Biomedical subjects

J Knop

Publications and source records attributed to J Knop.

At least 19 recordsLinked to original sources

PubMed2006

[Mechanisms of specific immunotherapy].

Specific immunotherapy (SIT) is a well-established and clinically effective treatment for allergic rhinitis and bronchial asthma. The immunological mechanisms of the subcutaneously applied immunotherapy have been partially elucidated over the past several years but are not completely understood. This report summarizes the immunological and immunoregulatory changes during SIT of wasp venom allergic patients. The induction of IL-10-producing regulatory T cells is described.

Dendritic Cells↗

PubMed2006

Inhibition of human allergic T-helper type 2 immune responses by induced regulatory T cells requires the combination of interleukin-10-treated dendritic cells and transforming growth factor-beta for their induction.

BACKGROUND: In grass pollen-allergic individuals, T cell anergy can be induced by IL-10-treated dendritic cells (IL-10-DC) resulting in the suppression of T helper type 1 (Th1) as well as Th2 cells. This study was performed to analyse whether such IL-10-DC-treated T cells are able to act as regulatory T cells (Treg) suppressing the function of other T cells in the periphery. As transforming growth factor (TGF)-beta is also a potential inducer of Treg, we additionally analysed the inhibitory capacity of TGF-beta-treated T cells in this system. MATERIALS AND METHODS: Freshly isolated CD4+ or CD4+ CD25- T cells from grass pollen-allergic donors were stimulated with autologous mature monocyte-derived allergen-pulsed DC in the presence or absence of T cells previously cultured with IL-10-DC- and/or TGF-beta. RESULTS: Anergic T cells induced by allergen-pulsed IL-10-treated DC or allergen-pulsed DC and TGF-beta enhanced IL-10 production and strongly inhibited IFN-gamma production of freshly prepared peripheral CD4+ or CD4+ CD25- T cells while proliferation and Th2 cytokine production were only slightly reduced. The combination of allergen-pulsed IL-10-treated DC and TGF-beta had an additional effect leading to a significant suppression also of Th2 cytokine production and proliferation. Suppression was not antigen-specific and was mainly mediated by cell-to-cell contact and by the molecule-programmed death-1 and only partially by CTLA-4, TGF-beta and IL-10. CONCLUSION: These data demonstrate that regulatory T cells that also suppress Th2 cytokine production are induced by two signals: TGF-beta and IL-10-DC. This is of importance for the regulation of allergic immune responses and might be exploited for future therapeutic strategies for allergic diseases.

Allergens↗

PubMed2004

Prediction of mortality at age 40 in Danish males at high and low risk for alcoholism.

OBJECTIVE: This prospective high-risk study examined the influence of father's alcoholism and other archival-generated measures on premature death. METHOD: Sons of alcoholic fathers (n = 223) and sons of non-alcoholic fathers (n = 106) have been studied from birth to age 40. Archival predictors of premature death included father's alcoholism, childhood developmental data, and diagnostic information obtained from the Psychiatric Register and alcoholism clinics. RESULTS: By age 40, 21 of the 329 subjects had died (6.4%), a rate that is more than two times greater than expected. Sons of alcoholic fathers were not more likely to die by age 40. Premature death was associated with physical immaturity at 1-year of age and psychiatric/alcoholism treatment. No significant interactions were found between risk and archival measures. CONCLUSION: Genetic vulnerability did not independently predict death at age 40. Death was associated with developmental immaturities and treatment for a psychiatric and/or substance abuse problem.

Adult↗

PubMed2003

[Septic thrombosis of the cavernous sinus due to folliculitis].

Sinus thrombosis is an acute life-threatening disease. While cavernous sinus thrombosis secondary to facial infections is described in the literature, it is uncommon. The key clinical characteristics are a facial infection, headache, chemosis and edema of the eyelid. The main differential diagnostic consideration is meningoencephalitis. Early diagnosis by angiography, magnetic resonance imaging and examination of CSF is important as treatment should be initiated as soon as possible in order to decrease morbidity and mortality. The mainstays of therapy are heparinization and appropriate intravenous antibiotic therapy.

Adult↗

PubMed2003

Infrequent early recanalization of greater saphenous vein after endovenous laser treatment.

OBJECTIVE: The frequency of recanalization of the greater saphenous vein (GSV) after endovenous laser treatment (ELT) is unclear. This study was undertaken to establish the incidence of early recanalization after ELT and to study the histopathologic features of reperfused and excised GSV. METHODS: One hundred nine GSV in 85 consecutive patients with clinical stage C(2-6) E(P,S) A(S,P,D) P(R) disease were treated with ELT. Twelve months of follow-up with duplex scanning at regular intervals was possible in 104 treated veins (95.4%) in 82 patients (96.5%). Recanalized vessels were removed surgically and examined at histopathology. RESULTS: ELT-induced occlusion proved permanent at duplex scanning over 12 months of follow-up in 94 of 104 GSV (90.4%) in 73 patients. In 4 patients, 5 GSV (4.8%) were recanalized completely after 1 week, after 3 months (n = 3), or after 12 months. Another 5 GSV (4.8%) in 5 patients exhibited incomplete proximal recanalization over the 12 months of follow-up. Finally, 9 recanalized vessels (8.6%) required further treatment with high ligation and stripping. Histopathologic analysis of recanalized GSV revealed a multiluminal pattern, as commonly noted in reperfusion after spontaneous thromboplebotic occlusion of the GSV. During follow-up, secondary incompetency of untreated lateral accessory saphenous veins was observed in two legs (1.9%). CONCLUSION: Early recanalization requiring retreatment is observed in less than 10% of GSV after ELT. The histopathologic pattern mimics recanalization after thrombophlebotic occlusion.

Adolescent↗

PubMed2003

Priming of T cells with Ad-transduced DC followed by expansion with peptide-pulsed DC significantly enhances the induction of tumor-specific CD8+ T cells: implications for an efficient vaccination strategy.

In recent years, vaccination strategies using antigen-presenting cells (APC) have been under investigation. Antigen delivery using genetic immunization through ex vivo transduction of dendritic cells (DC) is supposed to enhance the induction of antitumor responses in humans by activating a broad range of peptide-specific CD8+ T cells. In this study, we compared the potential of adenoviral (Ad)-transduced versus peptide-pulsed DC to induce melanoma-antigen (Ag)-specific T-cell responses in vitro. Whereas gp100-peptide-pulsed DC induced long-lasting specific CD8+ T-cell responses against single peptides, Ad-transduced DC induced broad and strong, specific immunity against various peptides of the gp100-Ag. Surprisingly, several restimulations led to decreasing gp100-specific and in parallel to increasing anti-adenoviral T-cell responses. Nevertheless, those anti-adenoviral T-cell responses provided an "adjuvant" effect by inducing an early release of high amounts of IL-2/IFN-gamma, therewith enhancing CTL induction in the initiation phase. Based on these data, we suggest a prime/boost vaccination strategy in melanoma patients--combining the use of Ad-DC and peptide-pulsed DC--to obtain efficient and long-term antitumor T-cell responses.

Adenoviridae↗

PubMed2003

Transcriptional targeting of dendritic cells for gene therapy using the promoter of the cytoskeletal protein fascin.

Strong cell-type-specific promoters are basic tools in gene therapy allowing for novel applications and focused strategies by transcriptionally targeting gene expression to selected cells. In immunotherapy, dendritic cells (DC) are of central importance, since they represent the principal inducers of immune responses. Here we describe isolation and use of the promoter of the murine actin-bundling protein fascin to target transcriptionally gene expression to cutaneous DC. Using the reporter gene enhanced green fluorescent protein (EGFP), we demonstrate that the fascin promoter mediates a strong antigen expression that is restricted to mature DC. DNA vaccination with antigen-encoding expression vectors under control of the fascin promoter using a gene gun resulted, consistently, in limited antigen expression by few directly transfected DC. Nevertheless, nearly as many antigen-specific CD8+ T cells directed against the encoded antigens EGFP and beta-galactosidase, respectively, were induced as with expression constructs under control of the ubiquitously expressed CMV promoter. This result impressively underlines the pivotal role of directly transfected DC in DNA vaccination. Immunization using the fascin promoter induced markedly lower levels of antigen-specific antibodies following single or repeated immunization. Thus, our DC-targeted DNA vaccination approach induces qualitatively distinct, predominantly cellular immune responses and provides new opportunities for immunotherapy.

Animals↗

PubMed2003

Pattern analysis of human cutaneous mast cell populations by total body surface mapping.

BACKGROUND: Mast cells (MCs), critical effector cells in allergic inflammation and innate immunity to bacteria, are located in large numbers in tissues that interface the external environment, including the skin. However, little is known about the distribution and numbers of human skin MCs. OBJECTIVES: To assess the influence of age, sex and skin region on size and spatial distribution of MC populations in normal human skin. METHODS: Biopsies of healthy skin were obtained from 150 male and female individuals (age range 10-86 years). MCs were quantified and mapped planimetrically by histomorphometry in 15 anatomical sites (abdomen, thorax, lower and upper back, lower and upper arm, lower and upper leg, foot, hand, chin, nose, cheek, forehead, back of head). RESULTS: No differences in skin MC numbers or distribution were found when comparing skin obtained from male or female and from young or old individuals. At all skin sites, regardless of age or sex, MC numbers were highest in the most superficial skin layers where up to 10-fold more MCs were found as compared with the subcutis, which consistently contained the lowest numbers of MCs. Interestingly, MC numbers were highest at peripheral skin sites (maximum: chin and nose) and lowest at central skin sites (minimum: abdomen). Thus, healthy human skin exhibits a proximal/distal and a central/peripheral MC gradient and 'skin MC numbers' may vary by a factor of more than 20, depending on the skin layer and skin site analysed. CONCLUSIONS: These findings support the recently identified role of MCs in the elicitation of protective immune responses against infectious microorganisms. One possible explanation for these unexpected findings is that skin site/layer-specific factors (e.g. the density of nerves or vessels, exposure to ultraviolet irradiation, frequency of minimal trauma) are involved in the regulation of skin MC numbers and distribution.

Adolescent↗

PubMed2002

[Significance of immunologic tolerance in dermatology].

The immunological tolerance processes enable the organism to distinguish between self and non-self and are, therefore, critical for an efficient immune system. Exogenous or endogenous factors that disturb tolerance mechanisms induce uncontrolled activation of the immune system and the development of autoimmune diseases. In the field of dermatology, the most relevant autoimmune diseases are connective tissue diseases and autoimmune bullous skin disorders. In contrast, increased activity of tolerance shuts down parts of the normal immune response and thus facilitates the development of neoplasia and microbial infections in the skin and other organs. Immunological mechanisms for the induction of tolerance have been studied with the help of experimental models of tolerance to contact allergens. T- and B-cells, as well as antigen presenting cells, in particular dendritic cells, are involved in the immunological mechanisms of tolerance. The modification of autologous immune cells of patients with malignant tumors, allergic and autoimmune diseases might have potential for the development of new therapies.

Animals↗

PubMed2002

[Experiences with therapy of stage IV metastatic malignant melanoma with "Legha Protocol" polychemoimmunotherapy].

BACKGROUND AND OBJECTIVE: Metastatic malignant melanoma (stage IV) is one of the most aggressive tumors. At the moment there is no safe therapy. Therefore the report of Legha et al., who achieved a rate of almost 10% of long-lasting complete remissions with a polychemoimmunotherapy using interleukin-2 and interferon-alpha in combination with cisplatin, vinblastine and dacarbazine, is a promising one. Because of these promising trends, we decided to treat our own patients with this therapy to examine the results, the side effects and the practicability on normal dermatological wards. PATIENTS/METHODS: From 1997 to 2000 we treated 28 patients with metastatic malignant melanoma with the polychemoimmunotherapy according to Legha's protocol. RESULTS: We achieved three complete (11.1%) and seven partial (25.9%) remissions (altogether 37%). Two of these patients are living relapse-free at the moment (7.4%). Three patients (11.1%) showed a stabilization of their disease, five patients (18.5%) had a mixed response and nine patients (33.3%) suffered progressive disease. CONCLUSIONS: The rate of complete and partial remissions was lower than those reported by Legha et al., however the rate of long-lasting complete remissions was almost identical. The follow-up time is still ongoing, so we have to limit our results to this period. We want to emphasize the practicability of this kind of therapy on normal dermatological wards in spite of the relatively high toxicity.

Adult↗

PubMed2002

Efficacy of recombinant adenovirus as vector for allergen gene therapy in a mouse model of type I allergy.

DNA-based immunization represents an attractive alternative approach to the current treatment of allergic diseases by specific immunotherapy with allergen extracts. In this study, we used a replication-deficient adenovirus vector (AdCMV), to examine the in vivo efficacy of preventive and therapeutic genetic immunization in a mouse model of type I allergy. Primary immunization with a recombinant adenovirus expressing the model antigen beta-galactosidase (AdCMV-(beta)gal) induced a Th1 immune response (predominance of IgG2a antibodies, high frequency of IFN-gamma producing T cells) and large numbers of cytotoxic T lymphocytes. Prophylactic vaccination with AdCMV-(beta)gal abolished the production of specific IgE following subsequent immunization with (beta)gal-protein, and skewed the Th2-biased immune response to a Th1-orientated response. In contrast, therapeutic administration of AdCMV-(beta)gal after priming with (beta)gal-protein neither significantly inhibited ongoing IgE production nor modulated a manifest Th2 immune response. Thus, allergen gene transfer via recombinant adenovirus represents an effective method to establish protection against the development of allergic disorders, but does not qualify as a therapeutic tool to interfere with ongoing high IgE production.

Adenoviridae↗

PubMed2002

Genetic immunization with a melanocytic self-antigen linked to foreign helper sequences breaks tolerance and induces autoimmunity and tumor immunity.

Mechanisms maintaining peripheral tolerance to self-antigens present a major obstacle for the development of antigen-specific melanoma vaccines, presumably because self-antigens are not able to stimulate a CD4 T-helper response. Using the melanosomal enzyme tyrosinase-related protein 2 (TRP2) expressed by melanocytes and most melanoma cells as a model self-antigen, we investigated whether linkage with a foreign immunogenic protein providing strong CD4 helper sequences would be able to circumvent tolerance and enhance the induction of antigen-specific tumor immunity. We found that genetic immunization of mice with cDNA encoding a fusion protein between enhanced green fluorescent protein (EGFP) from jellyfish and autologous murine TRP2 (EGFP.mTRP2) resulted in the stimulation of TRP2-reactive T cells in vivo. Importantly, immunization with EGFP.mTRP2 effectively protected mice against metastatic growth of B16 melanoma in the lungs and was associated with fur depigmentation as a sign of autoimmune-mediated destruction of melanocytes. Our results show that tumor vaccines consisting of self-antigens linked to immunogenic helper sequences can be successfully applied to the immunotherapy of melanoma and provide a scientific basis for the translation of this strategy in future clinical investigations.

Animals↗

PubMed2002

Thermal damage of the inner vein wall during endovenous laser treatment: key role of energy absorption by intravascular blood.

BACKGROUND: Despite the clinical efficacy of endovenous laser treatment (EVLT), its mode of action is incompletely understood. OBJECTIVE: To evaluate the role of intravascular blood for the effective transfer of thermal damage to the vein wall through absorption of laser energy. METHODS: Laser energy (15 J/pulse, 940 nm) was endovenously administered to explanted greater saphenous vein (GSV) segments filled with blood (n = 5) or normal saline (n = 5) in addition to GSVs under in vivo conditions immediately prior to stripping. Histopathology was performed on serial sections to examine specific patterns of damage. Furthermore, in vitro generation of steam bubbles by different diode lasers (810, 940, and 980 nm) was examined in saline, plasma, and hemolytic blood. RESULTS: In saline-filled veins, EVLT-induced vessel wall injury was confined to the site of direct laser impact. In contrast, blood-filled veins exhibited thermal damage in more remote areas including the vein wall opposite to the laser impact. Steam bubbles were generated in hemolytic blood by all three lasers, while no bubbles could be produced in normal saline or plasma. CONCLUSION: Intravascular blood plays a key role for homogeneously distributed thermal damage of the inner vein wall during EVLT.

Humans↗

PubMed2002

Subfascial endoscopic perforator surgery with tumescent local anesthesia.

BACKGROUND: Subfascial endoscopic perforator surgery (SEPS) has become an established procedure. OBJECTIVE: To evaluate SEPS with tumescent local anesthesia (TLA) using an single-port device originally designed for that purpose. METHODS: Patients selected for SEPS received subcutaneous infiltration of TLA into the medial aspect of the calf 20 minutes before surgery. Bipolar coagulation and dissection were used to treat incompetent perforators. RESULTS: Fifty-one patients with 67 legs of CEAP stages C3-C6 underwent SEPS with TLA. In 40 patients or 53 legs (79.1%) TLA alone allowed successful completion of the SEPS procedure. Five patients with 7 legs (10.4%) required additional intravenous analgesics during surgery. In 4 patients or 4 legs (6.0%) with marked dermatoliposclerosis, pain control with TLA was so inadequate that SEPS had to be stopped. CONCLUSION: SEPS with TLA is feasible in patients with CEAP stage C3-C6. However, patients with pronounced dermatoliposclerosis are likely to need more invasive analgesic measures.

Adult↗

PubMed2002

Gravimetrically controlled efficacy of subcorial curettage: a prospective study for treatment of axillary hyperhidrosis.

BACKGROUND: Botulinum toxin A (BTX-A) proved to be effective for the treatment of axillary hyperhidrosis by means of gravimetry. Quantitatively controlled studies for surgical treatment are lacking so far. OBJECTIVE: To prospectively test the efficacy of subcorial axillary curettage by gravimetric evaluation of pre- and postsurgical sweat rates. METHODS: Conservatively pretreated patients received subcorial curettage under tumescent local anesthesia using a sharp spoon. Sweat rates of each axilla were determined gravimetrically before and 4-8 weeks after surgery. Evaluation was performed with respect to baseline sweat rates greater than 50 mg/min (group A), greater than 25 and less than 50 mg/min (group B), and less than 25 mg/min (group C). Side effects and patients' ratings were also recorded. RESULTS: Of 42 treated patients, 38 could be evaluated completely. In 29 axillae of group A (high sweat rates), an average reduction from the baseline of 85.6 mg/min to 21.6 mg/min could be achieved (P <.0001). Corresponding values for 22 axillae of group B (medium sweat rates) were 36.8 mg/min and 16.5 mg/min (P <.0001). In 25 axillae with low sweat rates (group C), a significant reduction in sweat rates could not be achieved. The results remained almost stable during a median follow-up of 11 months (range 4-24 months). Only minor side effects were observed and patient satisfaction was high in groups A and B. CONCLUSION: Subcorial curettage is an effective treatment of axillary hyperhidrosis for patients with baseline sweat rates greater than 25 mg/min.

Adult↗

PubMed2002

Endovenous treatment of the greater saphenous vein with a 940-nm diode laser: thrombotic occlusion after endoluminal thermal damage by laser-generated steam bubbles.

PURPOSE: Despite a rapid spread of the technique, very little is known about the laser-tissue interaction in endovenous laser treatment (EVLT). We evaluated EVLT of the incompetent greater saphenous vein (GSV) for efficacy, treatment-related adverse effects, and putative mechanisms of action. METHODS: Twenty-six patients with 31 limbs of clinical stages C(2-6), E(P), A(S,P), P(R) with incompetent GSV proven by means of duplex scanning were selected for EVLT in an outpatient setting. A 600-microm fiber was entered into the GSV via an 18-gauge needle below the knee and proceeded to the saphenofemoral junction (SFJ). After infiltration of tumescent local anesthesia, multiple laser pulses of 15 J energy and a wavelength of 940 nm were administered along the vein in a standardized fashion. D-dimers were determined in peripheral blood samples 30 minutes after completion of EVLT in 16 patients and on postoperative day 1 in 20 patients. One GSV that was surgically removed after EVLT was examined by means of histopathology. Additionally, an experimental in vitro set-up was constructed as a means of investigating the mechanism of laser action within a blood-filled tube. RESULTS: A median of 80 laser pulses (range, 22-116 laser pulses) were applied along the treated veins. On days 1, 7, and 28, all limbs except one (97%) showed a thrombotically occluded GSV. In one patient, the vessel showed incomplete occlusion. The distance of the proximal end of the thrombus to the SFJ was a median 1.1 cm (range, 0.2-5.9 cm) in the remaining patients. Adverse effects in all 26 patients were ecchymoses and palpable induration along the thrombotically occluded GSV that lasted for 2 to 3 weeks. In two limbs (6%), thrombophlebitis of a varicose tributary required oral treatment with diclofenac. D-dimers in peripheral blood were tested with normal results in 14 of 16 patients 30 minutes after completion of the procedure and elevated results in 7 of 20 patients at day 1 after EVLT. However, an increase of D-dimers from day 0 to day 1 was observed in 15 of the 16 patients undergoing tests 30 minutes after EVLT and on day 1. The 940-nm laser was demonstrated by means of in vitro experiments and the histopathological examination of one explanted GSV to act by means of indirect heat damage of the inner vein wall. CONCLUSION: EVLT of the GSV with a 940-nm diode laser is effective in inducing thrombotic vessel occlusion and is associated with only minor adverse effects. Laser-induced indirect local heat injury of the inner vein wall by steam bubbles originating from boiling blood is proposed as the pathophysiological mechanism of action of EVLT.

Female↗

PubMed2001

Depletion of CD25(+) CD4(+) T cells and treatment with tyrosinase-related protein 2-transduced dendritic cells enhance the interferon alpha-induced, CD8(+) T-cell-dependent immune defense of B16 melanoma.

Transduction of B16 melanoma cells with IFN alpha (B16-IFN alpha) enhances CD8(+) T-cell-dependent tumor immunity in mice, resulting in delayed outgrowth in vivo. Here we provide evidence that CD4(+) T cells down-regulate the IFN alpha-induced tumor immune defense. Importantly, depletion of regulatory CD25(+) CD4(+) T cells prevented growth of B16-IFN alpha in most mice and promoted long-lasting protective tumor immunity. Rejection of B16-IFN alpha could also be achieved with therapeutic injections of dendritic cells genetically engineered to express the melanoma antigen tyrosinase-related protein 2. These results support the development of novel strategies for the immunotherapy of melanoma using IFN alpha in combination with elimination of regulatory T cells or antigen-specific immunization.

Animals↗

PubMed2001

[Psychological intervention during pregnancy. A multidisciplinary hospital network].

INTRODUCTION: Pregnancy and the puerperium are vulnerable periods in every woman's life. It is important to catch and treat signs of mental distress so as to prepare the woman for her approaching delivery, to optimize her role as a mother, and to prevent development of severe psychopathology. We describe a professional network (midwife, obstetrician, psychologist, and child psychiatrist) at a Danish county hospital, which offers the pregnant woman psychological therapy and/or psychiatric treatment when needed. MATERIAL AND METHODS: The study includes a retrospective analysis of 106 consecutive referrals from the department of obstetrics to the department of psychiatry in the period 1994-1999. The variables were frequency and reason for referral, the diagnostic profile according to ICD-10, the number of therapeutic sessions, and registration of pregnancy/birth complications (PBC). RESULTS AND DISCUSSION: Anxiety and crisis reactions owing to previous PBC, family problems, and concerns about the fetus were the predominant reasons for referral. A total of 87% met the ICD-10 criteria for adjustment disorder (F 43.2), whereas psychotic disorders were infrequent. In 52%, 1-4 sessions were sufficient to stabilise the condition. The frequency of PBC in the 106 women was significantly higher when compared to the background sample (n = about 15,000). The establishment of an effective network is recommended for pregnant women suffering from mental distress in order to prepare her for the approaching delivery, to optimise her forthcoming role as a mother, and to prevent development of severe psychopathology.

Denmark↗