Biomedical subjects

C Reisser

Publications and source records attributed to C Reisser.

At least 19 recordsLinked to original sources

PubMed2001

A new clinical classification for Usher's syndrome based on a new subtype of Usher's syndrome type I.

OBJECTIVES: Usher's syndrome is an autosomal recessive disorder characterized by sensorineural hearing loss and progressive visual loss secondary to retinitis pigmentosa. Usher's syndrome is both clinically and genetically heterogeneous. Three clinical types are known today. METHODS: We conducted a study on 74 patients with Usher's syndrome, performing complete audiological and neurotological examinations. RESULTS: Twenty-six patients had total profound hearing loss and retinitis pigmentosa (Usher's syndrome type I), and 48 patients had moderate to severe sensorineural hearing loss and retinitis pigmentosa (Usher's syndrome type II). We identified 9 of the 26 Usher's syndrome patients with profound hearing loss who showed a normal response to bithermal vestibular testing. CONCLUSIONS: The combination of profound hearing loss and normal response to bithermal vestibular testing has not been previously described in Usher's syndrome. Therefore we describe a new subtype of Usher's syndrome type I and suggest a modified clinical classification for Usher's syndrome.

Adult↗

PubMed1999

Expression of facilitative glucose transport proteins during development of squamous cell carcinomas of the head and neck.

Positron emission tomography studies on malignant head and neck tumors have shown that tumor growth and elevated glucose uptake are associated. On a molecular level, glucose uptake is mediated by specific glucose transport proteins, which exhibit an altered expression in head and neck malignant neoplasms. However, it is unknown when during development of squamous cell carcinomas an alteration of the expression of glucose transport proteins occurs. We have studied the expression of different facilitating glucose transport proteins (GLUT 1, 2, 3 and 4) by immunohistochemistry in a variety of preneoplastic and neoplastic mucosal lesions of the head and neck. We have observed weak expression of GLUT 1 in normal mucosa, a marked expression of GLUT 1 throughout preneoplastic lesions, which correlated well with the degree of dysplasia. In squamous cell carcinomas of the head and neck (HNSCC) and metastases, GLUT 1 was always expressed strongly. In contrast, GLUT 2, 3 and 4 were not detected in any of the epithelial tissues examined. The increased expression of GLUT 1 in dysplastic lesions and its sustained expression in SCC indicate that changes of GLUT 1 expression are early events during development of HNSCC. Therefore, the detection of GLUT 1 might be a reliable marker in the diagnosis of premalignant lesions of the oropharyngeal mucosa.

Aged↗

PubMed1999

[Megadolichobasilar artery as the etiology of sensorineural deafness in differential sudden deafness diagnosis].

The megadolichobasilar artery is a rare vascular anomaly that can cause a variety of clinical symptoms but is usually asymptomatic. Not much attention has been given as yet to a possible sensorineural hearing loss caused by a megadolichobasilar anomaly. Vascular compression of the vestibulocochlear nerve must be assumed to be the pathogenic factor. The megadolichobasilar anomaly represents a rare entity in the differential diagnosis of sudden idiopathic sensorineural hearing loss. More common causes are acoustic neuromas, monosymptomatic Menière's disease and rupture of the round window membrane. We present the case of a 71-year-old white male in whom magnetic resonance angiography combined with contrast-enhanced computed tomography in three-dimensional reconstruction eventually led to the diagnosis of megadolichobasilar anomaly. The combination of both imaging techniques may be required for the effective diagnosis of similar vascular anomalies.

Aged↗

PubMed1999

[Functional expression of vascular endothelial growth factor receptor Flt-1 on squamous cell carcinoma of the head and neck].

Vascular endothelial growth factor (VEGF) is one of the most potent factors in tumor-induced neoangiogenesis. After binding to its specific receptors KDR and FLT-1 on the endothelial cell surface cell proliferation and migration are stimulated. Recently there has been some evidence for the expression of these receptors on tumor cells. We investigated the protein and mRNA expression of KDR and FLT-1 in native tissues and tumor cell cultures from squamous cell carcinomas of the head and neck (HNSCC) and analyzed their in vitro functional significance for tumor cell proliferation and migration. Apart from the expected expression of VEGF receptors on endothelial cells we observed a tumor cell-specific localization of FLT-1 in 29 tumors and KDR in 16 of 37 tumors analyzed. Functional studies in vitro revealed that the addition of VEGF to HNSCC cells inhibited the proliferation and migration of these cells in a dose-dependent manner. Our data suggest a potential negative regulatory loop for VEGF and FLT1 when tumor cells have an insufficient blood supply.

Biopsy↗

PubMed1999

[Glucose uptake in malignant tumors of the head and neck].

Positron emission tomography (PET) studies have shown an elevated glucose uptake in squamous cell carcinomas of the head and neck (HNSCC). On a cellular level glucose uptake is mediated by specific glucose transport proteins. We have used immunohistochemistry ot study the expression of different facilitative glucose transport proteins (GLUT) in the normal mucosa and in HNSCC. A weak expression of GLUT 1 was observed in epithelial cells of the normal mucosa. However, the expression of GLUT 1 was strongly elevated in epithelial cells of HNSCC. GLUT2, 3 and 4 were not detected in any of the epithelial tissues examined. An increased expression of GLUT 3 was found in inflammatory cells. The storage of glycogen showed a negative correlation to the GLUT 1 expression. While an increased glycogen storage was accompanied by a decreased GLUT 1 expression in highly differentiated epithelial cells, glycogen loss was associated with a strong GLUT 1 expression in less differentiated cells. The present study with PET indicates that the elevated glucose uptake of HNSCC is closely related to an increased expression of GLUT 1 in epithelial tumor cells.

Adult↗

PubMed1999

[Expression and localization profile of tenascin in squamous cell carcinomas of the head and neck].

Tenascin is a glycoprotein of the extracellular matrix and is mainly expressed in association with a high proliferative and migratory activity. This characteristic has made it a successfully used target molecule in the treatment of glioblastoma. An application of anti-tenascin therapy concept in squamous cell carcinomas of the head and neck (HNSCC) mainly depends on the expression pattern of tenascin in a tumor type. In the present study, we analyzed the messenger (m) RNA and protein expression of tenascin in HNSCC tumors when compared to normal mucosa and determined its cellular localization and correlation with various clinical parameters, including tumor staging. In native tissue tenascin protein was localized in the entire extracellular matrix surrounding the tumor. Normal mucosa showed only a weak and interrupted basement membrane staining. In situ hybridization revealed a very faint tenascin mRNA signal in basal cells of normal mucosa and a strong signal in tumor cells. This tumor cell-specific expression of tenascin was confirmed at the protein level in HNSCC cultures. However, there was no correlation of tenascin expression with tumor staging or tumor cell proliferation. Our data clearly show that tenascin is selectively expressed in HNSCC and therefore could be useful for a therapeutic intervention in these tumors.

Carcinoma, Squamous Cell↗

PubMed1999

[Uncommon sonographic findings of an epidermoid cyst in the head and neck].

Epidermoid cysts are rare lesions in the head and neck. Most often the are located in the submental region, although they sometimes can impose certain diagnostic problems. We report the case of a 19-year-old girl who presented with a fluctuant, painless, midline swelling of the floor of her mouth that had persisted for three months. Ultrasonographic examination showed a 5 x 5 x 4 cm cystic tumor with the unusual aspect of multiple smaller spherical formations. The differential diagnosis of the lesion included dermoid cysts, epidermoid cysts, ranula and parasitic lesions. Computed tomography and magnetic resonance tomography were not diagnostic. The patient underwent excision of the lesion, during which the cyst was completely removed. Histopathological diagnosis was consistent with an epidermoid cyst. The striking sonographic aspect of multiple spherical formations in the lesion was caused by multiple spherical keratin formations.

Adult↗

PubMed1999

[Cytokine expression of transforming growth factor-beta2 and interleukin-10 in squamous cell carcinomas of the head and neck. Comparison of tissue expression and serum levels].

Transforming growth factor-beta (TGF-beta) and interleukin 10 (Il-10) are cytokines that have a strong immunosuppressive ability. Their secretion by tumor cells is able to suppress an immunological response against tumor. Both factors have been shown to enhance tumor growth in glioblastomas and carcinoma of the breast. We determined the expression pattern of TGF-beta and Il-10 in squamous cell carcinomas of the head and neck (HNSCC) and a possible association with tumor stage and their pre-treatment cytokine serum levels. Cytokine expression in primary tumors and metastases of 21 patients with HNSCC was investigated by immunohistochemistry. To assess the TGF-beta2 and Il-10 levels in tumor patients before therapy 49 serum specimens were analyzed by ELISA. TGF-beta2 was detected in 95% of all tumor tissues analyzed and Il-10 in 79% of all tumors. TGF-beta2 was localized in tumor cells and tumor borders, while Il-10 was preferentially found in peritumoral connective tissue. Metastasizing tumors showed elevated pretreatment serum levels for TGF-beta2 and Il-10. There was no correlation between TGF-beta2 and Il-10 expression in tumor tissue and pretreatment serum levels. Our data show that the majority of HNSCC analyzed express TGF-beta2 and Il-10. A correlation between pretherapy elevated cytokine serum levels and tumor grade was shown.

Biopsy↗

PubMed1999

Expression and functional significance of vascular endothelial growth factor receptors in human tumor cells.

Vascular endothelial growth factor (VEGF) is one of the key factors in tumor neoangiogenesis, acting through its receptors KDR (VEGFR-2) and fit-1 (VEGFR-1) expressed on endothelial cells. Our data demonstrate that VEGFR-1 and to a lesser extent VEGFR-2 are expressed in a number of human tumor tissues and derived cells in culture. VEGFR-1 protein is expressed in 26 of 42 glioma tissues, 22 of which show a coexpression of VEGFR-1 with VEGFR-2; 1 glioma tissue expresses exclusively VEGFR-2. In the derived glioma cell cultures, we found VEGFR-1 mRNA expression in 6 of 11 cultures, with one coexpressing VEGFR-1 and VEGFR-2. Of four established glioma cell lines, two expressed VEGFR-1. In addition VEGFR-1 protein expression was demonstrated in 30 of 37 tumor tissues of squamous cell carcinomas of the head and neck, with VEGFR-2 coexpression in 15 tissues and an expression of VEGFR-2 alone in 1 tissue. Derived tumor cell cultures showed mRNA expression of VEGFR-1 alone in seven of seven cases. Established melanoma cell lines expressed VEGFR-1 mRNA in four of five lines, with VEGFR-2 coexpression in two lines. Concerning the functional significance of VEGF receptor expression, VEGF treatment of VEGFR-1-expressing tumor cells induced the inhibition of cell proliferation by 25 to 55% and the inhibition of tumor cell migration by 29 to 55%. Thus our data indicate that the coexpression of VEGF and VEGFR-1 in tumor cells could have an inhibitory effect on tumor cell proliferation and migration, a mechanism possibly induced as a response to a deficiency in nutrient and oxygen supply.

Base Sequence↗

PubMed1996

Three-dimensional computed display of otosurgical operation sites by spiral CT.

We studied the usefulness of spiral CT for preoperative information on the individual anatomy of the temporal bone in a computed three-dimensional (3D) display. In 87 patients with various otological diseases, 3D reconstructions were performed based on spiral high-resolution CT (HR-CT) by volume-rendering on an independent work-station. The positions of the ossicles, facial nerve, labyrinth and vestibular aqueduct relative to reference points were comprehensively demonstrated by thresholding or interactive segmentation. Spiral CT enables 3D display of otosurgical operation sites in a shorter scan time than conventional CT. 3D reconstructions improve the surgeon's understanding of individual anatomy and thus help in surgical planning. This is particularly important for surgery of temporal bone tumours, middle ear deformities, cochlear implants and saccotomy.

Ear Diseases↗

PubMed1996

Anatomy of the temporal bone: detailed three-dimensional display based on image data from high-resolution helical CT: a preliminary report.

Our purpose was to demonstrate the application of helical computed tomography (CT) for computer graphics of the normal temporal bone with special regard to inner ear structures. Three-dimensional reconstruction of temporal bones was performed from helical CT data on 41 patients with various otologic diseases. Image postprocessing was carried out on an independent work station. In contrast to former surface-rendered three-dimensional visualizations of the temporal bone, a volumetric-rendering algorithm was used. This technique allows automated segmentation, thresholding, and simultaneous visualization of different planes (cube-cutting) in near-real time. We were able to demonstrate the three-dimensional display of the labyrinth during clinical routine. Anatomic details (internal auditory canal, cochlea, vestibulum, semicircular canals, distal part of the vestibular aqueduct, complete ossicular chain, fallopian canal, internal carotid canal) were comprehensively demonstrated by interactive segmentation or thresholding. Difficulties were found in three-dimensional delineation of the complete vestibular and cochlear aqueduct, as well as the modiolus. Initial experience with an advanced helical CT-based three-dimensional display showed excellent images of temporal bone anatomy. Validation studies with correlative histologic sections and surgical dissections remain to be done.

Ear, External↗

PubMed1995

Chemotherapeutic management of head and neck malignancies with positron emission tomography.

OBJECTIVE: Antineoplastic chemotherapy in cases of nonresectable advanced malignancies of the head and neck can be very debilitating for the patient. For individual treatment planning, it is important to evaluate the early clinical effect of therapy. Morphological parameters, such as the size of the tumor and its relationship to adjacent structures, which can be determined by a number of imaging procedures, hardly reflect early therapeutic effects. Therefore, the metabolic activity of the tumor should be studied during antineoplastic therapy. DESIGN: Positron emission tomography was performed in 12 patients with metastasizing squamous cell carcinomas of the oropharynx, hypopharynx, and larynx before and after the first chemotherapeutic cycle. RESULTS: The fludeoxyglucose F 18 uptake was increased in all tumors and lymph nodes. In most lesions, an obvious response to treatment was observed after the first cycle of chemotherapy. However, differences in metabolic activity and changes in metabolism occurred during therapy. The treatment response varied in different lymph nodes in the same patient. There was a linear relation between metabolic change and growth rate during therapy, with different regression functions for tumors and lymph node metastases. CONCLUSIONS: Positron emission tomography provides absolute and comparable quantitative data on tumor metabolism before and after chemotherapy. It is therefore a useful method for observation and possible improvement of therapeutic measures in patients undergoing systemic chemotherapy.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed1995

[3-dimensional imaging of temporal bone structures using spiral CT. Initial results in normal temporal bone anatomy].

3D reconstruction of the temporal bone using spiral CT techniques was performed in 51 patients with various otological diseases during routine clinical work evaluation. The 3D display was optimized by a reduced study time and improved detail accuracy by special algorithms. We were able to demonstrate comprehensively in a 3D mode the normal anatomy of the inner ear and adjacent middle ear structures, such as the modiolus of the cochlea, the semicircular canals, the cochlear and vestibular aqueduct and the ossicles. We suggest routine 3D delineation of the substructures of the temporal bone prior to otologic surgery to provide the surgeon with a 3D view of individual anatomy and specific otosurgical sites.

Cochlea↗

PubMed1994

[Differential diagnosis of neck swelling due to suspected metastasis using positron emission tomography].

A noninvasive diagnostic method for the evaluation of a suspicious mass in the neck can be of great value for further diagnostic approach. The differing metabolic activity of malignant and benign tumors offers the possibility to determine the status of a lesion by the quantitative evaluation of the glucose uptake by positron emission tomography (PET). The diagnostic relevance of the metabolic activity has been shown earlier in more than 50 malignant tumors of the head and neck (Reisser et al., HNO 40 [1992] 225-231). The present study demonstrates the determination of tumor status in two benign and two malignant tumors of the neck by PET. Quantitative evaluation of the glucose uptake revealed significantly higher values in malignant than in benign lesions. Therefore the determination of the glucose metabolism prior to the indispensable histological diagnosis of the status of a lesion can provide valuable hints for the further diagnostic and therapeutic approach to the lesion.

Aged↗

PubMed1994

[Initial clinical experience with taurolidin instillation into the area of the middle area].

In this pilot study 2% taurolidin solution was used for irrigation of infected ears and instillation topically in 10 patients with severe purulent otitis media. The main purpose of the study was to find out whether the application of the taurolidin solution into the middle ear would cause significant pain or not. A slight increase in local pain was found sporadically but was not reason for withdrawing the drug. Twelve of 13 bacterial species isolated prior to treatment were eliminated during the trial, with the otorrhea of most patients stopping after just the first instillation. Audiometric evaluations during and 30 months after therapy did not reveal any ototoxic side effects. Tinnitus was not experienced by any patient during therapy. Overall findings demonstrated that local therapy with taurolidin for patients with severe purulent otitis media was very well tolerated and effective bacteriologically. There were also no therapy-related complications or ototoxic side effects.

Adult↗

PubMed1993

The relevance of positron emission tomography for the diagnosis and treatment of head and neck tumors.

A total of 48 patients with squamous cell carcinomas (SCC) of the head and neck were examined with positron emission tomography (PET) and 18Fluor-deoxyglucose (FDG). In 25 cases the FDG-PET-data were compared with flow cytometric data of the lesions to investigate the value of PET for the noninvasive determination of a tumor's proliferative activity. The quantitative analysis of the radioactivity concentrations revealed two groups of tumors with a different FDG-uptake. A correlation was seen between the proliferative index and the FDG-uptake with an r-value of 0.64 in the lower uptake group and an r-value of 0.81 in the higher uptake group. There was no correlation between any clinicopathological or morphological parameters of the tumors and the FDG-uptake. It is suggested that the different FDG uptake may correspond to differences at the molecular level. The PET-evaluation of therapeutic effects in patients with advanced SCC of the head and neck revealed different posttherapeutic changes of the metabolism in tumors and in lymph node metastases. Tumors were more sensitive to therapy than lymph node metastases. There was a high correlation between the growth rate and the change in FDG uptake with a different regression function for tumors and for lymph nodes. The data demonstrate the usefulness of PET and FDG for the evaluation of early therapeutic effects. Therefore PET can be applied for the treatment planning in patients with malignant tumors of the head and neck.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed1993

Fluorodeoxyglucose imaging of advanced head and neck cancer after chemotherapy.

Positron emission tomography (PET) was applied to evaluate therapeutic effects in patients with advanced head and neck cancer for use in monitoring therapy. In 18 patients with histologically proven head and neck cancer, PET studies with 330-440 MBq 18F-fluorodeoxyglucose (FDG) were performed prior to the first chemotherapeutic cycle with cisplatin and 5-FU. A second examination after the first chemotherapeutic cycle was performed in 11 patients. Tumor or lymph node volumes were determined from CT slices and the growth rate was calculated assuming an exponential function. Uptake in a region of interest was used for the quantitative evaluation of the PET images after standardization to injected dose and body weight. FDG data were available for 6 tumors and 10 metastases, volumetric data for 5 tumors and 7 metastases. One lesion showed an increase, seven a decrease in FDG uptake and eight lesions remained unchanged. Multiple lymph nodes in the same patient showed different baseline metabolisms and also different changes following therapy. Tumors were more sensitive to therapy than lymph node metastases. The growth rate and the change in FDG uptake were highly correlated with different regression functions for tumors and lymph node metastases. These data demonstrate that PET with FDG can be used to assess early chemotherapeutic effects. The information gained with PET can be included for treatment planning in patients undergoing systemic chemotherapy.

Adult↗

PubMed1992

[Ozena and allergic rhinitis in ichthyosis vulgaris].

The clinical course of an ozaena in a patient with an autosomal dominant ichthyosis vulgaris was complicated by the skin disease related atopic disposition with allergic rhinitis. Electron microscopic studies of the pathologically keratinized mucosa of the nasopharynx revealed a similar defect of the mucosal keratohyalin caused by the absence of the protein filaggrin.

Chromosome Aberrations↗