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Biomedical subjects

A Gunkel

Publications and source records attributed to A Gunkel.

At least 19 recordsLinked to original sources
PubMed2004

[Emergency free microvascular flap transfer for repair of a pharyngeal defect manifesting as carotid artery erosion hemorrhage].

We report on a case of an emergency free flap cover of a pharyngeal defect which was made necessary by aggressive digestive salivatory and radiation effects 3 weeks after neck-dissection and laser ablation of an epidermoid left tonsil carcinoma. Life threatening intraoral bleeding resulted from the erosion of branches of the external carotid artery. After management of the bleeding, massive blood transfusions and restoration of the patient's general condition, a sandwich patch cover of the transmural pharyngeal defect was achieved using a microvascular lateral arm flap. This aimed at preventing further digestive effects and bacterial colonisation of the neurovascular structures at the carotid triangle. Unfortunately, due to external mechanical forces, the flap became avascular and thus necrotic at the eighth postoperative day; however, until the successful replacement by a myocutaneous latissimus dorsi flap it remained water-tight and fulfilled its sealing task.

Anastomosis, Surgical↗
PubMed2003

Reliability of the variables in a new set of models that predict outcome after stroke.

OBJECTIVES: To provide valid predictions of outcome, the variables included in a prognostic model must be capable of reliable collection. The authors have recently reported a set of simple but rigorously developed models that predict outcome after stroke. The aim of this study was to establish the inter-rater reliability of the variables included in the models. METHODS: Inter-rater agreement was measured prospectively (between two clinicians; 92 patients) and retrospectively (between two auditors; 200 patients) and the validity of the data collected retrospectively was estimated by comparing them with data collected prospectively (195 patients). In the prospective study inter-rater agreement for urinary incontinence and for the variables of three other previously published models was also measured. The median difference (md) between ages and kappa statistics for other variables was calculated. RESULTS: For the model variables, prospective agreement ranged from good to excellent (age: md 0 years; living alone before the stroke kappa 0.84; pre-stroke functional independence kappa 0.67; normal verbal Glasgow Coma Scale score kappa 0.79; ability to lift both arms against gravity kappa 0.97; ability to walk unaided kappa 0.91) while retrospective agreement (age: md 0 years; kappa 0.55-0.92) and agreement between prospective and retrospective observers (age: md 0 years; kappa 0.49-0.78) was acceptable but less good. Prospective agreement was excellent for urinary incontinence (kappa 0.87) and variable for the other models (kappa 0.23-0.81) CONCLUSION: The variables included in these new simple models of outcome after stroke are capable of reliable collection, comparable to or better than that of the other predictive variables considered. When collected retrospectively, the model variables are likely to remain reliable and reasonably valid.

Aged↗
PubMed2001

[Viability monitor of free flaps in hypopharynx reconstruction].

Single-stage microvascular reconstruction of neck defects with jejunum or other free flaps are well established methods. However, these flaps usually are buried subcutaneously and viability surveillance is difficult. Alternatively to technical monitoring devices, we present a simple method using a "sentinel" part of the free jejunum flap transposed outside to the skin surface or sutured into the skin when using fasciocutaneous or myocutaneous flaps. Although this method is not new, it is rarely used. Compared to pure technical monitoring devices, it is easily performed and monitoring of buried free flaps especially in the neck region is reliable.

Esophageal Neoplasms↗
PubMed2001

Enhanced fungicidal activity of N-chlorotaurine in nasal secretion.

The antifungal activity of N-chlorotaurine (NCT), a long-lived oxidant produced by stimulated human leucocytes, was investigated. Incubation of Aspergillus spp., Candida spp., Fusarium spp., Penicillium spp. and Alternaria spp. in 1% NCT (55 mM) for 1-4 h produced a log10 reduction in cfu of between 1 and 4. In samples of nasal secretion, killing was significantly hastened (30 min), which may be explained by the formation of monochloramine by halogenation of ammonium, which was found at a concentration of 1 mM in these samples. For these reasons, NCT is of interest as a new agent for treatment of local inflammatory mycosis, e.g. eosinophilic fungal rhinosinusitis.

Antifungal Agents↗
PubMed1999

One-stage reconstruction of defects in the hypopharyngeal region with free flaps.

Despite the almost universal poor prognosis, the reconstruction of combined cervical skin and hypopharyngeal defects after extensive resection of tumour should maintain optimal quality of life. From 1992 to 1996 we treated 10 patients with combined skin and hypopharyngeal defects with five fasciocutaneous free flaps, three myocutaneous latissimus dorsi free flaps, one myocutaneous VRAM (vertical rectus abdominis muscle) free flap and one free radial forearm flap. None of our flaps failed. The complications that required revision (one arterial bleeding, one arterial thrombosis, two fistula formations, one superficial wound dehiscence, one haematoma) occurred mainly in those patients having secondary reconstructions. After primary extensive oncological resection of these tumours reconstruction should be done in one stage. The primary reconstruction should provide sufficient pharyngeal lining, a satisfactory covering of cervical soft-tissue, and adequate functional rehabilitation. We have reviewed our experience and conclusions about the advantages, disadvantages, and current indications for different free flaps in the reconstruction of combined hypopharyngeal, cervico-oesophageal, and cervical skin defects.

Adult↗
PubMed1998

[3D navigation for interstitial stereotaxic brachytherapy].

AIM: The aim of this paper is to describe the adaption of 3D-navigation for interstitial brachytherapy. The new method leads to prospective and therefore improved planning of the therapy (position of the needle and dose distribution) and to the possibility of a virtual simulation (control if vessels or nerves are on the pathway of the needle). MATERIAL AND METHODS: The EasyGuide Neuro navigation system (Philips) was adapted in the way, that needles for interstitial brachytherapy were made connectable to the pointer and correctly displayed on the screen. To determine the positioning accuracy, several attempts were performed to hit defined targets on phantoms. Two methods were used: "free navigation", where the needle was under control of the navigation system, and the "guided navigation" where an aligned template was used additionally to lead the needle to the target. In addition a mask system was tested, whether it met the requirements of stable and reproducible positioning. The potential of applying this method in clinical practice was tested with an anatomical specimen. RESULTS: About 91% of all attempts lied within 5 mm. There were even better results on the more rigid table (94% < 4 mm). No difference could be seen between both application methods ("free navigation" and "navigation with template"), they showed the same accuracy. CONCLUSIONS: The accuracy of the phantom experiments and the confirmation by the experiment with the anatomical specimen showed that excellent results can be expected in clinical practice using rigid tables and patient supporting systems.

Brachytherapy↗
PubMed1998

Reconstruction of a complex hypopharyngeal cervical defect with a single latissimus dorsi free flap.

Large, complex hypopharyngeal defects that include mucosa and cervical skin, and that result from debridement of orocutaneous fistulas secondary to failed repairs of laryngectomy defects, are difficult to treat, especially when previous irradiation has damaged adjacent tissues. We have found that such defects can be repaired sufficiently in one stage using a latissimus dorsi musculocutaneous free flap. The wound is debrided until only healthy tissue remains. The skin paddle of the free flap is then used to reconstruct the hypopharyngeal mucosal defect, whereas the muscular portion serves to cover any cervical tissue that remains exposed. A split-thickness skin graft is then placed over the muscle to complete the repair. The resulting reconstruction is free of excess bulk, has no radiation damage, is well vascularized, and has an acceptable appearance.

Adult↗
PubMed1998

Altered expression of immune-related antigens by neuronophages does not improve neuronal survival after severe lesion of the facial nerve in rats.

Injection of Fluoro-Gold (FG) into the whiskerpad muscles of rats yields a permanent retrograde labeling of motoneurons in the facial nucleus. Following subsequent resection of 10 mm of the facial nerve, one-third of the facial motoneurons die and the microglia phagocytize the dead FG-labeled neurons, take up FG, and get labeled in vivo. The resulting identification of all FG-labeled cells allows long-term comparative investigations on the behavior of neuronophages. In this study, we used two groups of rats to test whether the quantified expression of five immune-related antigens by neuronophages was related to quantified decline in neuron number (counts after immunostaining for neuron-specific enolase) 3 to 224 days after resection of the facial nerve. Rats of the first group received standard food and those of the second group, pellets containing 1,000 ppm of the calcium channel blocker nimodipine. Image analysis of the number of FG-containing cells and the number and projection area of immunopositive neuronophages in serial sections for each antigen showed that nimodipine significantly attenuated the immunostaining for CR3, MHC class I, and class II antigens (monoclonal antibodies [MAbs] OX-42, OX-18, and OX-6); enhanced the expression of monocyte-macrophage-specific antigen (MAb ED1); and did not change the expression of rat macrophage differentiation antigen (MAb ED2). The altered expressions, however, had no effect on the loss of motoneurons in the lesioned facial nucleus. We conclude that the degree of expression of immune-related antigens by neuronophages has no influence on the delayed neuronal cell death induced by permanent target deprivation.

Animals↗
PubMed1997

Expression profile of stress proteins, intermediate filaments, and adhesion molecules in experimentally denervated and reinnervated rat facial muscle.

The immunohistochemical profiles of ubiquitin, heat shock protein 70, alpha-B-crystallin, desmin, vimentin, neural cell adhesion molecule (N-CAM), and tenascin in rat facial muscle were studied after permanent denervation by transection of the facial plexus on one side and compared with findings after immediate reinnervation by hypoglossal-facial nerve anastomosis subsequent to transection on the contralateral side. Levator labii muscle samples were collected sequentially at 2, 6, 7, 10, 20, and 24 weeks after surgery. Normal levator labii muscle fibers showed physiological expression of desmin and alpha-B-crystallin. Denervated rat facial muscle displayed distinct up-regulation of ubiquitin, alpha-B-crystallin, N-CAM, and tenascin. While alpha-B-crystallin and N-CAM decreased in long-standing denervation, tenascin had completely disappeared at 6 weeks. Like-wise, reinnervated muscles displayed enhanced expression of ubiquitin, alpha-B-crystallin, N-CAM, tenascin, and, additionally, desmin. Strong expression of desmin and ubiquitin was found up to the 10th week as well as of alpha-B-crystallin, N-CAM, and tenascin up to the 7th week of reinnervation. Afterward, expression of stress proteins, intermediate filaments, and adhesion molecules returned to expression profiles of normal controls, indicating that enhancement of these proteins was restricted to the "atrophic and regenerative" states with a decline to physiological levels after successful reinnervation and restoration of muscle fibers. Furthermore part of regeneration from damage seems to resemble reactivated developmental mechanisms by reappearance of developmentally expressed proteins like desmin, N-CAM, and tenascin.

Anastomosis, Surgical↗
PubMed1997

Expression of different isoforms of nitric oxide synthase in experimentally denervated and reinnervated skeletal muscle.

Denervated muscle fibers express enhanced levels of stress and apoptosis-associated proteins and undergo apoptosis. In experimentally denervated and reinnervated rat facial muscle, we now evaluate changes in the expression patterns of different isoforms of nitric oxide synthase (NOS)-generating nitric oxide (NO), which mediates oxidative stress and apoptosis. Physiological expression of NOS corresponds to a constant sarcolemmal staining pattern for neuronal NOS (nNOS) and a patchy sarcolemmal and weak sarcoplasmic labeling for the endothelial NOS-isoform, with no expression for inducible NOS (iNOS). Denervated muscle displayed distinct downregulation of nNOS with preserved expression of dystrophin. Also, denervated and immediately reinnervated muscle fibers showed decreased expression of nNOS. However, muscle fibers reinnervated for 10 weeks revealed a restored physiological expression of nNOS. There were no changes in the expression of endothelial and inducible NOS. As NO is known to induce growth arrest and collapse of neuronal growth cones, downregulation of NOS may contribute to promotion of axonal regeneration by aiding formation of new endplates. NO is upregulated in reinnervated muscle fibers and thus prevents polyneural hyperinnervation by extrajunctional synapses. Furthermore, downregulation of NOS during denervation is compatible with the finding that low levels of NO contribute to apoptosis instead of necrosis in disease states of oxidative stress.

Animals↗
PubMed1997

DNA-fragmentation and expression of apoptosis-related proteins in experimentally denervated and reinnervated rat facial muscle.

Muscle fibres may undergo apoptotic cell death in several neuromuscular disorders such as denervated muscle fibres in spinal muscular atrophies. We investigated DNA-fragmentation (in situ by the TUNEL-method) and expression of apoptosis-associated proteins in experimentally denervated and reinnervated rat facial muscle up to 24 weeks after surgery to evaluate the rate and time lapse of apoptotic muscle fibre loss. While denervated muscle displayed constantly high rates of DNA-fragmentation, denervated and immediately reinnervated muscle showed a distinct decrease of primarily elevated DNA-cleavage, finally resembling rates of normal controls. Denervated muscle fibres revealed strong immunoreactivity of the anti-apoptotic proteins bcl-2 and bcl-xL, and the pro-apoptotic factor bax. In reinnervated muscle fibres, only bcl-2 was constantly upregulated while bcl-xL and bax diminished after the 7th week. The present findings indicate that denervation may prompt muscle fibres to activate an intrinsic 'suicide' programme to undergo apoptosis. High levels of bcl-2 after denervation may sustain cell survival until reinnervation, e.g. after accidental nerve damage or in neurodegenerative disorders. Furthermore, increasing levels of bcl-2 are able to neutralize high apoptosis-promoting bax levels. Interventions modifying DNA-fragmentation and the expression of apoptosis-related proteins may lead to new therapeutic concepts in denervating disorders of muscle in the absence of other primary therapies.

Animals↗
PubMed1996

Changes in eye blink responses following hypoglossal-facial anastomosis in the cat: evidence of adult mammal motoneuron unadaptability to new motor tasks.

Hypoglossal-facial anastomosis is used in humans to restore the activity of the mimic musculature following irrecoverable facial nerve lesions. As eyelid movement kinetics is very well known, we have used this experimental model in cats to follow the evolution of blink responses and the adaptability of hypoglossal motor pools to new motor tasks. Although the electromyographic activity of the orbicularis oculi muscle in response to corneal air puffs, flashes of light or electrical stimulation of the supraorbital nerve was not recovered in the seven months following this crossed anastomosis, reflex blinks were got back by the increased activity of the retractor bulbi and extraocular recti muscles. The lid of the anastomosed side oscillated in perfect synchronization with tongue movements during licking, while it was severely affected in its motor function during optokinetic stimulation because of the spontaneous appearance of tongue-related hypoglossal activity. Present results suggest that adult mammal motoneurons are unable to readapt their motor programs to the kinetic needs of new motor targets and that most of the functional recovery observed in the cat was achieved by the compensatory hyperactivity of motor systems not directly affected by the surgery.

Adaptation, Physiological↗
PubMed1996

[Using a rotating suction debridement instrument with power generator in endonasal paranasal sinus surgery].

Endonasal nasal and sinus surgery using an endoscope for visual control has minimized the risks of surgery. A new technique is presented in which a suction-irrigation endoscope is used for visual control during surgery. The instrument is combined with a suction-rotation microdebrider with different tips and a power generator. The handling of this instrument is easy and atraumatic and it achieves a relatively bloodless field to reduce further the risk of inadvertent penetration of the skull base and lamina papyracea during endoscopic surgery.

Debridement↗
PubMed1995

Phagocytic microglia during delayed neuronal loss in the facial nucleus of the rat: time course of the neuronofugal migration of brain macrophages.

The injection of Fluoro-Gold (FG) into the whisker pad of rats yields a stable fluorescent labeling of the motoneurons in the lateral facial subnucleus. Following resection of 8-10 mm of the facial nerve, the microglia phagocytose the FG-preloaded neurons and assume the label. Employing this vital labeling of microglia in situ we studied the fate of same after completion of phagocytic activity. Starting at 56 days post resection (DPR) the FG-labeled microglia spread out from the lateral facial subdivision and invaded the entire facial nucleus. The quantitative analysis of this redistribution of the fluorescent marker revealed a prolonged increase in the number of labeled microglia strictly proportional to the delayed loss of neurons. The differentiation between microglia and shrunken neurons was performed with the new method of immunoquenching: the staining of vibratome sections with anti-rat neuron-specific enolase (NSE) combined with an ABC-HRP kit and DAB as detector totally extinguished (quenched) all fluorescence from the pre-labeled facial motoneurons. The fluorescent microglia were additionally stained with GSA I-B4 and OX-42, which should completely quench all fluorescence in the section. However, a few small round cells, always closely opposed to neuronal perikarya, still fluoresced. These NSE-negative, GSA I-B4 and OX-42 negative, but fluorescent cells may represent a new, immunologically uncharacterized microglial cell type, that participates in neuronophagia.

Animals↗
PubMed1994

Morphology of experimentally denervated and reinnervated rat facial muscle. I. Histochemical and histological findings.

The morphological changes in rat facial muscles were evaluated after permanent denervation and were compared with findings after immediate reinnervation. Thirty rats underwent transection of the left and right facial nerves immediately followed by hypoglossal-facial nerve anastomosis on the right side (muscular reinnervation) and removal of 8-10 mm of the facial plexus on the left side (permanent muscular denervation). Levator labii muscle samples of both sides were collected sequentially at 2, 6, 7, 10, 20, and 24 weeks after surgery and submitted to routine histological and enzyme histochemical staining procedures. In normal levator labii muscles a typical "chessboard" pattern was found, with type I fibers being smaller than type II fibers. These latter fibers also were more prevalent than the type I fibers. Among the type II fiber subtypes, the type IIB fibers were larger and more frequent. Two weeks after surgery, there were no differences between denervated facial muscles and those undergoing reinnervation. Both showed atrophic myofibers among normal-sized fibers and slight fibrosis. Those muscles denervated for more than 2 weeks displayed increasing fiber atrophy with frequent loss of typability, as well as proliferation of connective tissue and fat cells in perimysial and endomysial sites. After denervation for 20 weeks only a few atrophic fibers were found in wide areas of fibrosis and fat cells. Following nerve anastomosis the reinnervated levator labii muscle showed much less fiber atrophy. Regrowth to normal fiber diameters was found with only a few atrophic myofibers 10 weeks after anastomosis although a moderate fibrosis predominated at perimysial sites.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Triphosphatases↗