Biomedical subjects

P Jecker

Publications and source records attributed to P Jecker.

At least 37 records · Page 2Linked to original sources

PubMed2001

Proliferating macrophages, dendritic cells, natural killer cells, T and B lymphocytes in the middle ear and Eustachian tube mucosa during experimental acute otitis media in the rat.

Although many studies focus on the increase of immunocompetent cells within the middle ear mucosa during acute otitis media it is poorly understood how this increase is mediated. The differentiation between two possible causes, i.e. immigration and local proliferation, would help to better understand the pathophysiology of this disease. Therefore, the number of proliferating macrophages, dendritic cells, natural killer cells and T and B lymphocytes was studied during acute otitis media in the rat middle ear mucosa (ME mucosa) and Eustachian tube mucosa (ET mucosa) by labelling proliferating leucocytes with the DNA precursor bromodeoxyuridine (BrdU). By removing the middle ear and Eustachian tube 24 h after BrdU injection, the contribution of immigrated newly formed cells was estimated. At this timepoint, many leucocytes in the ME and ET mucosa had incorporated BrdU (between 15 and 25% within the subsets). By analysing these tissues one hour after BrdU injection, the local proliferation rate was determined (between 2 and 9% within the subsets). Thus, the inflamed ME and ET mucosa are the destination of immunocompetent cells and, as our data show, the inflamed microenvironment supports local proliferation of immunocompetent cells.

Acute Disease↗

PubMed2001

[The Interesting Case No. 42. Differential diagnosis of epistaxis].

Epistaxis is a symptom and one of the most frequent medical emergencies. In most cases haemorrhages concern the anterior parts of the septum, in particular the Locus Kiesselbachi. Thus they are harmless and therapy is easy to handle. We report a case of a 55-year-old lady with relapsing epistaxis due to a pseudoaneurysm after surgery of a meningioma of the sphenoid bone. This type of epistaxis is rare and may culminate into a life-threatening event. The case demonstrates the importance of an exact differential diagnostic evaluation by use of modern imaging techniques for severe and life-threatening symptomatic nose-bleeding.

Aneurysm, False↗

PubMed2001

[Improved tumor site and contrast resolution in ultrasound diagnosis by using harmonic frequencies].

BACKGROUND: The aim of new techniques in head and neck sonography is to increase the sensitivity and the specificity of the examination. With tissue harmonic imaging (THI) and contrast harmonic imaging (CHI) new techniques are available which allow increased contrast and resolution in head and neck sonography as well as a better detection of small blood vessels. METHODS: We studied whether these techniques improve sonographic detection of head and neck lymph nodes and primary tumours of the upper aerodigestive tract. RESULTS: The results indicate that THI allows a better detection of cervical lymph nodes. Furthermore, intranodal structures and the borders of the lymph node can be better detected. Using CHI, typical patterns of vascularization can be seen, allowing a better interpretation of the node's tumour status. Primary tumours can be detected sufficiently well using conventional B-scan techniques although they are easier to detect with THI. Using CHI, many tumour vessels can be detected, but this does not increase the sensitivity of the sonographic examination. CONCLUSION: THI and CHI may increase the specificity of sonographic diagnostics of cervical lymph nodes but show no clinical benefit regarding the diagnostics of primary tumours of the upper aerodigestive tract.

Contrast Media↗

PubMed2001

[Ultrasound characteristics of lateral cervical space-occupying lesions].

UNLABELLED: Sonography of the head and neck mainly focuses on tumours of the lateral neck. Even though most of these masses are enlarged lymph nodes, other tumors have to be considered. AIM: To determine whether different pathological cervical masses display a characteristic sonographic morphology. METHOD: On the basis of 530 sonographical findings in the neck, typical ultrasound characteristics either in B-scan or in colour coded sonography were demonstrated. RESULTS: Apart from enlarged lymph nodes, it was possible to differentiate other occurrences such as branchial cysts, abscesses, laryngoceles, lipomas, neurinomas, glomus tumours, paragangliomas and also fibromas by their specific ultrasound appearance. CONCLUSION: Knowledge of characteristic ultrasound morphology allows the early detection of tumours and facilitates the distinction between benign and malignant lesions as well as malformations. Further diagnostic procedures and therapeutical strategies can therefore be planned more adequately.

Abscess↗

PubMed2001

[Dysphagia without clinically relevant pathological correlation: to exclude tumours of the floor of the mouth and the base of the tongue ultrasound diagnosis is mandatory].

In patients suffering from dysphagia, a tumour of the tongue and its base must be excluded. This is not always possible by means of endoscopy and palpation. In contrast it is possible to visualize deep-seated structures of this region by ultrasound. Unfortunately, this technique is rarely used, as shown in the cases demonstrated. We present five patients suffering from dysphagia for a long period of time (up to 30 years) where ultrasound was not performed and a tumour of the floor of the mouth and the base of the tongue was overlooked. Thus, adequate therapy was delayed, which proved to be especially relevant in three patients suffering from a malignoma. Three patients suffered from a malignant tumour of the base of the tongue. Up to two years passed between the beginning of dysphagia and the necessary surgical treatment. One of these patients even underwent psychological treatment for his symptoms. In two other patients a dermoid cyst and ectopic thyroid tissue were removed. In patients suffering from dysphagia with normal endoscopic findings and normal palpation of the neck ultrasound of the floor of the mouth and the base of the tongue is imperative. Tumours of this area can be detected early with high sensitivity and cost-effectiveness by ultrasound.

Adult↗

PubMed2001

Acute laryngotracheitis in the rat induced by Sendai virus: the influx of six different types of immunocompetent cells into the laryngeal mucosa differs strongly between the subglottic and the glottic compartment.

OBJECTIVES: Acute laryngotracheitis is a disease in which mainly the subglottic area is infected, whereas adjacent parts of the larynx, especially the narrow glottic fold, remain unaffected. The reason for the difference between these two directly adjacent regions is unknown. Therefore, in the present study the influx of dendritic cells, neutrophils, T and B lymphocytes, natural killer cells, and macrophages into the mucosa of different laryngeal compartments was investigated after Sendai virus infection in the rat. The aims were to study both the influx of immunocompetent cells and the adhesion of the pathogen and to correlate them to the different reactions of the laryngeal areas during pseudocroup. METHODS: Acute laryngotracheitis was induced by intranasal application of Sendai virus in brown Norway rats. This virus is exclusively pneumotropic in rodents and belongs to the parainfluenza virus type 1, the main pathogen of acute laryngotracheitis in children. The numbers of dendritic cells, neutrophils, T and B lymphocytes, natural killer cells, and macrophages were determined in the supraglottic, glottic, subglottic, and tracheal mucosa on days 2, 5, 7, and 14 after virus application. Furthermore, the nucleoprotein of the virus and major histocompatibility complex (MHC) Class II expression were detected immunohistologically on the laryngeal epithelium. RESULTS: All cell subsets entered the laryngeal mucosa during inflammation. The highest influx was detected among dendritic cells subglottically. This was accompanied by a strong virus adhesion and MHC Class II expression on the subglottic epithelium. In contrast, only a few immunocompetent cells entered the adjacent glottic mucosa, and on the glottic epithelium staining for virus nucleoprotein and MHC Class II expression was weak. CONCLUSIONS: The inflammatory response of the laryngeal mucosa shows great regional differences in this animal model during experimental viral infection. The response was characterized by a strong subglottic and a weak glottic reaction. A possible reason for this difference might be region-specific viral adhesion on the epithelium of the laryngeal areas, as well as differences in MHC Class II expression. Thus, these data agree with the clinical observation during acute laryngotracheitis and may explain why the subglottic part of the larynx is affected preferentially during pseudocroup. The molecular mechanisms mediating the different reactions await clarification.

Acute Disease↗

PubMed2000

Color-coded duplex sonography of the cervical lymph nodes: improved differential diagnostic assessment after administration of the signal enhancer SH U 508A (Levovist).

The vascularity of cervical lymph nodes can be documented by means of color-coded duplex sonography and malignant and benign lymph nodes distinguished on the basis of typical patterns of vascularity. However, not all intranodal vessels can be visualized by color-coded duplex sonography, and minute vessels are detectable only after the administration of a signal enhancer. This also makes it possible to assess the morphology of cervical lymph nodes that are inaccessible on plain sonography. In the present study we examined acute and chronic inflammatory and metastatic lymph nodes as well as malignant lymphomas to determine the extent to which a specific pattern of vascularity can be detected with color-coded duplex sonography after the injection of Levovist as a signal enhancer. In addition, digital image processing was used to quantify the vascularity detected in relation to the cross-sectional area of the lymph nodes as seen at sonography and to determine whether there are any differences in lymph node types as regards an increase in the detection of vascularity. After injection of the marker a typical pattern of vascularity could be assigned to all lymph nodes examined and differences shown in quantifying vascularity: This increase was greatest in the acutely inflamed lymph nodes (36.0 +/- 5.0%) and smallest in lymph nodes with chronic inflammation (2.3 +/- 1.3%). These findings show that cervical lymph nodes of varying origin differ by virtue of their pattern of vascularity, with increased vascularity detectable after administration of a signal enhancer.

Carcinoma, Squamous Cell↗

PubMed2000

Differences in lymphocyte subsets in the wall of high endothelial venules and the lymphatics of human palatine tonsils.

Lymphocyte trafficking plays a critical role in disseminating specifically primed lymphocytes all over the body. Most concepts on the interaction of adhesion molecules on lymphocyte subsets and specialized endothelia such as those in high endothelial venules (HEV) are based on animal experiments as kinetic studies cannot be performed in humans. We therefore characterized lymphocyte subsets in the wall of HEV and in the lumen of lymphatics of 18 human palatine tonsils by immunohistology. All subsets studied were found in the wall of HEV (% of lymphocytes): 32% CD20+, 50% CD3+, 14% CD4+, 32% CD8+ and also 21% CD45RA+ and 39% CD45RO+. In the lymphatics, used to indicate lymphocytes emigrating from the tonsils, a different composition was found; e.g. many more T cells and three times more CD45RA+ than RO+ lymphocytes. Thus, HEV are not a selective entry site nor lymphatics an exit for specific lymphocyte subsets only, at least in these tonsils with chronic stimulation.

Adult↗

PubMed1999

[Dendritic cells, T- and B-lymphocytes and macrophages in supraglottic and glottic squamous epithelial carcinoma. Location and correlation with prognosis of the illness].

Dendritic cells play an important role within the mucosal immune system of the upper aerodigestive tract. They process exogenous and endogenous antigens and are able to induce a cytotoxic Tc/s lymphocyte reaction against tumors. Recently published data indicate that the in vitro application of tumor lysate incubated dendritic cells can provide a defense against melanoma. Before these new therapeutic strategies are available for the therapy of laryngeal cancer, basic studies have to be performed concerning the distribution of dendritic cells and other subpopulations, such as T- and B-lymphocytes and macrophages. In the present study the distribution of these subpopulations were examined within the epithelial and connective tissue compartments ("tumor front") of 20T2 squamous cell carcinomas of the supraglottis and glottis. The number of dendritic cells was compared with clinical parameters to check whether a high number of dendritic cells could be correlated with a better prognosis. In contrast to T-lymphocytes, results showed that dendritic cells were mainly located within the epithelial compartment of the tumors, their number ranging from 20 cells/mm2 to > 700 cells/mm2. By comparing each patient's clinical course with the number of dendritic cells, findings showed that those patients who died within the first postoperative year were characterized by a very small number of dendritic cells within their tumor tissue (< 100 cells/mm2). Although the number of patients was low, results indicate that a high number of dendritic cells within tumor tissue suggest a better prognosis.

Adult↗

PubMed1999

Acute laryngitis in the rat induced by Moraxella catarrhalis and Bordetella pertussis: number of neutrophils, dendritic cells, and T and B lymphocytes accumulating during infection in the laryngeal mucosa strongly differs in adjacent locations.

Infectious laryngotracheitis results in fulminant respiratory distress. During the disease, the subglottic mucosa is selectively infected and swollen, the reason for this preference being unknown. Therefore, in the present study the immunoreaction of the laryngeal mucosa was studied in the rat after inhalation of either heat-killed Moraxella catarrhalis (PVG rats) or application of viable Bordetella pertussis (BN rats). The number of neutrophils, macrophages, dendritic cells, and T and B lymphocytes was determined in the mucosa of the supraglottic, glottic, and subglottic area of the larynx as well as in the trachea. After application of the pathogens, the mucosa of the subglottic area was significantly more affected than the glottic mucosa. Already 1 h after application of M. catarrhalis, not only neutrophils but also dendritic cells and T and B lymphocytes were found both subepithelially and within the epithelium. They showed a similar kinetic progression, although at a different level. Two hours after application of M. catarrhalis, at the peak of inflammation, dendritic cells (173 +/- 10 cells/0.1 mm2) outnumbered neutrophils (54 +/- 9 cells/0.1 mm2), T lymphocytes (25 +/- 2 cells/0.1 mm2), and B lymphocytes (4.3 cells/0.1 mm2). The subglottic area (and the trachea) contained about three to five times more cells than the glottic area. In contrast, the number of local macrophages was lower in the subglottic area (24 +/- 5 cells/0.1 mm2) compared with that of the glottic area (38 +/- 6 cells/0.1 mm2), and did not change after application of both M. catarrhalis and B. pertussis. Thus, infectious laryngotracheitis in the rat closely resembles the clinical picture in children. In addition, the present results show a major difference in cellular influx in the mucosa of the glottic and subglottic area. This demonstrates that even in two closely adjacent locations, inflammatory responses of different magnitudes can occur, and it underlines the importance of regulatory mechanisms specific for the respective microenvironment.

Animals↗

PubMed1998

[Possible application of a signal enhancer for duplex ultrasound in otorhinolaryngology].

BACKGROUND: Vascularization is a characteristic of malignant tumor growth. It is possible to distinguish between benign and malignant tumors and lymph nodes of the head and the neck by their pattern of blood vessels which can be detected by color image ultrasonography. Unfortunately this detection is often unsuccessful because the vessels are too small. METHOD: Four cases (lymph node metastasis, chronic lymph node inflammation, Morbus Hodgkin, cancer of the floor of the mouth) are demonstrated. The vascularization of the masses was detected before and after the injection of Levovist, a contrast agent which is known to amplify the duplex signal up to 25 dB. RESULTS: In all of the demonstrated cases, a similar pattern of intranodal vessels was detected before the application of Levovist. After the injection an enhancement of the duplex signal could always be detected within the first minute and differences of the intratumoral pattern of the blood vessels between the cases could be identified. DISCUSSION: Levovist results in an increased detection of intratumoral blood vessels detected by color image ultrasonography. Further studies are necessary to check whether its application results in an increase of the specificity of the examination.

Adult↗

PubMed1998

[Topographic imaging of head and neck soft tissues by an new sectional imaging method in ultrasound diagnosis].

In contrast to CT and MRI, conventional B-scan echography is quick and easy to perform, cheap, and without side effects. The disadvantage is the limited field of view. This may result in a loss of information between the dynamic examination and the documentation. With SieScape a new technology was developed to address these problems. It allows one to obtain any imaging slices from the head and the neck. This technique is the first to allow a topographical orientation based on B-scan images. This study presents the application of SieScape, and demonstrates normal and abnormal findings. Initial experience with the new technology indicates that SieScape is an alternative to other methods such as CT and MRI.

Humans↗

PubMed1997

Long-term oral application of 5-bromo-2-deoxyuridine does not reliably label proliferating immune cells in the LEW rat.

To study the lifespan of immune cell populations in the LEW rat, 5-bromo-2-deoxyuridine (BrdU) was administered in the drinking water. After 12 weeks, the epithelium of gut and skin was completely BrdU+. In contrast, thymus, bone marrow, and germinal centers of Peyer's patches contained only a few BrdU+ cells, although most should have been labeled during this time. The lack of labeling was due neither to obvious toxic effects of BrdU on these organs nor to insufficient detection of incorporated BrdU. Analysis of the kinetic pattern of the appearance of BrdU+ cells in bone marrow, blood, spleen, and lymph nodes over 12 weeks revealed that the dosage of BrdU initially was high enough to label the proliferating cells in the bone marrow, but then became too low, although the BrdU uptake of the rats was similar over the entire time. This indicates that in the LEW rat the metabolism of orally applied BrdU changes over time, leading to a reduction in the amount of BrdU available for incorporation into the DNA below a level necessary for labeling all proliferating cells. This effect appears to be species- and strain-dependent, and should be considered when the BrdU technique is used.

Administration, Oral↗

PubMed1996

Distribution of immunocompetent cells in various areas in the normal laryngeal mucosa of the rat.

The larynx can be divided into a supraglottic, a glottic and a subglottic area, each serving different functions. In many cases of laryngitis the site of infection is located in one area, leaving other areas unaffected. It seems reasonable to speculate that the underlying cause of the heterogeneous infection pattern in the larynx is the different processing of infectious agents. Therefore, the number and distribution of granulocytes, macrophages, dendritic cells, natural killer cells and T and B lymphocytes in the normal laryngeal mucosa of young rats were studied. The results show that, with the exception of granulocytes, all subpopulations were present in different numbers. Many macrophages and dendritic cells but only a few natural killer cells and T and B lymphocytes were located in the mucosa. Dendritic cells, natural killer cells and T and B lymphocytes were rarely present in the vocal fold area, whereas in the subglottic area they were present in high numbers. Thus, differences in the composition of immunocompetent cell populations between laryngeal areas were detectable.

Animals↗

PubMed1996

Age dependency of the composition of immunocompetent cells and the expression of adhesion molecules in rat laryngeal mucosa.

Clinical evidence shows that laryngeal infections in infants differ significantly from those in adults. Therefore, the composition of the mucosal immune system (granulocytes, macrophages, dendritic cells, natural killer cells, and T and B lymphocytes) and the epithelial expression of class II-MHC molecules and adhesion molecules ICAM-1, VCAM-1, and E-selectin were studied in the larynx of newborn, 5-week-old, and 3-year-old rats. With the exception of macrophages, the immunocompetent cells began to immigrate into the laryngeal mucosa after birth, indicating that the laryngeal mucosa in newborn rats is immature. In contrast, ICAM-1 was already expressed. The number of immunocompetent cells and the expression of epithelial class II-MHC and ICAM-1 increased with age. Immunocompetent cells and epithelial class II-MHC and ICAM-1 expression were mainly detected in the subglottic region, but were almost absent in the vocal fold region.

Aging↗

PubMed1996

The mucosa of the middle ear and Eustachian tube in the young rat: number of granulocytes, macrophages, dendritic cells, NK cells and T and B lymphocytes in healthy animals and during otitis media.

To gain a better understanding of immune reactions during otitis media, the middle ear and Eustachian tube mucosa were studied as a unit in young rats with respect to the composition of immunocompetent cells before and after middle ear infection via the tube. Using immunohistology, the distribution of NK cells, important for the defence against viral antigens, and of dendritic cells, known to be most capable of antigen uptake, processing and presentation, was determined. Furthermore, the composition of cells of the unspecific immune system (i.e. granulocytes and macrophages) and the specific immune system (i.e. T and B lymphocytes) was studied. Macrophages and dendritic cells were spread over the whole middle ear mucosa, whereas only few NK cells and T and B lymphocytes and almost no granulocytes were detected. In the Eustachian tube mucosa, immunocompetent cells, with the exception of dendritic cells and macrophages, were only rarely seen. After induction of otitis media by severing the soft palate, immunocompetent cells increased in both the middle ear and Eustachian tube mucosa, but surprisingly they were almost absent from the area of the tubal orifice to the middle ear. The results indicate that immune reactions take place similarly in the Eustachian tube and in the middle ear mucosa.

Animals↗

PubMed1994

[Differential diagnosis of bluish red tumors of the posterior intact tympanic membrane].

Middle ear tumours may be seen frequently as bluish-red masses behind an intact tympanic membrane. In these cases all modern methods of visualisation such as CT or NMR are required for correct diagnosis and for planing adequate treatment. Most frequent are glomus tumours, either of the glomus tympanicum or the glomus jugulare. However, differential diagnosis must be considered, e.g. a tumour in the lower parts of the tympanon. In very rare cases the internal carotid artery takes an abnormal course, running free through the middle ear and touching the tympanic membrane. More often, granulomas or other inflammatory processes may be seen through a transparent ear drum. Haemangiomas or--of course--malignant tumours must be kept in mind. The role of modern radiographic methods is described in this paper, including some of the differential diagnoses mentioned above, with special reference to a case of carotid artery anomaly.

Adult↗

PubMed1993

[Radical parotid surgery of metastatic malignant melanoma].

With an increasing incidence of the malignant melanoma we also have to expect an increasing number of metastases of the parotid lymph nodes. Up to now there are no definite guidelines concerning the surgical treatment of these metastases. What is important is the question whether the facial nerve should be resected or retained. Between 1987 and 1991 in the ENT-clinic of the University Hamburg-Eppendorf eight patients were treated for metastases of a malignant melanoma in the parotid gland. The clinical course demonstrates that there is no indication for a radical surgical treatment of these patients. It neither leads to a delayed appearance of distant metastases, nor does it improve the life expectancy.

Adult↗