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C Hofmann

Publications and source records attributed to C Hofmann.

At least 37 records · Page 2Linked to original sources
PubMed2001

The role of the urokinase-type plasminogen activator (uPA) and its receptor (CD87) in lipodermatosclerosis.

BACKGROUND: Lipodermatosclerosis refers to a sclerosing panniculitis and dermopathy of the lower extremities sometimes seen in association with venous ulceration. Matrix metalloproteinases are implicated in the pathogenesis of venous leg ulcers and the in vitro activation of recombinant MMP-2 is controlled by the plasminogen activation system. To better understand the role of plasminogen activation in the pathogenesis of venous leg ulcers we investigated fibrinolytic factors and their inhibitors in tissue samples of lipodermatolsclerosis. METHODS: The expression and the functional state of the urokinase-type plasminogen activator (uPA), the tissue-type plasminogen activator (tPA), the urokinase receptor (CD87), the plasminogen activator inhibitors-1 and -2 (PAI-1 and PAI-2) were assayed using reverse transcription polymerase chain reaction, Western blot, fibrin zymography and immunohistochemistry analyses in tissue samples of lipodermatosclerosis. RESULTS: Our results provide direct evidence of elevated expression of uPA (p<0.01) and CD87 (p<0.01) mRNA and protein level in lipodermatosclerosis in comparison with healthy skin. By immunohistochemistry, elevated expression of uPA and CD87 could be detected. Fibrin zymography showed significantly elevated endogenous uPA activity (p<0.01) in liposclerotic lesions compared to healthy controls. CONCLUSION: Our findings indicate that elevated plasminogen activation in lipodermatosclerotic tissue may play a crucial role in the pathogenesis of venous leg ulceration.

Blotting, Western↗
PubMed2001

Incorporation of decay-accelerating factor into the baculovirus envelope generates complement-resistant gene transfer vectors.

Baculovirus vectors are an efficient means to deliver genes into hepatocytes in vitro. In experiments that exclude components of the complement system, gene transfer is facilitated. Therefore, the complement system has been defined to represent a potent primary barrier to direct application of baculoviruses in vivo. Here we have genetically manipulated baculoviruses so that the complement-regulatory protein human decay- accelerating factor (DAF) is incorporated into the viral envelope. We found that this modification protected baculovirus vectors against complement-mediated inactivation. Complement-resistant baculovirus vectors were additionally analyzed by immunoblotting and electron microscopy, showing the extent of envelope-incorporated DAF and shape of complement-resistant baculoviruses after exposure to complement. This modified baculovirus vector allowed for an enhanced gene transfer into complement-sufficient neonatal rats in vivo, and thus represents a step in the development of improved alternative viral vectors for gene therapy.

Animals↗
PubMed2001

[Living organ donation vs. cadaveric donation - study of liver transplanted children and their families].

There is only scarce information on the quality of life of child recipients of liver transplants and their families. Particularly children with a living related graft and their families never have been compared to children who received a cadaveric graft and their families. We investigated the following issues in our study: How do parents and children from participating families rate their strain, their quality of life and their relationships within their family? Do families with a living - related donor differ from those with a cadaveric donor? What do living donors and their partners think about the donation retrospectively? The study was conducted with 106 participants from 50 families (42 mothers, 40 fathers, and 24 children older than 6 years). In 20 of these families, a living transplantation had been performed. Participants were interviewed and asked to fill out several questionnaires. School-aged children with a liver transplant show good social integration among their peers and in school. The child's disease, however, has a great impact on the family. Family members show a reduction in social contact, and an increase in marital crises, and problematic relations amongst siblings. Families in which a cadaveric graft was performed, are less satisfied with life, and show more symptoms of exhaustion. Every family studied possessed or acquired - a high degree of internal or external coping resources. Living - related donors tried hard to obtain an understanding of the medical context. The partner, rather than the donor himself, feels anxious before the donation. The limited time available for the decision to donate is not perceived by the donors to be critical. Ten percent of living donors feel "a little" that their health is affected. The decision to donate is supported "strongly" or "very strongly" by the partners in 80 % of the cases. A possible strain on the child through the expectation of gratitude by the donor is stated by 20 %. All of the donors agree that if they were to be asked today, they would donate again, only one of the partners raised objections. In summary, as a retrospective pilot study, this study primarily generates hypotheses rather than testing them and helps to develop research tools for the field. Results suggest that a psychological support be made available both prior to and following the operation, not only for the children but also for their families, with particular attention to the partners of the living donors and the siblings of the affected children.

Adolescent↗
PubMed2000

Metabolism and function of 3-D-phosphorylated phosphoinositides in C5a-stimulated eosinophils.

Eosinophils play a central role in the pathogenesis of parasitic infections, atopic diseases, and bullous dermatoses. To understand the regulative function of phosphatidylinositol 3-kinases in cell responses of eosinophils, phospholipid metabolism and production of reactive oxygen metabolites were followed after stimulation with C5a. Measurements of phosphatidylinositol lipids and analysis of deacylated products of separated lipid extracts showed fast and transient formation of phosphatidylinositol 3,4,5-trisphosphate (PIP(3)). Cell studies in the presence of the tyrosine kinase blocker genistein indicated that C5a-stimulated PIP(3) formation occurred independently of tyrosine kinase activity. To analyze the function of PI4,5P(2)-3-kinase in eosinophils, the influence of wortmannin and LY294002 on production of reactive oxygen metabolites was studied. Both compounds inhibited with similar concentration dependency C5a-induced formation of PIP(3) and production of reactive oxygen metabolites. In summary, these data showed for the first time the involvement of PI4,5P(2)-3-kinase in the production of reactive oxygen metabolites in eosinophils.

Androstadienes↗
PubMed2000

Adenosine triphosphate-induced oxygen radical production and CD11b up-regulation: Ca(++) mobilization and actin reorganization in human eosinophils.

Eosinophils are major effector cells in cellular inflammatory conditions such as parasitic infections, atopic diseases, bullous dermatoses, and vasculitis. Biological activities of adenosine triphosphate (ATP) were characterized in human eosinophils and compared with those of other eosinophil activators such as complement fragment product C5a, platelet-activating factor (PAF), and eotaxin. ATP initiated production of reactive oxygen metabolites, as demonstrated by lucigenin-dependent chemiluminescence. Furthermore, ATP caused up-regulation of the integrin CD11b. In addition, fluorescence microscope measurements labeled with fura-2 (1-[2-(5-carboxy-oxazol-2-yl)-6-aminobenzofuran-5-oxy]-2-(2' -amino-5' -methyl-phenoxy)-ethane-N, N, N, N'-tetraacetic acid, pentaacetoxymethyl ester) eosinophils in the presence or absence of ethyleneglycotetraacetic acid (EGTA) indicated that there was Ca(++) mobilization from intracellular stores by ATP. Flow cytometric studies showed transient actin polymerization upon stimulation with ATP and its stable analogues adenosine 5'-0-(3-thiotriphosphate) and 2-methylthioadenosine triphosphate tetrasodium (met-ATP). The reactions induced by ATP were comparable to those obtained by C5a, PAF, and eotaxin. Production of reactive oxygen metabolites and actin polymerization after stimulation with ATP was inhibited by pertussis toxin, which indicated involvement of receptor-coupled guanine nucleotide-binding proteins (G(i) proteins). In addition, experiments with oxidized ATP also suggest involvement of P2X receptors in this activation process. The results show that ATP is a strong activator of eosinophils and has biological activity comparable to those of the eosinophil chemotaxins C5a, PAF, and eotaxin. The findings strongly suggest a role of ATP in the pathogenesis of eosinophilic inflammation as an activator of proinflammatory effector functions.

Actin Cytoskeleton↗
PubMed2000

A mouse model for valproate teratogenicity: parental effects, homeotic transformations, and altered HOX expression.

Valproate (VPA) is one of several effective anti-epileptic and mood-stabilizing drugs, many of which are also potent teratogens in humans and several other mammalian species. Variable teratogenicity among inbred strains of laboratory mice suggests that genetic factors influence susceptibility. While studying the genetic basis for VPA teratogenicity in mice, we discovered that parental factors influence fetal susceptibility to induced malformations. Detailed examination of these malformations revealed that many were homeotic transformations. To test whether VPA, like retinoic acid (RA), alters HOX expression, pluripotent human embryonal carcinoma cells were treated with VPA or RA and Hox expression assessed. Altered expression of specific Hox genes may thus account for the homeotic transformations and other malformations found in VPA-treated fetuses.

Abnormalities, Drug-Induced↗
PubMed2000

[Effect of various bone disinfection and sterilization methods on osteoblast function. A comparative in vitro study].

All sterilization and disinfection procedures for bone grafts are different in regard to influence of bone graft features, which may influence the function of different cell types. We used an in-vitro approach to assess the influence of bone matrix, which was sterilized or disinfected, on osteoblastic activities in-vitro by simulating a cell-transplant-interface. Primary bovine osteoblast cell cultures were established from periosteum. Bone graft specimens made of bovine cortical bone (O 15 mm, 300 microns thickness) were treated in 5 different ways: autoclaved, ethylene-oxide-sterilized, demineralized and low-temperature-plasma-sterilized (DEM-LTP), chemically sterilized (modified Tutoplast method), and 80 degrees C-temperature disinfected. The following cell function parameters were assayed: plating efficiency proliferation by measuring the DNA-content, and MTT-activity, soluble protein and extracellular matrix synthesis, alkaline phosphatase, and osteocalcin expression. All disinfected bone grafts were biocompatible with primary periosteal osteoblasts. Measured cell activities upon bone specimens showed better results than cells of the plastic surface control. The DEM-LTP-bone showed better results in comparison to other groups, and stimulated the proliferation and differentiation.

Animals↗
PubMed2000

HNA-1a, HNA-1b, and HNA-1c (NA1, NA2, SH) frequencies in African and American Blacks and in Chinese.

The granulocyte antigens HNA-1a, -1b, and -1c (formerly named NA1, NA2 and SH) which reside on the neutrophil FcgammaReceptor IIIb (FcgammaRIIIb) play a major role in immune neutropenias and pulmonary transfusion reactions. In an attempt to shed some light on the origin and history of these antigens we typed the DNA of Blacks from South Africa (n=99), and Ghana (n=27), of 56 African Americans, and of 138 Chinese from Taiwan for HNA-1a,-1b, and -1c antigens using polymerase chain reaction with sequence-specific primers (PCR-SSP). In African and American Blacks, the HNA-1b antigen was more frequent than HNA-1a (77 vs. 67% and 77 vs. 59%, respectively). In contrast, in Chinese HNA-1a was more frequent than HNA-1b (91 vs. 54%). We observed 3 individuals with FcgammaRIIIB deficiency among the 126 tested African Blacks indicating a higher frequency of FcgammaRIIIB deficiency in Blacks than the reported 0.1% in Europeans. In addition, the frequency of HNA-1c in African and American Blacks (38 and 23%, respectively) was higher than the reported 5% in Europeans. Among the 57 HNA-1c (+) Blacks, all were HNA-1b (+) but only 26 were HNA-1a (+) supporting the idea that the HNA-1c antigen is the result of an additional point mutation in the allele coding for HNA-1b. Recently, HNA-1a, -1b, and -1c (+) Europeans have been reported to have three distinct FcgammaRIIIB genes. Among 26 Blacks who had been typed HNA-1a,b,c (+) by PCR-SSP we identified only 7 having three FcgammaRIIIB genes by DNA sequencing. When we sequenced the DNA of 6 HNA-1a,b,c (+) Europeans we found 4 of the individuals had three FcyRIIIB genes. Therefore, we assume that in Africa the point mutation occurred first in the HNA-1b allele resulting in the HNA-1c allele and the FcgammaRIIIB gene duplication took place later.

Asian People↗
PubMed2000

Ovine adenovirus vectors mediate efficient gene transfer to skeletal muscle.

Ovine adenovirus (OAV) vectors represent a promising tool for human gene therapy since these vectors overcome the problem of pre-existing immunity against human adenovirus vectors. In this report we investigated the in vivo characteristics of this novel vector system with respect to its potential for gene transfer into skeletal muscle. We found that moderate doses of an OAV-derived vector expressing the human alpha1-antitrypsin gene (OAVhaat) infected skeletal muscle in mice very efficiently resulting in high serum hAAT levels. The infection was restricted to skeletal muscle, but gene expression was transient and vector DNA was rapidly cleared. Vector clearance was also observed with a vector that lacked the transgene. The loss of vector DNA was accompanied by a cellular immune response in the infected muscle but was not connected with detectable expression of early or late genes of the viral backbone as analyzed by RT-PCR. A very low dose of OAVhaat (3x 10(7) infectious particles) was sufficient to produce reasonable amounts (>100 ng/ml) of serum hAAT, and this was accompanied by a weak immune response to the vector. Under these conditions, a second intramuscular injection of the same recombinant OAV vector was successful. Our study expands the known tissue tropism of OAV-derived vectors in vivo and points to the possible utility of the vector for muscle gene transfer and vaccination.

Animals↗
PubMed2000

Improved sedation in diagnostic and therapeutic ERCP: propofol is an alternative to midazolam.

BACKGROUND AND STUDY AIMS: Adequate sedation of the patient is required for diagnostic and therapeutic endoscopic retrograde cholangiopancreatography (ERCP). The anesthetic propofol, with its shorter half-life, affording better control, offers an alternative to the benzodiazepine midazolam. The aim of this randomized, controlled, unblinded study was to compare prospectively the quality of sedation under propofol and midazolam in patients undergoing ERCP. PATIENTS AND METHODS: A total of 80 patients were randomized to sedation with propofol alone (n = 40) or midazolam alone (n = 40). Blood pressure, pulse, and oxygen saturation were measured. Midazolam was given by the endoscopist and titrated to the patients' response during ERCP, to a maximum dose of 15 mg per patient. In the propofol group an anesthetist was present to administer the propofol and to observe the patient. Standardized testing procedures (Steward score, Trieger test) were used to determine the length of postendoscopy recovery time. Efficacy of sedation was assessed by investigators and patients, using scoring systems. RESULTS: Complete ERCP and adequate sedation was possible in 80% of patients (32 out of 40) with midazolam, and in 97.5% of patients (39 out of 40) with propofol (P<0.01). The average propofol induction dose was 1.24 mg/kg body weight, with maintenance requiring a mean dose of 9 mg/kg body weight per hour, or the equivalent of 354 mg in total. The average dose of midazolam administered was 0.12 mg/kg body weight; the total dose averaged 8 mg. Recovery time in the propofol patients was significantly shorter (P<0.01). The investigators (P<0.01) and the patients (P<0.05) both judged the quality of sedation to be better in the propofol group. There were no differences in blood pressure, pulse, or oxygen saturation between the two groups. One patient in the propofol group (79 years old) suffered a protracted apneic phase accompanied by hypotension that was managed by manual ventilation and drug therapy, and led to no complications. CONCLUSIONS: Propofol proves to be an excellent sedative for ERCP and shows a shorter recovery time than midazolam. Because of the narrow therapeutic window, we recommend close patient monitoring.

Anesthesia Recovery Period↗
PubMed2000

Upper esophageal sphincter function during gastroesophageal reflux events revisited.

Upper esophageal sphincter (UES) function during gastroesophageal reflux events is not completely elucidated because previous studies addressing this issue yielded conflicting results. We reexamined the UES pressure response to intraluminal esophageal pressure and pH changes induced by reflux events. We studied 14 healthy, asymptomatic volunteers (age 49 +/- 6 yr) and 7 gastroesophageal reflux disease patients (age 48 +/- 5 yr). UES pressure, intraesophageal pressure, and pH were monitored at the distal, middle, and proximal esophagus concurrently in the supine position 1 h before and 2 h after a 1,000-calorie meal. A total of 321 reflux events were identified by the development of abrupt reflux-induced intraesophageal pressure increase (IPI); 285 events occurred in patients and 36 in control subjects. In control subjects 33 of 36 and in patients 252 of 285 IPI events were associated with a pH drop. Among patients and control subjects, 99% and 100%, respectively, of all IPI events irrespective of pH drop were associated with abrupt increase in UES pressure (34 +/- 2 and 27 +/- 6 mmHg, respectively). The average percentage of maximum UES pressure increase over prereflux values ranged between 66% and 96% (control subjects) and 34% and 122% (patients). IPIs induced by both acidic and nonacidic reflux events evoke strong UES contractile responses.

Acids↗
PubMed2000

A model for anteroposterior patterning of the vertebrate limb based on sequential long- and short-range Shh signalling and Bmp signalling.

It has been proposed that digit identity in chick limb bud is specified in a dose-dependent fashion by a long-range morphogen, produced by the polarising region. One candidate is Sonic hedgehog (Shh) protein, but it is not clear whether Shh acts long or short range or via Bmps. Here we dissect the relationship between Shh and Bmp signalling. We show that Shh is necessary not only for initiating bmp2 expression but also for sustaining its expression during the period when additional digits are being specified. We also show that we can reproduce much of the effect of Shh during this period by applying only Bmp2. We further demonstrate that it is Bmps that are responsible for digit specification by transiently adding Noggin or Bmp antibodies to limbs treated with Shh. In such limbs, multiple additional digits still form but they all have the same identity. We also explored time dependency and range of Shh signalling by examining ptc expression. We show that high-level ptc expression is induced rapidly when either Shh beads or polarising regions are grafted to a host limb. Furthermore, we find that high-level ptc expression is first widespread but later more restricted. All these data lead us to propose a new model for digit patterning. We suggest that Shh initially acts long range to prime the region of the limb competent to form digits and thus control digit number. Then later, Shh acts short range to induce expression of Bmps, whose morphogenetic action specifies digit identity.

Animals↗
PubMed2000

Autologous platelet-derived wound healing factor promotes angiogenesis via alphavbeta3-integrin expression in chronic wounds.

Healing of venous leg ulcers depends on the adhesive interaction and formation of new vascular cells. Angiogenesis on the surface of angiogenic blood vessels requires the vascular integrin alphavbeta3 also known as the vitronectin receptor. Autologous platelet-derived wound healing factor (autologous PDWHF) has been described to regulate the wound healing process by forming granulation tissue in the early healing phase. Here we analysed the influence of autologous PDWHF on the expression of the alphavbeta3 integrin in tissue specimen of venous leg ulcers in comparison with placebo treated controls by using reverse transcriptase-polymerase chain reaction and immunohistochemistry. Our investigations provide evidence that mRNA and protein expression of alphavbeta3 were significantly increased in healing venous leg ulcers after 96 h treatment (p<0.05), whereas the total amount of alphavbeta3 mRNA and protein was not altered in placebo treated patients. In healing leg ulcers the alphavbeta3 integrin was predominantly localized around capillary vessels preferentially at sites of newly formed granulation tissue. Placebo controlled patients displayed no altered expression of the alphavbeta3 integrin in biopsy specimen. These findings suggest that topical autologous platelet-derived wound healing factor influences the process of angiogenesis/revascularization via alphavbeta3 integrin-expression hereby promoting granulation tissue formation in healing leg ulcers.

Aged↗
PubMed1999

The use of allele-specific recombinant Fc gamma receptor IIIb antigens for the detection of granulocyte antibodies.

The Fcgamma receptor IIIb (FcgammaRIIIb) for the Fc domain of IgG is expressed exclusively on neutrophils. The FcgammaRIIIb bears allotypic polymorphisms referred to as NA1, NA2, and SH, which are known for their frequent involvement in alloimmune and autoimmune neutropenias as well as in transfusion reactions. The bactericidal capacity of isolated neutrophils is easily activatable, and activation results in self-desintegration, thus preventing storage of neutrophils. As a result, only freshly isolated granulocytes can be used for antibody screening, often making it impossible to use typed panel cells. To provide a readily available source of typed panel cells, we therefore established stable mammalian cells expressing recombinant NA1, NA2, and SH antigens. We isolated mRNA from typed neutrophils and then transcribed it in cDNA. The cDNA that codes for the different forms of the FcgammaRIIIb was amplified by polymerase chain reaction and was subsequently subcloned into the mammalian expression vector pcDNA3. Chinese hamster ovary (CHO) cells were transfected with allele-specific constructs, and stable cell lines expressing FcgammaRIIIb were selected by flow cytometry. Because human sera show high background fluorescence with transfectants in flow cytometry, the monoclonal antibody-specific isolation of granulocyte antigens (MAIGA) assay was performed. By MAIGA assay, we tested 14 well-characterized human alloantibodies directed against the antigens NA1, NA2, and SH; 5 FcgammaRIIIb-specific isoantibodies; and 12 FcgammaRIIIb-reactive autoantibodies. Except one NA1- and one SH-specific alloantibody, all other antibodies could be identified by the use of CHO transfectants. In contrast to neutrophils, fixed CHO cells can be stored at 4 degrees C for at least 4 weeks or stored frozen for a longer period. This longer shelf life of the transfected CHO cells compared with isolated neutrophils will simplify the detection of the clinically most important FcgammaRIIIb-reactive alloantibodies and autoantibodies.

Alleles↗
PubMed1999

Angioscotoma detection with fundus-oriented perimetry. A study with dark and bright stimuli of different sizes.

Fundus-oriented perimetry (FOP) was used to evaluate the effectiveness of different-sized bright and dark stimuli in detecting and quantitatively measuring angioscotoma. The foveolas and optic disks of digitized fundus images were aligned with their psychophysical counterparts to construct individual grids of perimetric stimuli. Each grid included a linear set of test point locations crossing a retinal vessel. Angioscotomas immediately became visible in nine of 13 healthy normal volunteers tested with FOP. Additional mathematical processing of local loss of differential light sensitivity (dls) disclosed an angioscotoma for at least one stimulus condition in all persons tested. The angioscomas were usually deeper for small (12) targets than for large (32') ones. On the other hand, the overall noise at dls thresholds was generally higher for small than for large stimuli regardless of whether the stimuli were bright or dark. No noteworthy differences were found in detection rates or signal-to-noise ratios under different stimulus conditions (dark/bright/small/large). FOP permits the individual arrangement of stimuli for specific morphological conditions and is thus capable of detecting even minute visual field defects such as angioscotomas.

Adult↗
PubMed1999

Serum G-CSF levels are not increased in patients with antibody-induced neutropenia unless they are suffering from infectious diseases.

By the use of a G-CSF-specific ELISA we determined the serum granulocyte-colony stimulating factor (G-CSF) levels in 63 patients with antibody-induced neutropenia including neonatal immune neutropenia, autoimmune neutropenia, and drug-induced immune neutropenia. In the sera of 20 patients, elevated G-CSF levels of 60-1006 pg/ml (normal <39 pg/ml) were observed. These patients suffered from infectious diseases at the time of blood collection. G-CSF levels normalized after successful antibiotic treatment, indicating that increased G-CSF production in patients with immune neutropenia may be primarily the result of infection and not of neutropenia.

Adult↗
PubMed1999

Ovine adenovirus vectors overcome preexisting humoral immunity against human adenoviruses in vivo.

Recombinant human adenoviruses (hAd) have become widely used as tools to achieve efficient gene transfer. However, successful application of hAd-derived vectors in clinical trials is limited due to immunological and potential safety problems inherent in their human origin. In this study, we describe a recombinant ovine adenovirus (OAV) as an alternative vector for gene transfer in vivo. In contrast to an hAd vector, the OAV vector was not neutralized by human sera. An OAV vector which contained the cDNA of the human alpha1-antitrypsin (hAAT) gene linked to the Rous sarcoma virus promoter was generated and administered systemically to mice. The level and duration of hAAT gene expression was similar to that achieved with an hAd counterpart in both immunocompetent and immunodeficient mice. However, the tissue distribution of the OAV vector differed from that observed for hAd vectors in that the liver was not the dominant target. Significantly, we demonstrated efficient gene transfer with the OAV vector into mice immunized with hAd vectors and vice versa. We also confirm that the immune response to a transgene product can prevent its functional expression following sequential application of a vector. Our results suggest a possible solution to endemic humoral immunity against currently used hAd vectors and should therefore have an impact on the design of improved gene therapy protocols utilizing adenovirus vectors.

Adenoviruses, Human↗