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N Pallua

Publications and source records attributed to N Pallua.

At least 55 records · Page 3Linked to original sources
PubMed2001

Human preadipocytes seeded on freeze-dried collagen scaffolds investigated in vitro and in vivo.

Currently, there is no adequate implant material for the correction of soft tissue defects such as after extensive deep burns, after tumor resection and in hereditary and congenital defects (e.g. Romberg's disease, Poland syndrome). The autologous transplantation of mature adipose tissue has poor results. In this study human preadipocytes of young adults were isolated and cultured. 10(6) preadipocytes were seeded onto collagen sponges with uniform 40 microm pore size and regular lamellar structure and implanted into immunodeficient mice. Collagen sponges without preadipocytes were used in the controls. Macroscopical impression, weight, thickness, histology, immunohistochemistry (scaffold structure, cellularity, penetration depth of the seeded cells) and ultrastructure were assessed after 24 h in vitro and after explantation at 3 and 8 weeks. Preadipocytes penetrated the scaffolds 24 h after seeding at a depth of 299+/-55 microm before implantation. Macroscopically after 3 and 8 weeks in vivo layers of adipose tissue accompanied by new vessels were found on all preadipocyte/collagen grafts. The control grafts appeared unchanged without vessel ingrowth. There was a significant weight loss of all grafts between 24 h in vitro and 3 weeks in vivo (p < 0.05), whereas there was only a slight weight reduction from week 3 to 8. The thickness decreased in the first 3 weeks (p < 0.05) in all grafts. The preadipocyte/collagen grafts were thinner but had a higher weight than the controls at this point in time. The histology showed adipose tissue and a rich vascularisation adherent to the scaffolds under a capsule. The control sponges contained only few cells and a capsule but no adipose tissue. Human-vimentin positive cells were found in all preadipocyte/collagen grafts but not in the controls, penetrating 1188+/-498 microm (3 weeks) and 1433+/-685 microm (8 weeks). Ultrastructural analysis showed complete in vivo differentiation of viable adipocytes in the sponge seeded with preadipocytes. Formation of extracellular matrix was more pronounced in the preadipocyte/collagen grafts. The transplantation of isolated and cultured preadipocytes within a standardised collagen matrix resulted in well-vascularised adipose-like tissue. It is assumed that a pore size greater than 40 microm is required, as preadipocytes enlarge during differentiation due to incorporation of lipids.

Adipocytes↗
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

Cross-linking by 1-ethyl-3- (3-dimethylaminopropyl)-carbodiimide (EDC) of a collagen/elastin membrane meant to be used as a dermal substitute: effects on physical, biochemical and biological features in vitro.

Next to in vitro-cultured autogeneic keratinocytes for the restoration of epidermis, a suitable dermal matrix is a mandatory component of an artificial skin substitute for the permanent covering of full thickness skin defects. In our model a xenogeneic membrane, consisting of processed native collagen and elastin of porcine origin is meant to serve as a template for the formation of a neo-dermis. In order to improve the resistance of this matrix against enzymatical degradation, we cross-linked it by using the carbodiimide 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide (EDC) together with N-hydroxysuccinimide. Chemical cross-linking by these agents at two different degrees (shrinkage temperatures 63 degrees C and 81 degrees C) had no relevant effect on mechanical features or water-uptake capacity. The time needed for enzymatic digestion was increased by cross-linking. Concerning growth and spreading of fibroblasts and keratinocytes on and within the structure of this membrane, we did not observe a difference between cross-linked and non-cross-linked material (shrinkage temperature 48 degrees C). We therefore expect that cross-linking by EDC is an effective means to control the degradation of the collagen/elastin membranes in vivo without a significant influence on their biocompatibility.

Journal Article↗
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↗
PubMed2001

Two-year histological outcome of facial lipofilling.

Although there are numerous clinical reports relating to the injection of adipose tissue fragments, only few histological assessments of the histology of these grafts in late follow-up have been made. The authors report a case of adipose tissue harvested with a sharp cannula using low-pressure suction and injection in the lower eyelid areas with subsequent sagging of the graft, although maintenance of volume, after 2 years. The operative corrective procedure consisted of a lower blepharoplasty and removal of the sheathed graft. Histology showed extended oil cysts and a surrounding capsulelike structure. The volume of the graft consisted mainly of oil cysts, and not healthy adipose tissue. The conclusion is that the harvesting procedure damages fragile adipocytes. The outcome of adipose tissue injection thus remains unpredictable. The only reliable guarantee for a good long-term outcome after lipofilling is a specimen biopsy showing healthy adipose tissue.

Adipose Tissue↗
PubMed2001

Influence of different biodegradable carriers on the in vivo behavior of human adipose precursor cells.

The correction of soft-tissue defects presents a challenge in plastic and reconstructive surgery. The implantation of isolated and culture-expanded adipose precursor cells is a solution to this problem because these cells differentiate into adipocytes when implanted in vivo. Appropriate scaffolds are needed in soft-tissue engineering to allow the differentiation of precursor cells. The optimal carrier needs to be defined. In this study, human preadipocytes were isolated and cultured. Three different carrier materials were seeded with 106 preadipocytes each and implanted in 42 nude mice. Sponges and nonwoven carriers based on hyaluronic acid modified by esterification (HYAFF 11) were compared with collagen sponges. Scaffolds without cells served as negative controls in the same animal. After 3 and 8 weeks, the grafts were explanted. Macroscopic appearance, weight, thickness, microscopy, immunohistochemistry, and TEM (scaffold structure, cellularity, penetration depth of the seeded cells, vascularization) were assessed and evaluated for differences in scaffold-cell interactions.Preadipocytes differentiated earlier in vitro when attached to HYAFF 11 scaffolds than to other carrier materials. Macroscopically, all preadipocyte constructs were yellowish and well vascularized, and the controls were white and avascular. Vessel formation was more pronounced around mature adipocytes. Microscopically, HYAFF 11 constructs showed a higher cell density than collagen constructs. The pores of the sponges contained more differentiated adipocytes than the nonwoven carriers, whereas the undifferentiated preadipocytes were more numerous in the nonwoven material. Penetration of adipose precursor cells was deeper and more homogeneous in HYAFF 11 scaffolds. Electron microscopy demonstrated well-differentiated adipocytes and large amounts of extracellular matrix in HYAFF 11 sponges.HYAFF 11 sponges supported the expansion and differentiation of the adipose precursor cells. This carrier is superior to the nonwoven carrier with regard to adipocyte differentiation and superior to the collagen sponge with regard to cellularity. This is a promising method for the reconstruction of soft-tissue defects. Modifications of the scaffold (larger pore size and coating with adipogenic factors) will be examined in further experiments.

Adipocytes↗
PubMed2000

Neutrophil intracellular pH and phagocytosis after thermal trauma.

Severe burn trauma induces an acquired dysfunction of neutrophil granulocytes. As neutrophil function is considerably influenced by intracellular pH (pH(i)), the pH(i) of blood neutrophils was longitudinally determined in 19 patients with major burns. pH(i) was measured by a flow cytometric method using the pH-sensitive fluoroprobe carboxy-semi-naphthorhodafluor-1; mechanisms influencing the pH(i) were examined by addition of amiloride (inhibition of Na(+)/H(+) countertransport), diphenylene iodonium (inhibition of NADPH oxidase) and N-formyl-methionyl-leucyl-phenylalanine (activation of H(+) extrusion). The neutrophil phagocytic activity was measured in parallel. Patients showed distinct alterations of neutrophil pH(i), depending on whether they developed sepsis in the postburn period or not. In the sepsis patients pH(i) did not deviate from the values found in healthy volunteers in the first days after injury, but rose afterwards, with significant intracellular alkalinization in the second postburn week (P<0.05). In contrast, patients without sepsis had increased pH(i) in the first (P<0.01 at days 1-2), but not in the second week after burn trauma. Inhibition studies showed that postburn intracellular alkalinization is not solely caused by activation of Na(+)/H(+) countertransport. A clear relation between pH(i) changes and phagocytosis could not be established.

Adolescent↗
PubMed2000

C1 inhibitor prevents capillary leakage after thermal trauma.

OBJECTIVE: In burned patients, activation of the complement and clotting systems is suggested to play an important role in the development of the capillary leak syndrome and inflammatory tissue destruction. In an animal model of thermal trauma, the possible protective effect of C1 inhibitor (C1Inh), a major control protein of both the complement and clotting systems, was investigated. DESIGN: Prospective, controlled study. SETTING: Animal model. SUBJECTS: Healthy pigs weighing 30 kg. INTERVENTIONS: Pigs were scalded for 25 secs with 75 degrees C hot water to achieve a 30% total body surface deep partial-thickness burn. The treatment group (n = 8) received C1Inh concentrate at an initial dose of 100 units/kg body weight immediately after thermal trauma, followed by three further applications every 12 hrs. Two control groups included animals that were either scalded (n = 8) or not scalded (n = 7) and treated with lactated Ringer's solution. MEASUREMENTS: Before and at various time points after trauma blood samples were analyzed for complement activation (APH50, CH50, SC5b-9, C3). Continuous monitoring of hemodynamic variables was performed and postmortem histologic examination of specimens from lung, heart, liver, kidney, stomach, duodenum, jejunum, ileum, and colon was carried out. Aseptically collected mesenteric lymph nodes were pooled and screened for bacterial translocation. For evaluation of the burn wound, biopsies from defined scalded and not scalded areas were taken daily. As a measure for edema formation, the weight of the animals was recorded every 2 hrs. RESULTS: After C1Inh treatment, which led to a significantly reduced complement activation, the clinical outcome was clearly improved, as indicated by vital signs and as demonstrated by reduced edema formation. Treated animals presented a diminished bacterial translocation. Pathologic alterations were clearly diminished in the burned skin, in shock-related organs, and in the intestines. CONCLUSION: Application of C1Inh appears to be an effective means to prevent capillary leakage and inflammatory tissue destruction after thermal trauma.

Animals↗
PubMed2000

The tunneled supraclavicular island flap: an optimized technique for head and neck reconstruction.

Reconstructive procedures in the head and neck region use a wide range of flaps for defect closure. The methods range from local, mostly myocutaneous flaps and skin grafts to free microsurgical flaps. To ensure a satisfactory functional and aesthetic result, good texture and color of the flap are always essential. Moreover, the donor-site defect needs to be reduced, with no resulting functional or aesthetic impairment. We have found that the shoulder is a region providing an optimum skin texture match to the neck and face. In cadaver dissection, a vascular pedicle extending from the transversal cervical artery with two accompanying veins was found to vascularize a defined region around the shoulder cap. In line with these findings, the previously described fasciocutaneous island flap, nourished by the supraclavicular artery, was developed further and used purely as a subcutaneously tunneled island flap. The tunneling maneuver significantly improves the donor site by reducing scarring. The flap is characterized by a long subcutaneous pedicle of up to 20 cm. The pivot point is in the supraclavicular region and allows the flap to be used in the upper chest, neck, chin, and cheek. In this article, we introduce the anatomic features and present clinical cases underlining the surgical possibilities of the flap in reconstructive procedures with expanded indications.

Adolescent↗
PubMed2000

Forefoot reconstruction by reversed island flaps in diabetic patients.

Soft-tissue coverage of the foot is often difficult, especially when the distal third of the foot (dorsal or plantar aspects) is involved. The clinical situation can be further complicated when diabetic patients are affected by painful and unstable wounds of this kind because of the familiar phenomenon of vasculopathy. The purpose of this study was to evaluate the possibility of using distally based foot flaps to cover forefoot defects in diabetic patients. Preoperative selection of patients was the key to this study; those who had other major disease, chronic infection, bone involvement, and/or insufficient foot vascularization were excluded from the study. The authors report a series of 12 diabetic patients in whom the reconstruction of medium-sized defects (ranging from 1.5 x 2.0 cm to 3.0 x 7.0 cm) of the forefoot was performed using distally based dorsalis pedis flaps or medial plantar flaps. The transferred flaps survived and adapted well to the defects, except for one flap in a patient who had a slight venous insufficiency at outset. Wearing their own footwear, patients could walk after 20 to 30 days. After the follow-up period (3 months to 3 years), no skin breakdown in the treated areas was observed. Temporary donor-site pain was reported by medial plantar flap patients, and partial skin graft loss at the donor site occurred in some of the dorsalis pedis patients. The authors suggest that in selected cases, medium-sized soft-tissue defects involving the dorsal aspects or the weight-bearing areas of the diabetic foot can be successfully covered with distally based island flaps.

Aged↗
PubMed1999

Combination anesthesia with ketamine and pentobarbital: a long-term porcine model.

Anesthesia of the pig poses great problems for experimental animal-based research and particularly in shock research. In this study, five mechanically ventilated domestic pigs were given long-term anesthesia with a combination of ketamine plus pentobarbital. Circulatory parameters were recorded every 2 h via an arterial catheter placed in the right common carotid artery, a Swan-Gans thermodilution catheter (7F), that was placed in the pulmonary artery of the right middle-lobe in a wedge position through the external jugular vein, and another catheter in the internal jugular vein for measuring central venous pressure. Moreover, body weight, blood gases, pH, blood cells, electrolytes and serum enzymes were measured. Further serum traits as total protein and glucose and pathological alterations in different organs were recorded. The animals were observed for a period of 96 h and then killed painlessly. It was shown that pigs can survive 96-h anesthesia with the combination of ketamine and pentobarbital. Optimum, carefully controlled anesthesia did not impair the integrity of the regulatory mechanisms of circulation.

Adjuvants, Anesthesia↗
PubMed1999

A new technique for quantitative bacterial assessment on burn wounds by modified dermabrasion.

Bacterial colonization and invasive bacterial infection is still one of the major problems in the treatment of burn victims. The standard procedures of bacterial monitoring of the burn would are i) swab-culture which is non-invasive but detects bacteria at the very surface and ii) biopsy-culture which gives a more complete view but has the disadvantage of being invasive. Therefore we developed a new technique for examination of microbial colonization of the wound surface. Dermabrasion of the upper layers of the wound was performed using a small rotating carbon-steel disc of defined roughness. The tissue samples obtained were analysed for bacterial growth in different culture media. Results were qualitatively and quantitatively compared with those of standard techniques performed in parallel. Our results show that this new technique is superior to the swab culture in identifying different bacterial species. The results can be compared with the biopsy technique, but has the advantage of being less invasive.

Adolescent↗
PubMed1999

[Neurofibroma of the palm of the hand in Recklinghausen disease. A case report].

We present a six-year-old boy with a slowly growing tumor in the palm of the left hand. Sensibility and motor function were normal, neurofibromatosis Recklinghausen had been diagnosed previously. Surgical treatment allowed macroscopically complete neurofibroma resection, but there was inflammatory infiltration of the flexor tendon sheaths and untreatable fibromatosis within the median nerve proximally.

Child↗
PubMed1999

Association between reduced human leukocyte antigen (HLA)-DR expression on blood monocytes and increased plasma level of interleukin-10 in patients with severe burns.

Severe thermal injury causes an immune dysfunction which includes a decrease of monocyte human leukocyte antigen DR (HLA-DR) expression. Interleukin-10 exerts a negative influence on this parameter in vitro. In this study we determined the prognostic value of reduced monocyte HLA-DR expression with regard to infectious complications, and the in vivo association between monocyte HLA-DR and plasma interleukin-10 concentration. Both quantities were measured serially in 19 patients with severe burns. HLA-DR expression was determined by direct immunofluorescence on a flow cytometer, and interleukin-10 was measured by ELISA. After burn trauma the percentage of HLA-DR expressing monocytes fell markedly (median: 53% at day 2, 36% at day 4, 31% at day 7, 28% at day 9, 35% at day 12, and 42% at day 14; compared to 93% for healthy volunteers). Moreover, patients who became septic showed lower monocyte HLA-DR expression than non-septic patients; the differences were significant at day 2 (p < 0.01) and day 7 (p < 0.05). Plasma concentrations of interleukin-10 increased after thermal injury (median: 40 ng/l at day 2, 43 ng/l at day 4, 77 ng/l at day 7, 120 ng/l at day 9, 63 ng/l at day 12, and 82 ng/l at day 14). Individual HLA-DR expression and interleukin-10 concentration were negatively correlated, the association reaching statistical significance at day 4 (p=0.006) and day 7 (p=0.031). Thus, after severe burn injury monocyte HLA-DR expression has prognostic value and is negatively associated with interleukin-10 plasma concentration.

Adolescent↗
PubMed1998

[Early and late treatment of iatrogenic injection damage].

Extravasation injuries can result in extensive soft-tissue defects. On the cellular level there are five different pathophysiological mechanisms. Early treatment (surgical removal of the extravasated material within 24 h) and late treatment (debridement and coverage) are different. Thirty-two patients who suffered a significant extravasation were treated surgically by the Department of Plastic Surgery between 1989 and 1997. In 8 patients, referred within the first 24 h, the extravasated material could be removed by saline flushout. None of these patients developed soft-tissue defects or skin necrosis. The other 24 patients were referred late (mean 19 days after the injury). Patients with defects of the dorsum of the hand or cubital fossa area who underwent debridement, temporary wound coverage and skin grafting (n = 11) presented complete healing 52 days after the referral. Defects of the same regions covered by a flap after debridement (n = 6) healed within 14 days. The healing time of defects of the forearm (n = 2) and dorsum of the foot (n = 5) was a mean of 15 days after skin grafting. Cytotoxic and osmotically active substances should be removed by saline flushout within 24 h. In defects of the dorsum of the hand and cubital fossa, early debridement and coverage with an adequate flap should be performed.

Adolescent↗