 8-methoxy fluoroquinolone, with that of cefuroxime axetil for the treatment of acute bacterial sinusitis in adults. Diagnosis was made on a range of clinical signs and symptoms combined with radiology and microbiology. A 400 mg dose of moxifloxacin was administered once daily for 7 days to 242 patients and 250 mg twice daily of cefuroxime axetil was administered to 251 patients for 10 days. The clinical success rate at the end of treatment in the evaluable population was significantly higher (96.7%) in the moxifloxacin group (204/211) than in the cefuroxime axetil group (204/225, 90.7%; 95% confidence intervals 1.5%; 10.6%). At follow-up the success rate in the moxifloxacin group was 90.7% and that for the cefuroxime axetil group was 89.2% (95% confidence intervals -4.3%; 5.4%). The predominant pathogens isolated were Streptococcus pneumoniae and Haemophilus influenzae, followed by Moraxella catarrhalis and Staphylococcus aureus. The bacteriological eradication rates were higher for moxifloxacin (94.5%, 103/109) than for cefuroxime axetil (83.5%, 96/115; 95% CI 3.6%; 19.7%). Only one S. pneumoniae infection persisted following moxifloxacin therapy in contrast with three in individuals on cefuroxime axetil. There were slightly more adverse events in the moxifloxacin group than in the cefuroxime axetil group, but there were fewer serious adverse events following moxifloxacin treatment (three vs. eight). The drug was discontinued because of adverse events in 14 moxifloxacin patients and in 11 cefuroxime axetil patients. Overall, in all assessments, moxifloxacin was at least as effective clinically and bacteriologically, and as well tolerated, as cefuroxime axetil in the treatment of acute sinusitis.

The effect of tissue expansion on the expression of collagen type I and type III mRNA in distinct areas of skin in the dog as an animal model

To evaluate the transcriptional response of skin to tissue expansion in the dog, the expression of procollagen alpha 1(I) mRNA and procollagen alpha 1(III) mRNA were analyzed by in situ hybridization. This expression was evaluated in distinct skin areas (subepidermal zone, dermis, capsular zone) after 4-85 days of expansion. Within the first 4 days of expansion expression of procollagen alpha 1(I) and alpha 1(III) mRNA was not affected in the subepidermal and dermal zone. Only a slightly elevated level of type III procollagen mRNA was demonstrated in tissue surrounding the implanted silicone expander. After 7 days of expansion an enhanced level of procollagen alpha 1(III) mRNA was observed in the dermis and capsular zone. A slightly enhanced type I collagen mRNA level occurred in all zones of the dermis that was even stronger in the capsular zone after 9 days of expansion. Concurrently, the number of transcriptionally active cells was significantly higher. Return to the basal level of procollagen alpha 1(I) mRNA was attained after 40 days. At this time a significant expression of procollagenase mRNA was observed. Procollagen III mRNA expression reached its basal level on day 85.

Lipid patches in membrane protein oligomers: crystal structure of the bacteriorhodopsin-lipid complex

Heterogenous nucleation on small molecule crystals causes a monoclinic crystal form of bacteriorhodopsin (BR) in which trimers of this membrane protein pack differently than in native purple membranes. Analysis of single crystals by nano-electrospray ionization-mass spectrometry demonstrated a preservation of the purple membrane lipid composition in these BR crystals. The 2.9-A x-ray structure shows a lipid-mediated stabilization of BR trimers where the glycolipid S-TGA-1 binds into the central compartment of BR trimers. The BR trimer/lipid complex provides an example of local membrane thinning as the lipid head-group boundary of the central lipid patch is shifted by 5 A toward the membrane center. Nonbiased electron density maps reveal structural differences to previously reported BR structures, especially for the cytosolic EF loop and the proton exit pathway. The terminal proton release complex now comprises an E194-E204 dyad as a diffuse proton buffer.

Dermal microvasculature and tissue selective thinning techniques (ultrasound and water-jet) of short-time expanded skin in dogs

Certain reconstructive procedures, like auricular reconstructions, require thin and well-vascularized skin. The aims of this study were to analyze if the increased survival of expanded skin flaps was due to morphologic changes of the dermis, if thinning of short-time expanded skin was possible without harm to the microcirculation and if tissue selective cutting methods could be used to resect subcutaneous fat without damaging its vessels. Eighty-two 200-ml expanders were implanted into the trunk regions of 26 beagles and filled immediately with sterile saline. In the first series of experiments, the expansion was terminated after intervals of 0.5-5 weeks and dermal vessels were analyzed morphometrically. In the second series the expanded flaps were raised after 2 weeks and thinned solely surgically or with the additional use of an ultrasonic knife or with cutting by water jet. In contrast to sham flaps, the expanded skin showed only very few areas of necrosis and these were located superficially in most cases. The relative volume of the dermal vessels and their quantity showed a significant increase after the expansion. Additionally, the subcutaneous tissue could be thinned down to 0.4 mm with the water-jet-cutter. Findings demonstrated that the method used could create a well-vascularized skin flap of minimal thickness that could be very helpful for special reconstructive procedures.