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Biomedical subjects

E M Noah

Publications and source records attributed to E M Noah.

At least 19 recordsLinked to original sources
PubMed2006

Enhancing angiogenesis in collagen matrices by covalent incorporation of VEGF.

Since the survival of ingrowing cells in biomaterials for regenerative processes largely depends on the supply of nutrients and oxygen, angiogenesis plays an important role in the development of new materials for tissue engineering. In this study we investigated the possibility of enhancing the angiogenic properties of collagen matrices by covalent incorporation of the vascular endothelial growth factor (VEGF). In a previous paper we already reported the use of homo- and heterobifunctional cross-linking agents for modifying collagen matrices [1]. In the present work the angiogenic growth factor was linked to the collagen with the homobifunctional cross-linker disuccinimidyldisuccinatepolyethyleneglycol (SS-PEG-SS) in a two step procedure. The efficiency of the first reaction step-the reaction of SS-PEG-SS with VEGF--was evaluated by western blot analysis. After 10 minutes virtually all of the dimeric molecules VEGF were on average modified by conjugation with 1 cross-linking molecule. The biological activity of the conjugate was investigated by exposing endothelial cells to non-modified VEGF and to VEGF conjugated to the cross-linker. The conjugation only had a limited effect on the mitogenic activity of VEGF. We therefore applied the cross-linking reaction to the VEGF-collagen system. In a first approach the changes were evaluated by the in vitro exposure of HUVECs to non-modified matrices, to matrices in which the VEGF was simply admixed and to matrices in which the VEGF was covalently incorporated. The angiogenic properties were evaluated in vivo with the chorioallantois membrane model. In this assay the chorioallantois membrane of the chicken embryo was exposed to the same set of matrices. The covalent incorporation of VEGF has a small but significant effect both on the formation of microvessels in the chorioallantois membrane and the tissue ingrowth into the implant. The covalent incorporation of angiogenic growth factors may thus be considered as a promising approach for enhancing the angiogenic capabilities of collagen matrices. Also the cross-linking with the homobifunctional cross-linking agent has a positive effect on the angiogenic potential of the collagen matrices.

Animals↗
PubMed2005

The use of Integra in an upper extremity avulsion injury.

We present the case of a 22-year-old man who suffered an avulsion injury of the left upper extremity including the elbow region in an industrial accident. After debridement of the skin flap, the defect was primarily closed with Integra. On day 22 split thickness skin graft was performed. Functional and aesthetic outcome and skin quality are excellent.

Accidents, Occupational↗
PubMed2004

Update on the use of collagen/glycosaminoglycate skin substitute-six years of experiences with artificial skin in 15 German burn centers.

The clinical use of an artificial skin substitute (Integra) has been celebrated enthusiastically as an improvement in burn therapy over a period of more than 10 years. Many case-reports have shown the positive effects of the treatment with Integra as a skin substitute. In this study we examine the alterations of Integra-usage in Germany. Fifteen German burn centres have been interviewed respectively over a time period of 6 years with interviews in the years 1999, 2001, and 2003. The goal of this study is to focus on the problems associated with the use of artificial skin and to create a manual for Integra-therapy including indication, pre-, intra-, and postoperative treatment. Since the first Integra Users seminar in Germany in 1999 repeated interviews have been conducted with fifteen German burn centres. The collected results of the last 6 years were evaluated. These results show a change in the indication for the therapy with artificial skin towards extensive full thickness burned patients and as extended indication especially for posttraumatic reconstruction. This article gives our guidelines for the usage and handling of Integra and shows that Integra is an important reconstructive dermal substitute for the severely burned or posttraumatic patient if handled by a skilled surgeon in a correct way.

Anti-Infective Agents, Local↗
PubMed2003

Psychosocial adjustments 5 years after burn injury.

The present study investigates factors influencing the quality of life and social reintegration of burn victims. A study concept was developed to assess the functional and aesthetic long-term outcomes of burn victims. Objective data from a clinical examination was correlated with subjective data from completed questionnaires. The success of social rehabilitation was documented and an indicative profile of life quality evaluated. This profile could prompt early intervention if found necessary. Ninety-two patients were examined 5.4+/-1.1 years after trauma in relation to three factors: physical functions, localization of the burn injuries and extent of the body surface area burned. Physical functioning allows the best predictions for successful rehabilitation, because all areas of life quality are affected by it. Localization of burns in the face and hands creates disadvantages in social reintegration. Of less value in prediction is the extent of the body surface area burned, which is only closely linked to occupational rehabilitation and directly correlates to physical functional limitations. Our correlation showed, that even slight functional limitations were linked to severe depressions, similar to the values found with patients with serious functional impairment. Interdisciplinary cooperation between plastic surgeons and psychosomatic specialists will optimize early intervention with patients exposed to social maladaptation.

Adaptation, Psychological↗
PubMed2003

[A rare case of cannabis arteritis].

A 24-year old woman, heavy cannabis smoker with progressive Raynauld's phenomenon and digital necrosis is presented. Systemic sclerosis and other connective tissue disorders as well as arteriosclerosis and arterial emboli were excluded with appropriate laboratory examinations. Arteriography revealed multiple forearm, palmar and digital occlusions with corkscrew-shaped vessels. Based on these characteristic arteriography and clinical findings, the diagnosis of cannabis-arteritis was finally retained. With careful necrectomy, conservative wound dressings and secondary prostacyclin therapy a complete healing of digital necrosis was observed. There was no recurrence during the 6 month-follow-up. This observation demonstrates that cannabis may represent a possible cofactor in the pathogenesis of arteritis in young smokers. Early recognition is important to avoid irreversible complications such as loss of digits.

Adult↗
PubMed2002

Impact of innervation and exercise on muscle regeneration in neovascularized muscle grafts in rats.

The direction of known staged process of regeneration of free muscle grafts was inverted in our experimental rat model from a centripetal to a centrifugal by central implantation of blood vessels into isolated free muscle grafts. The effects of innervation, reinnervation and exercise on muscle fiber regeneration were analyzed at various intervals from 4 to 90 days by morphological and morphometric methods. Reinnervation occurred as well in grafts with the motor nerve left intact as it did in grafts with a severed and reimplanted nerve. Reinnervation proved to be prerequisite for a lasting muscle regeneration. Denervated muscle grafts even after neovascularization underwent irreversible fibrosis. A positive effect of exercise on the early states (30 days) of muscle regeneration was revealed by morphometrical analysis. In the long term (90 days) fiber diameter assimilated in all groups. The animal model mimics a clinical situation of flap prefabrication demonstrating the relationship of functional tissue regeneration and neovascularization. It can be transferred into the acute clinical situation as well as in tissue engineering.

Animals↗
PubMed2002

The use of bifunctional polyethyleneglycol derivatives for coupling of proteins to and cross-linking of collagen matrices.

The realization of three-dimensional (3D) degradable matrices which slowly release bio-active components represents a major challenge in the field of tissue engineering. In this paper we report on the usage of commercially available bifunctional agents for both the covalent coupling of proteins to and the cross-linking of collagen matrices. Proteins - horse radish peroxidase (HRP) was used as a model protein - were cross-linked with either a homobifunctional (disuccinimidyldisuccinatepolyethylene-glycol) or a heterobifunctional (N-hydroxysuccinimidylvinylsulfonepolyethyleneglycol) agent. In the case of the heterobifunctional cross-linking agent the collagen matrices were previously modified with succinimidylacetylthioacetate in order to introduce sulfhydryl groups. As compared with control experiments a 10-fold and 50-fold increase of immobilized proteins were achieved with the homobifunctional and heterobifunctional cross-linker resp. The HRP-PEG conjugates demonstrated a better long-term stability as compared to the non-treated HRP. The effects of the cross-linking agents and the thiolation reagent succinimidylacetylthio acetate on the in vitro degradation of the collagen matrices by collagenase were also investigated. In particular the reaction with succinimidylacetylthio acetate appears to offer interesting opportunities both for coupling active proteins and modulating the degradation times of collagen matrices.

Journal Article↗
PubMed2002

Extensor-tendon hypoplasia and multiple pterygia: Escobar syndrome in a 7-year-old boy.

Escobar syndrome is a rare condition with autosomal-recessive inheritance, characterised by multiple pterygia, kyphoscoliosis, multiple joint contractures and craniofacial dysmorphisms. A number of other abnormalities are also attributed to the syndrome. Here, we present a case of isolated extrinsic extensor-tendon hypoplasia of the right index finger in a 7-year-old patient with Escobar syndrome. To our knowledge, this has not been previously described in connection with this syndrome.

Abnormalities, Multiple↗
PubMed2001

Burn injuries caused by air bag deployment.

Automobile air bags have gained acceptance as an effective measure to reduce the morbidity and mortality associated with motor vehicle accidents. As more cars have become equipped with them, new problems have been encountered that are directly attributable to the deployment of the bag itself. An increasing variety of associated injuries has been reported, including minor burns. We present two automobile drivers who were involved in front-impact crashes with air bag inflation. They sustained superficial and partial-thickness burns related to the deployment. The evaluation of these cases shows mechanisms involved in burn injuries caused by the air bag system. Most of the burns are chemical and usually attributed to sodium hydroxide in the aerosol created during deployment. Also direct thermal burns from high-temperature gases or indirect injuries due to the melting of clothing, as well as friction burns from physical contact are possible. However, the inherent risks of air bag-related burns are still outweighed by the benefits of preventing potentially life-threatening injuries.

Abdomen↗
PubMed2001

Life threatening burn injuries on holidays: problems of primary care, homeland referral and treatment at a domestic burn centre.

Life threatening burn injuries during vacations abroad raise special problems. Depending on the infrastructure of the country, adequate medical care can be delayed and communication between the patient and the medical staff is frequently impossible due to language barriers. Often the patient finds himself in a critical condition, isolated from supporting relatives and financial difficulties may occur. By summarising three cases referred to our centre, we aim to emphasise particularities of the primary management of burned victims at foreign hospitals, their transport, and following therapy at a domestic burn unit. Primary shock treatment and vital surgical interventions, e.g. escharotomy or treatment of the concomitant trauma, are subject to the facility of the hosting country. After management of the acute phase and initiation of local wound treatment, the next step should be to stabilise and prepare the patient for transport. Aeromedical transportation with physician attendency, as well as contact with a domestic burn centre can be established via responsible organisations. At the domestic hospital, every burn victim from abroad deserves special attention. Wound colonisation with different bacterial species or fungi than the usual spectrum of the centre and the risk of crossinfections should be taken in account of the treating medical team. An structure plan for appropriate and continuing surgical treatment is necessary to prevent deterioration of the patient's condition and to optimise wound closure with autologous skin grafts or allogenic materials.

Adult↗
PubMed2001

Hyperbaric oxygen treatment in deep frostbite of both hands in a boy.

UNLABELLED: An 11-year-old boy in good general health conditions suffered deep frostbite on six fingers while he was working without gloves as a beater during a hunt in Poland at an outdoor temperature of -32 degrees C over a 4 h-period. Three days later he was first seen by a physician who planned to amputate the affected fingers. The patient was transferred by his family to our University Hospital in Aachen, Germany. We found third degree frostbite on four fingers of the right and on two fingers of the left hand. Because of the late beginning of the therapy, the patient was treated by HBO(2) according to the Marx-schema for problem wounds (2,4 bar, total time at depth: 90 min, alternations of 100% O(2) and air breathing). HBO(2)-treatment was repeated daily for 14 days. No adverse events were recorded during the course of therapy. A total recovery of the severe frostbite was observed after 14 days of HBO(2)-treatment. Twenty-eight months after the injury the patient reports fully regained sensibility and no pain. The plain X-ray after this period showed no premature closure of the epiphyses or sclerosis of the metaphyses. CONCLUSIONS: Because of the low risk associated with HBO(2), and its potential therapeutic efficiency, HBO(2) should be recommended as adjunct therapy in the treatment of deep frostbite.

Child↗
PubMed2001

[Plasma endotoxin, procalcitonin, C-reactive protein, and organ functions in patients with major burns].

Sepsis is one of the most frequent causes of death after major burn injury. Usually, sepsis appears as a consequence of a gram-negative bacteriaemia with release of endotoxins. In this study, the plasma endotoxin levels of seven patients (three female, four male; average age 51.3 +/- 23.8 years) with burns between 43.5 and 78 % Total Body Surface Area (Abbreviated Burn Severity Index 8 - 12) were determined for five days after thermal trauma every three hours by ELISA and compared with the concentration of procalcitonin (PCT) and C-reactive protein (CRP). A calculation of the Horrowitz-Index (PaO(2)/FiO(2)) and the Pressure-Adjusted Heart Rate (HR x CVP/MAP) took place to show a possible correlation between the endotoxin concentration and the cardiopulmonary organ function. Additionally, we analysed whether operative treatment can influence the level of plasma endotoxin in the early phase after burn injury. At any time after burn trauma, endotoxins could be detected in the plasma of all patients. Between the second and third day, there was a considerable increase in the endotoxin concentration with a maximum after 57 hours of 0.48 +/- 0.32 EU/ml. Two patients with sepsis and death in the further course had a rather distinctive increase. From the fourth day on, occasional episodes of increases in endotoxin concentration were noted. Postoperatively, there was a short increase in plasma endotoxin on the second and fourth day. The plasma endotoxin level showed no correlation with the PCT and CRP or with the oxygenation in the patients' blood. However, a positive correlation could be observed with the Pressure-Adjusted Heart Rate (p = 0.0061; r(2) = 0.212). An explanation for the endotoxin increase after 57 hours could be the translocation of intestinal bacteria, the beginning of bacterial colonisation or decomposition products of the burn wound with protein-protein complexes. Later on, infectious diseases such as pneumonia with gram-negative bacteria are of importance, too. According to the Two-Hit Model, the increase of plasma endotoxin can serve as a trigger and cause a recurrence of systemic inflammation with the changes observed in cardiac organ function, multiple organ dysfunction, and multiple organ failure.

Adult↗
PubMed1999

End-to-side neurorrhaphy: evaluation of axonal response and upregulation of IGF-I and IGF-II in a non-injury model.

This research group has introduced a model of end-to-side neurorrhaphy, in which reinnervation occurs without frank damage to donor axons. The current study used in situ hybridization to test the hypothesis that insulin-like growth factor (IGF-I and IGF-II) mRNA levels increase at the coaptation site and grafted nerve following end-to-side repair, and that this increase is associated with axonal sprouting and growth. One week after end-to-side coaptation, IGF-I mRNA was localized predominantly on the epineurial side of the graft perineurium, while IGF-II was seen mainly on the endoneurial side. IGF-I hybridization was greatest at this time and declined by 2 weeks post-procedure. No changes in IGF mRNA levels occurred in the distal donor nerve. The increase in IGF-I mRNA at 1 week preceded the appearance of myelinated axons. The presence of myelinated axons within the graft 2 weeks after end-to-side coaptation was associated with a decline in IGF-I mRNA. These data are the first to demonstrate increased IGF mRNA levels associated with axonal sprouting and growth following end-to-side neurorrhaphy. Moreover, the findings support those of earlier studies by others implicating IGFs in axonal regeneration. The increase in IGF mRNA during sprouting and axonal growth into an end-to-side coaptation indicates that the local therapeutic augmentation of endogenous IGF levels at the coaptation site may enhance axonal sprouting from a minimally injured donor nerve, and thereby increase the number of axons that reinnervate the graft.

Anastomosis, Surgical↗
PubMed1998

Intrabronchial surfactant application in cases of inhalation injury: first results from patients with severe burns and ARDS.

Damage to the respiratory tract caused by inhalation of toxic products of combustion with subsequent development of an acute respiratory distress syndrome (ARDS) is one of the main causes of death in burn patients. Treatment with an exogenous surfactant is a therapeutic option for which there has previously been no empirical data. We report on four severely burned patients with deep partial thickness and full thickness burns of between 40 and 70 per cent body surface area (BSA), and with inhalation injury complicated by ARDS. These patients were treated once or more than once with bovine surfactant replacement (Alveofact). In addition to biophysical and biochemical analysis, the influence of this substance on oxygenation and lung function were evaluated. After the limits of mechanical ventilation had been reached, bronchoscopic intrabronchial administration of surfactant was followed by temporarily improved gas exchange with an increase in arterial O2 partial pressure (PaO2), accompanied by a reduction in inspiratory O2 concentration (FiO2), and also improved lung compliance. All the patients survived in spite of an initially unfavourable prognosis. Replacement of exogenous surfactant in the treatment of inhalation traumatized severe burn patients with ARDS appears to show considerable promise as an approach to improving the survival chances of these high-risk patients.

Adolescent↗
PubMed1997

End-to-side neurorrhaphy: a histologic and morphometric study of axonal sprouting into an end-to-side nerve graft.

This study investigated axonal regeneration in a denervated nerve graft sutured end-to-side with a main peripheral nerve trunk. To demonstrate morphologic changes, the peroneal nerve was severed in a rat and coapted end-to-side to the posterior tibial nerve. The integrity of the epineurial and perineurial sheath was altered in four different groups. Histologic evaluation 30 days after operation showed axonal regeneration in the nerve graft in all groups. Morphometric analysis of cross sections of the grafted nerve elucidated the importance of severance of the perineurium in end-to-side neurorrhaphy.

Anastomosis, Surgical↗
PubMed1997

A new animal model to investigate axonal sprouting after end-to-side neurorrhaphy.

End-to-side neurorrhaphy is a technique that may provide a solution for the problem of distal target reinnervation without injury to the original donor nerve. The technique drew extensive attention after Viterbo reported his experiments in 1992; however, to date, the animal models used to elucidate the process of lateral axon sprouting had the disadvantage of substantial injury to the donor nerve, raising questions about the origin of axons reinnervating the nerve graft. In this report, a new model in the rat is introduced, in which the donor nerve is not damaged and an additional target can be innervated via a nerve graft. The saphenous nerve represents the axonal conduit; the proximal end is coapted end-to-side to the sciatic nerve at the site of a perineurial window. The distal end is passed through the adductor muscles and coapted distally in an end-to-end fashion with the obturator nerve. In one group, a partial neurectomy was performed at the site of coaptation, which led to a lower Sciatic Functional Index (SFI). In the second group, the creation of a perineurial window yielded a normal SFI after end-to-side neurorrhaphy. Compared to the partial neurectomy group, the perineurial window end-to-side neurorrhaphy resulted in significantly less axons in the graft. The new model has the following advantages: (a) minimal injury to the donor nerve; (b) provision of a single additional target (gracilis) whose functional recovery can be assessed morphologically and behaviorally; (c) an opportunity to understand lateral sprouting by providing a non-injury model in which axonal invasion of the graft can originate from nodal axonal outgrowth; and (d) establishment of a noninjury model that can have widespread clinical applications.

Anastomosis, Surgical↗