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Biomedical subjects

H H Homann

Publications and source records attributed to H H Homann.

At least 19 recordsLinked to original sources
PubMed2006

Polybrene improves transfection efficacy of recombinant replication-deficient adenovirus in cutaneous cells and burned skin.

BACKGROUND: The hostile environment found in acute and chronic wounds decreases the physiological half-life of purified synthetic or recombinant peptides dramatically. Gene therapy, on the other hand, may be a viable option since it relies on the cellular machinery of the host to locally manufacture the proteins of interest. The aim of this study was to evaluate and optimize the local administration of transient cutaneous adenoviral gene delivery in wounds. METHODS: Primary human keratinocytes (HKC) and HaCaT cells were transfected with replication-deficient adenovirus (Ad5) containing the reporter gene for beta-galactosidase (LacZ). The vector was used alone or precoated with either (1) Lipofectamine 2000, (2) FuGENE 6, or (3) Polybrene. For in vivo testing a rat burn model was used. Animals were randomized into three groups: (1) Ad5-LacZ alone; (2) Ad5-LacZ precoated with Polybrene, or (3) carrier control (phosphate-buffered saline (PBS)). Samples were harvested from burned and unburned tissue sections after either 48 h or 7 days. Transgene expression was quantified by bioluminometric assay and localized using immunohistochemistry. A BrdU assay was performed to determine the influence of the used transfection reagents on cell proliferation. RESULTS: Transfection efficacy was significantly improved in vitro (p < 0.001) as well as in partial thickness burned (p = 0.015) and unburned skin (p > 0.001) after precoating Ad5 with Polybrene compared to Ad5 alone. Transgene expression was 10-fold higher in burned skin (9305 pg/mg protein) compared to unburned skin (859 pg/mg protein). CONCLUSIONS: It is feasible to improve transfection efficacy in vitro and in vivo by precoating the adenovirus with Polybrene.

Adenoviridae↗
PubMed2005

A qualitative and quantitative analysis of protein loss in human burn wounds.

INTRODUCTION: It is well known that in patients suffering from major burn injuries of more than 15% of total body surface area (TBSA), capillary leak and loss of proteins including immunoglobulins (Ig) lead to cardiovascular failure and significantly elevated risk of infections. However, knowledge of the resulting protein profiles is limited. In order to elucidate quantitative and qualitative protein loss in human burn wounds we compared wound fluid (WF) protein content with serum protein levels. MATERIAL AND METHODS: Eleven patients suffering from second degree burns of 18-68% TBSA were enrolled in the study. Immediately after admission burn wounds were enclosed in cutaneous vinyl wound chambers covering a 2.25 cm(2) wound surface area. WF and serum samples were harvested every 8 h with a follow up of 48 h and analyzed for total protein content, albumin and the immunoglobulins A, E, G and M. RESULTS: Protein levels in serum were significantly lower as compared to physiological levels while WF protein levels were elevated and remained high. Total protein (TP) and albumin (AL) accumulated in high concentrations on the wound surface (average accumulation on 10% burnt TBSA within 8 h: TP=16.59+/-8.86 g; AL=12.39+/-5.87 g). The albumin fraction in WF showed increasing values (24 h: 69%; 32 h: 86%) although the serum albumin fraction remained nearly unchanged (55%). Peak values were initially found for all immunoglobulins both in serum and WF. IgA, E and M reached a steady state 32 h post-trauma, whereas IgG continuously decreased until 40 h. IgG values in serum were significantly below physiological levels at all time points. CONCLUSIONS: This study qualifies and quantifies a significant protein loss in second degree burn wounds. Protein concentrations in wound fluid correlate highly with serum concentrations until 48 h post-burn. A patient's entire amount of serum proteins accumulates in wound fluid in a 20% TBSA burn within approximately 24h. In contrast to capillary leak theory proteins and immunoglobulins extravasate to wound fluid even after 48 h post-trauma.

Adult↗
PubMed2005

New model for in vivo investigation after microvascular breakdown in burns: use of intravital fluorescent microscopy.

BACKGROUND: The breakdown of skin microcirculation is assumed to play a key role in the pathophysiology after burn injury. The aim of the present study was to develop a burn model, which allows repetitive quantitative in vivo analysis of the microcirculation after a burn injury, focusing on the interaction between leukocytes and the endothelium. MATERIALS AND METHODS: Experiments were carried out on male hairless mice. Deep partial thickness burns were inflicted with a no-touch-technique to the ears. Intravital fluorescent microscopy in combination with FITC-dextran as a plasma marker was used to assess microcirculatory parameters. Leukocytes were stained with rhodamine 6G. Preburn baseline data was obtained before as well as 1, 3, 7 and 14 days subsequent to the burn injury. RESULTS: The non-perfused area decreased significantly over the observed period and perfusion was almost completely restored at day 14. The functional vessel density was characterized by reduction of perfused vessels immediately after burn and an increase after 24h. Leukocyte endothelium interaction significantly increased immediately after injury; baseline values were reached 1 day later. The extravasation of the plasma marker into the surrounding tissue increased immediately after burn, decreased at day 1 and remained at this level during the following observation time. The venular as well as the arterial blood flow increased immediately subsequent to the burn injury, decreased after 1 day and reached baseline values at day 3. CONCLUSION: The presented burn model allows quantitative assessment of the dynamics of microcirculatory disturbances after thermal trauma by high quality visualization of both plasma stained microvessels and leukocyte-endothelium interaction.

Animals↗
PubMed2004

The impact of topical antiseptics on skin microcirculation.

AIM: Antiseptics are commonly used in clinical practice to disinfect tissue and to avoid infections. However, topical antiseptics are assumed to have an influence on skin microcirculation, per se. Thus, the aim of the study was to analyse the influence of topically applied antiseptics on the microcirculation of intact skin in vivo. MATERIALS AND METHODS: The investigation was carried out on ears of male hairless mice (SKH-1hr, n = 25). The influence of four antiseptics was examined. Sodium chloride 0.9% served as control. An alcohol-based solution with a mixture of ethanol, 2-propanol and purified water (Softasept), an antiseptic with octenidine dihydrochloride and phenoxyethanol as the main active agents (Octenisept), as well as hexamethylenbiguanide (Lavasept) and 70% ethanol were tested. Intravital fluorescence microscopy in combination with intravenous injection of the fluorescence dyes FITC-Dextran as plasma marker and Rhodamine 6G (leukocyte staining) allowed a quantitative analysis of standard microcirculatory parameters (vessel diameter, functional capillary density, red blood cell velocity, FITC-leakage and leukocyte endothelium interaction). Recordings of the microcirculation in several regions of interest (ROI) were made prior to application and after 10 min exposure time and 60 min after the baseline data. Data were evaluated off-line with aid of computer assisted analysis. RESULTS: The diameter of arterioles decreased after the treatment with the alcoholic solutions. The other two antiseptics (Octenisept and Lavasept) caused a significant increase. Functional capillary density (FCD) was significantly reduced after application of ethanol and Softasept. There was no reduction of FCD following application of Octenisept. After treatment with ethanol and Softasept there was a significant decrease in red blood cell velocity (RBCV). The use of Lavasept revealed a decrease of FCD and RBCV. In the Octenisept treated group RBCV shows a mild increase after 10 minutes. The application of ethanol, Softasept and Lavasept was characterized by a significant increase of leukocyte endothelium interaction (LEI). After treatment with saline and Octenisept LEI remained constant. All used antiseptics except of Octenisept caused a significant leakage of FITC-Dextran. CONCLUSION: The antiseptics used in this study all showed an influence on skin microcirculation. As expected, our findings show that the alcoholic solutions are most aggressive to skin microcirculation.

Administration, Topical↗
PubMed2004

[The interdisciplinary approach in reconstructive surgery of the extremities].

In cases of extended post-traumatic soft-tissue and bone loss as well as with mutilating infection or radical tumor resection, multidisciplinary options are required to salvage extremities and functional rehabilitation. A surgical team approach allows for reduction of amputation rates, wound healing complications, and secondary procedures in limb oncology and trauma. The goals and limitations of cooperative surgical concepts are described. In the future, continuing medical education will focus not only on indications and techniques but also on complication management, medicolegal problems, and economic deficits due to maladapted legal structures. Provided clear clinical pathways are introduced to guide indications, surgical procedures, and postoperative treatment, marked financial deficits may be avoided. While, in the past, responsibility for the patient and ethical considerations resulted in the development of voluntary interdisciplinary treatment programs, economic strategies and an increasing number of malpractice suits will inevitably produce new imperatives for interdisciplinary cooperation in the future.

Adult↗
PubMed2004

[Gorham-Stout disease: report of a case affecting the right hand with a follow-up of 24 years].

Gorham-Stout disease is a rare idiopathic syndrome with distinctive clinical, pathologic and radiologic features. It is a variant form of osseus angiomatosis associated with massive osteolysis of bone. Usually appearing after trauma, the disease is described to occur at any age. Especially in case of thoracic involvement (chylothorax), lethal outcomes are reported. In Medline, about 200 cases have been described. A patient with osteolysis of the right hand following contusion at the age of two years is reported. Despite radiotherapy and repeated bone grafting, the osteolysis progressed until today (24 years). The pathologic features and various treatment methods for hand involvement are discussed.

Adult↗
PubMed2004

[Importance of microcirculation in plastic surgery].

The article summarizes distinct microcirculatory models for use in surgical research with a special interest to plastic surgery. Methods for the quantitative analysis of the microcirculation in burns, flaps and wounds are presented. Vascularization of biomaterials can be observed by means of the dorsal skinfold chamber model in hamsters and mice. Developing capillary sprouts can be assessed by means of videomicroscopy and angiogenetic drugs can be tested using this model. Hairless mice allow for direct, long-term observation of the microcirculation in burns as well as during healing of dermal wounds. The pathophysiology of diabetic wound healing can also be studied. A mouse model to assess flap microcirculation during ischemia/reperfusion injury with special emphasis on platelet/endothelium interaction in vivo is described. Platelets adherent to the inner vessel wall are known to trigger compromised perfusion in flaps. The model allows us to test anti-thrombotic drugs. The use of a special microscopic device (OPS imaging) allows us to study the microcirculation at sites of burn injury and chronic wounds in humans. Microcirculatory research in plastic surgery has increased the understanding of the pathophysiology of vascularization of biomaterials, wound healing and ischemia/reperfusion.

Animals↗
PubMed2003

[Myofibroblastic sarcoma of the thoracic wall. Change in appearance in tumour recurrence].

The existence of malignant mesenchymal tumours with myofibroblastic differentiation (myofibroblastic sarcoma, myofibrosarcoma) is controversially discussed. In the present case report a low-grade myofibroblastic sarcoma of the thoracic wall with varying morphological appearance in numerous recurrences over a number of years is described. The varying immunophenotypes of tumour cells with myofibroblastic differentiation suggests that changing of morphological and immunohistochemical phenotypes may occur in tumour cells with myofibroblastic characteristics corresponding to the "plasticity" of the myofibroblast. The classification of soft tissue tumours is based on a discernible line of differentiation. If cells of a malignant mesenchymal tumour show characteristic features of myofibroblasts by light microscopy and immunohistochemistry, this neoplasm should be classified as a myofibroblastic sarcoma, even if the ultrastructural detection of "fibronexus" is not possible.

Antigens, Neoplasm↗
PubMed2003

[No problem with liposuction?].

Subcutaneous liposuction in tumescent technique is the most frequent aesthetic plastic procedure in the United States. In Germany, nearly 250,000 liposuctions are done per year by a variety of surgical and nonsurgical specialists including plastic surgeons, dermatologists, gynecologists, oral surgeons, and otolaryngologists in settings ranging from hospital operating rooms to physicians' offices. The method is applied and promoted as an easy-to-learn technique that is suited as an outpatient procedure. Although major complications seem to be rare, there are definite risks, including death at a rate of 1/5,000 procedures. Major risk factors are insufficient hygiene standards, multiliter wetting solution infiltration, megavolume aspiration, multiple cosmetic procedures in one setting, sedative and anesthetic drug hangover threatening ventilation, permissive postoperative discharge, and mistakes in patient selection. When major complications occur, office-based practitioners may refer patients to hospital emergency departments, where medical personnel unfamiliar with this procedure may underestimate the risk of major complications.

Adult↗
PubMed2002

[Solitary plasmacytoma of the shoulder. Diagnosis and therapeutic methods].

5% of all multiple myelomas manifest as solitary plasmocytomas. The multiple myeloma is the most frequent malignant transformation of the haematopoetic system, with an incidence of 2:100,000 per year. 1% of all solitary plasmocytomas are found in the extremities, accounting for less than one case per year in Germany. In this article we present the case of a fifty year old patient with a solitary plasmocytoma of the shoulder region and discuss the diagnostic and therapeutic procedures involved.

Diagnosis, Differential↗
PubMed2002

[Carl von Reyher's studies of wound therapy].

Carl von Reyher (1846-1890), a young Russian army surgeon of the late nineteenth century, established the principle of repeated debridements on a scientific basis. After a visit to Lister's clinic, acquainting himself with antiseptic wound management, von Reyher was the first to present a controlled study of debridement in contaminated gunshot wounds. He was able to show that the combination of primary debridement and antiseptic treatment decreased the mortality rate of gunshot injuries from 66% to 23%. Although published in more than 16 papers and presented at international congresses, Reyher's contribution was completely negated. Finally more than 30 years later in World War I, the Inter-allied Surgical Conference officially endorsed primary excision with delayed wound closure as the rule for treatment of gunshot wounds.

Antisepsis↗
PubMed2002

The effect of wound ointments on tissue microcirculation and leucocyte behaviour.

An intact microcirculation is essential for normal healing to occur. Wound repair may be impaired by various endogenous and exogenous factors, such as reduced microvascular perfusion, infection and debris. In the nonhealing wound, radical surgical debridement is critical. To supplement healing, various ointments are used in clinical practice. Little is known about their effects on tissue perfusion. We have therefore selected two substances widely used, the antiseptic Betadine and the enzyme combination Elase and investigated their impact on the microcirculation and on leucocyte activity, using the cremaster muscle as a model. We found that functional capillary density and arteriolar diameters were significantly reduced by Betadine, whereas leucocyte activity was not affected. In the Elase group, capillary flow and arteriolar diameters were significantly increased, and again leucocyte activity was not changed. The mechanism by which Betadine reduces microvascular flow is believed to be the same as in reperfusion injury. The positive effect of Elase on the microcirculation might be attributed to plasmin, which has been shown to dilate blood vessels.

Analysis of Variance↗
PubMed2002

[Secondary reconstruction after burns of the anogenital area].

The incidence of burns of the genitalia and peri-anal region which may cause a reconstructive intervention is very low. In the most cases the use of split thickness skin grafts yields a sufficient permanent wound closure. Upcoming problems such as painful scare formation require a reconstructive intervention (Z-plasty, full thickness skin grafting, pedicled flaps etc.). In case that the anal sphincter is involved with the consequence of incontinence or major damage of the genitalia occurred, sophisticated operative solutions are necessary.

Anal Canal↗
PubMed2002

[Joint infection caused by radiogenic defect: prevention and therapeutic options].

Exposed irradiated joints are characterized by bone and cartilage necrosis with a chronically infected joint space. The indication for treatment results from possible infection spreading and more often because of severe pain. The usual concept of sequential debridement, joint replacement and regional flap coverage, is often impossible due to the radiodermitis and bone necrosis in the neighbourhood of the joint. Even free flaps are associated with a higher failure rate, because of the irradiation of the recipient vessels long vein grafts are often needed. If regional flap coverage is desired, distant flaps with long, not irradiated pedicles must be chosen. Prevention due to special considerations during the first surgery is essential.

Amputation, Surgical↗
PubMed2002

[Direct visualization of microcirculation in burn wounds with OPS imaging--is determination of depth of burns possible?].

Adjunct diagnostic techniques might help surgeons to accurately analyse the depth of a burn. However, despite all technical innovations an ideal device for such an application has not been established for routine use as yet. OPS imaging implemented into the CYTOSCAN A/R is a new, recently introduced technique which allows to obtain high contrast images of the microcirculation without the necessity for fluorescent dyes. The aim of the study was to validate OPS imaging as a tool to study microcirculation in skin after burn injury. OPS imaging was applied by no-touch technique and capillary blood flow was videotaped. Subsequent measurements of the microcirculation were performed at the identical site of the burn. Quantitative analysis of the microcirculation was performed off-line using CapImage. OPS imaging produces high quality images of the microcirculation in a burn wound. Data is given as the number of perfused capillaries per observation area (functional capillary density; FCD) [n/cm2]. OPS imaging allows for direct in vivo visualization and quantification of the microcirculation in burned skin. Our preliminary results of the use of OPS imaging in assessing the microcirculation in burns appear promising, and we hope that this novel technique will allow to improve the knowledge of the dynamics of the microcirculation in the pathophysiology of thermal injury.

Blood Flow Velocity↗
PubMed2002

[Intravital microscopic analysis of perfusion, leukocyte-endothelial cell interaction and neovascularization after burns: an in vivo study of SKH-1/hr hairless mice]].

Breakdown of skin microcirculation is supposed to play a key role in pathophysiology of burn injury. The aim of the study was to develop a burn model, which allows repetitive quantitative in vivo analysis of microcirculation after burn injury with special focus on leukocyte endothelium interaction over a longer period of time. Male hairless mice (SKH-1/hr) were used. Deep partial thickness burns were inflicted in no-touch-technique to the ears. Intravital fluorescent microscopy in combination with FITC-dextran as a plasma-marker was used to assess standard microcirculatory parameters. Leukocytes were stained with rhodamine-6-G to study their interaction with the endothelium.

Animals↗