Biomedical subjects

A Dreher

Publications and source records attributed to A Dreher.

At least 19 recordsLinked to original sources

PubMed2004

[Respiratory sleep disorders: benefit from laser-surgery].

Laser-assisted surgery is a valid option for the treatment of respiratory sleep disorders and complements established therapies. Laser-surgery of the inferior turbinates can improve nasal obstruction and amend or eliminate primary snoring. LAUP is as well an ambulant therapeutic method for snoring, but it is leading to strong post-operative pain and should exclusively be applied to patients with small tonsils or who already underwent tonsillectomy. OSAS can be worsened by LAUP and should therefore be excluded before the operation. In childhood OSAS laser tonsillotomy leads to a distinct improvement of sleep-disordered breathing with normalisation of the sleeping profile; it is less painful than tonsillectomy and a part of the tonsil is left to continue to exercise its function in the immune system.

Adult↗

PubMed2001

[Obstructive sleep apnea syndrome. Which therapy for which patients].

Obstructive sleep apnea syndrome is defined by the American Academy of Sleep Medicine as a combination of at least five obstructive events per hour of sleep and such other symptoms as daytime sleepiness, ischemic heart disease and stroke. In addition to weight reduction, the use of oral appliances, and continuous positive airway pressure (CPAP), a number of surgical interventions such as uvulopalatopharyngoplasty and maxillomandibular advancement are also available for the treatment of sleep apnea. Since no prolongation of life has yet been shown for most of the therapeutic options, treatment needs to be individualized on the basis of symptoms, clinical findings and compliance.

Humans↗

PubMed2001

Analysis of the blind Drosophila mutant ninaB identifies the gene encoding the key enzyme for vitamin A formation invivo.

Visual pigments (rhodopsins) are composed of a chromophore (vitamin A derivative) bound to a protein moiety embedded in the retinal membranes. Animals cannot synthesize the visual chromophore de novo but rely on the uptake of carotenoids, from which vitamin A is formed enzymatically by oxidative cleavage. Despite its importance, the enzyme catalyzing the key step in vitamin A formation resisted molecular analyses until recently, when the successful cloning of a cDNA encoding an enzyme with beta,beta-carotene-15,15'-dioxygenase activity from Drosophila was reported. To prove its identity with the key enzyme for vitamin A formation in vivo, we analyzed the blind Drosophila mutant ninaB. In two independent ninaB alleles, we found mutations in the gene encoding the beta,beta-carotene-15,15'-dioxygenase. These mutations lead to a defect in vitamin A formation and are responsible for blindness of these flies.

Amino Acid Sequence↗

PubMed2001

Allergic rhinitis does not constitute a risk factor for obstructive sleep apnea syndrome.

Obstructive sleep apnea syndrome (OSAS) is a condition characterized by recurrent episodes of obstruction of the upper airway. The aim of this study was to evaluate whether nasal obstruction due to allergic rhinitis constitutes a risk factor for OSAS. Patients (n = 119) presenting typical symptoms of sleep apnea were tested for OSAS using polysomnography. Additionally all patients were tested in vivo and in vitro (including nasal eosinophilic cationic protein) for allergic rhinitis. Examination for allergic rhinitis revealed that 88.3% of all patients had no allergic rhinitis, whereas only 11.7% were diagnosed as allergic. No significant differences in sleeping parameters were observed between allergic and non-allergic patients. Comparison of parameters indicative of relevant OSAS (apnea-hypopnea index [AHI] > 10) revealed that 60% of non-allergic patients had relevant OSAS, compared to only 50% of allergic patients. Investigation of allergic subgroups revealed similar results: no significant differences in sleeping parameters or elevated rates of relevant OSAS parameters were observed, especially in perennial allergic rhinitis due to house dust mites. No elevated rates of allergic rhinitis were observed in the studied cohort of patients suffering from sleep apnea or OSAS. Furthermore, no significant differences in sleeping behavior or polysomnography parameters were found on comparing allergic and non-allergic patients. In summary, our data rule out allergic rhinitis as a major risk factor for OSAS.

Electroencephalography↗

PubMed2000

Relapsing polychondritis: a course over 20 years with cerebral involvement.

Relapsing polychondritis is a chronic inflammatory disease associated with an autoimmune disorder in cartilaginous tissue, eyes, labyrinth, blood vessels, and central nervous system. We describe a 75-year-old woman who presented with a 20-year history of dyspnea, inspiratory stridor, and polyarthritis. She developed dysmorphism of both ears and a saddle nose approximately 10 years earlier. Subsequently, she suffered from hearing loss and a tremor. A T2-weighted magnetic resonance imaging scan of the brain revealed multiple, spotted signal intensities. Immunohistochemical analysis of a serum sample showed antibodies to cartilaginous tissue, which were further identified on immunoblotting as antibodies to type II collagen. The extremely prolonged course of disease (>20 years) until a correct diagnosis was made is remarkable. Also, cerebral involvement, which was most likely caused by cerebral angiitis, and which, to our knowledge, has never previously been reported in this form, was detected. Arch Otolaryngol Head Neck Surg. 2000;126:1495-1498

Aged↗

PubMed1999

[Influence of nasal obstruction on sleep-associated breathing disorders].

BACKGROUND: The influence of nasal obstruction on sleep associated breathing disorders (SABD) and the controversial effects of surgical treatment are discussed. RESULTS: Complete nasal obstruction caused by nasal packing increases SABD, but varies from patient to patient and depends on age and individual anatomy. Especially patients with preexisting obstructive sleep apnea syndrome (OSAS) can develop severe complications. Some authors found a higher frequency of SABD in patients with nasal obstruction due to anatomical alterations, i.e. septal deviation, while others denied this connection. Major causes for the development of SABD in nasal obstruction include certain reflex mechanisms, increased negative inspiration pressure with a tendency for pharyngeal collapse, and transition to transoral breathing. Intermittent dilatation of the nasal valve using stents or tapes will lead to a decrease of nasal airway resistance and might also result in an improvement of SABD according to some studies, while others did not find any improvement. The results of controversial operative treatment in nasal airway obstruction are also described and include complete healing of high degree OSAS, improvement of sleep quality, and elimination of snoring. On the other hand, surgery might also be completely unsuccessful or even induce OSAS. CONCLUSION: As the effect of any kind of nasal operation on SABD is unpredictable from our present knowledge, the decision whether or not nasal surgery is indicated should depend on the individual situation of the patient. If OSAS is suspected, preoperative and post-operative polysomnography should be performed.

Humans↗

PubMed1998

[Basal cell adenoma of Weber's glands].

INTRODUCTION: In 1967, Kleinsasser first reported about basal cell adenomas in salivary glands, which represent approximately 1-2% of all salivary gland tumors. About 70% of these tumors are found in the parotid gland. Less often the minor salivary glands are involved, particularly in the upper lip region. We would like to report on a case of occurrence in the upper pole of the palatine tonsil. CASE REPORT: A 68-year-old woman was seen, who complained about a growth in her left tonsil. Other than a slow increase size, she had no symptoms. Examination revealed a solid tumor approximately 3 cm in diameter which displaced the upper part of the tonsil medially. In an MRI study, the neoplasia demonstrated a low signal intensity in the T1-weighted images and a high signal intensity in the T2-weighted images, which is relatively typical for a cystic structure. The tumor extended to the base of skull, and was completely resected by extended tonsillectomy. Histologic studies showed a cystic, regressive basal cell adenoma. DISCUSSION: When compared to pleomorphic adenomas, basal cell adenomas are relatively rare in the region of the soft palate. This case is especially interesting because we assume the origin of the tumor to be in the supratonsillar salivary glands (Weber's glands) and also because of the unusually pronounced cystic regressive changes.

Adenoma↗

PubMed1997

[HIV-associated non-Hodgkin's lymphomas (HIV-NHL) in the area of the head-neck].

The life span of HIV-infected patients has increased because of anti-retroviral therapy and improved means for treating opportunistic infections. However, HIV infection and subsequent immunosuppression result in an increased risk of high-grade B-cell lymphomas. The purpose of this study was to determine the incidence, localization, clinical features, therapy and survival time of patients with HIV-related lymphomas of the head and neck. Between 1988 and 1995, 280 HIV-infected patients presented with otolaryngologic symptoms. Seventy-two (25.7%) were found to have a neoplastic disease. Fifty-six of these patients (20%) were diagnosed as having Kaposi's sarcoma and 12 (4.3%) had lymphomas. According to the Kiel classification, lymphomas were subdivided into Hodgkin's disease (2 cases) and B-cell lymphomas of high-grade malignancy (10 cases). These latter cases were centroblastic (n = 4), Burkitt's type (n = 4), anaplastic large cell (n = 1) and not classifiable (n = 1). All patients with HIV-related non-Hodgkin's lymphomas (NHL) were men and 8 were homosexuals. The mean age was 36.1 years. In addition to 7 nodal locations, high-grade B-cell lymphomas were found in the oropharynx (n = 2) and palate (n = 1). Four patients underwent chemotherapy, 1 patient underwent radiation therapy and 2 were treated with both methods. Two patients did not receive any treatment and 1 patient underwent laser therapy. The survival time depended on the previous diagnosis of AIDS, the patients' immune status and the karnofsky index. In 2 patients the lymphoma led to the diagnosis of HIV infection. Our findings show that any solitary or enlarging tumors or ulcerating lesions in the head and neck region of HIV patients must be examined histologically to exclude HIV-NHL. We also recommend that young patients with high-grade B-cell lymphomas should undergo HIV screening.

Adult↗

PubMed1997

[Possibility for quantitative and frequency-specific assessment of auditory threshold with otoacoustic emissions].

BACKGROUND: Otoacoustic emissions can be used to study cochlear function in a non-invasive manner. They are an effective clinical tool for infant hearing screening. The purpose of this study was to determine their utility for a frequency-specific and quantitative estimation of the hearing threshold. METHODS: Transiently evoked otoacoustic emissions (TEOAE) and distortion-product emissions (DPOAE) were recorded from 16 normal and 86 hearing impaired ears and correlated with their hearing threshold between 0.5 and 6.0 kHz. RESULTS: The correlations of TEOAE and the hearing threshold ranged from 0.53 (0.5 kHz) to 0.69 (6.0 kHz), of the DPOAE from 0.51 (0.5 kHz) to 0.83 (6.0 kHz). Based on the optimal correlating OAE frequency we tried to predict the hearing threshold. We obtained 95% prediction intervals for TEOA between 19 dB (1.0 kHz) and 39 dB (4.0 and 6.0 kHz), for DPOAE between 21 dB (1.0) and 34 dB (3.0 and 4.0 kHz). CONCLUSION: Despite their clinically irrelevant greater prediction intervals at the low frequencies, our results suggest that DPOAEs are generally more valuable for the frequency-specific estimation of the hearing threshold. Prediction intervals may improve the interpretation of OAEs.

Adolescent↗

PubMed1997

Lethal tuberculosis in interleukin-6-deficient mutant mice.

Tuberculosis is a chronic infectious disease which causes major health problems globally. Acquired resistance is mediated by T lymphocytes and executed by activated macrophages. In vitro studies have emphasized the importance of macrophage activation for mycobacterial growth inhibition. In vivo, the protective host response is focused on granulomatous lesions in which Mycobacterium tuberculosis is contained. A cellular immune response of the T helper 1 (Th1) type is considered central for control of tuberculosis. Using interleukin-6 (IL-6)-deficient mice, we here demonstrate a crucial role of this pluripotent cytokine in protection against M. tuberculosis but not against Mycobacterium bovis BCG. Infection with M. tuberculosis was lethal for the IL-6-deficient mice at inocula that were still controlled by IL-6-competent mice. Spleen cells from M. tuberculosis-infected IL-6-/- mouse mutants produced elevated levels of IL-4 and reduced levels of gamma interferon compared to the control levels. Cytofluorometric analyses of spleen cells from M. tuberculosis-infected mice revealed more-profound alterations in T-cell ratios in IL-6-/- mice than in control mice. We assume that IL-6 contributes to host resistance by its proinflammatory activity and by its influence on cytokine secretion.

Animals↗

PubMed1997

[Extracranial schwannoma of the ENT region. Review of the literature with a case report of benign schwannoma of the base of the tongue].

BACKGROUND: Schwannomas are benign, usually solitary, encapsulated neoplasms which arise from the Schwann cells of the nerve sheath. They often originate from the VIIIth cranial nerve. Extracranially, about 25% of all Schwannomas are located in the head and neck. The lateral cervical region and the mouth are the most common sites. Schwannomas arising from the base of the tongue are very rare, and only a few cases have been reported so far. CASE REPORT: We add the case of a 31-year-old woman who had been suffering from slowly increasing dysphagia for about 4 years. Examination revealed a firm, smooth-shaped, nodular swelling about 3.0 cm in diameter arising from the base of the tongue. SYMPTOMS AND DIAGNOSIS: The symptoms of Schwannomas are nonspecific, and depend on size and location. Sonography, CT or MRI may be helpful for estimation of the tumor margins and infiltration of surrounding structures. To confirm the diagnosis, however, microscopic examination is necessary. Characteristic histological signs are the palisading of the spindle-shaped Schwann cells around the central acellular area (so-called Verocay bodies). THERAPY AND PROGNOSIS: The therapy of choice consists of surgical removal of the tumor; Schwannomas do not recur if they are completely removed. In contrast to multiple neurofibromas (von Recklingshausen's disease) Schwannomas almost never undergo malignant transformation.

Adult↗

PubMed1996

[Value of fat signal suppression MRI pulse sequences for diagnosis of malignant tumors in the area of the head-neck].

PURPOSE: Evaluation of frequency-selective fat saturation (FS) and short-tau inversion recovery (STIR) fat suppression (FU) in MRI of patients with malignant head and neck tumors. METHODS: Forty-five patients with biopsy-proven carcinomas of the extracranial head and neck were examined with MRI at 1.0 T. A T2-weighted TSE sequence with and without STIR-FU and a T1-weighted SE sequence with and without FS were compared in axial slices. RESULTS: STIR-FU was successful in all and FS in 85-88% of the head examinations (nasopharynx, sinuses, oropharynx, and oral cavity) and 33-46% of the neck examinations (hypopharynx and larynx). When visualization and delineation of tumors were ranked on a four-point scale (0-3), respective mean values for images with/without FU or FS were 2.6/1.9 for T2-TSE in all examinations, 2.2/1.7 (nasopharynx and sinuses) and 1.3/1.4-1.6 (oropharynx, oral cavity, hypopharynx, and larynx) for T1-SE without contrast media administration (CM) and 2.3/2.1 (nasopharynx and sinuses) and 2.4-2.5/1.9-2.0 (oropharynx, oral cavity, hypopharynx, and larynx) with CM. CONCLUSIONS: STIR-T2-TSE was a technically reliable pathfinder for localization and extension of both tumors and lymph nodes. FS-T1-SE was technically unreliable in examinations of the hypopharynx and larynx. With CM, FS-T1-SE was most useful for MRI of carcinomas of the oral cavity and oropharynx. In the nasopharynx and sinuses, T1-SE with CM and FS-T1-SE with or without CM were equal for tumor visualization and delineation.

Adipose Tissue↗

PubMed1996

Protein p60 participates in intestinal host invasion by Listeria monocytogenes.

The role of p60 in intestinal invasion by Listeria monocytogenes was assessed after oral infection of mice with the p60 low-expressing mutant RIII, or with anti-p60 antibody coated wild-type EGD. Invasion by L. monocytogenes RIII bacteria has been unimpaired suggesting that a low density of p60 suffices for entry. Up to 24 h post infection (p.i.), intestinal penetration by L. monocytogenes EGD bacteria was markedly reduced by coating with anti-p60 antibodies. In histological sections, anti-p60 antibody-treated L. monocytogenes EGD, but not uncoated listeriae were still detectable 24 h p.i. at the apical surface of enterocytes in the intestine. We conclude that p60 contributes to host invasion through the natural port of listerial entry, the intestinal epithelium.

Animals↗

PubMed1996

[Short tau inversion recovery fat suppression in T2-weighted turbo spin echo-MRI of malignancies of the mouth and oropharynx].

BACKGROUND: T1-weighted sequences before and after the application of contrast medium and T2-weighted sequences are used for magnetic resonance imaging of malignomas of the oral cavity and the oropharynx. The authors studied the utility of short tau inversion recovery fat suppression (STIR) in T2-weighted turbo spin echo sequences (TSE). METHODS: Twenty patients with malignomas of the oral cavity and oropharynx were examined on a 1.0 Tesla magnetom using T2-weighted TSE-sequences with and without STIR as well as T1-weighted spin echo sequences before and after the application of contrast medium. RESULTS: STIR was successfull in all patients. STIR worsened the signal-noise-ratio significantly, but improved tumor delineation compared to T2-TSE without fat suppression in 75% according to three different investigators. CONCLUSION: The STIR technique is beneficial for the progress in diagnostic imaging of cancer of the oral cavity and oropharynx.

Adipose Tissue↗

PubMed1996

[Cat scratch disease. An overview for the ENT physician].

BACKGROUND: Cat scratch disease (CSD) is a relatively common cause of chronic lymphadenopathy in the USA. In the present paper the authors describe recent advances in the understanding of this disorder focusing on etiology, clinical aspects, diagnostic management, and therapy. ETIOLOGY: Rochalimaea henselae and Afipia felis, two gram-negative bacteria, have recently been isolated from lymph node tissue of patients suffering from CSD. The current literature reveals that Rochalimaea henselae seems to be the most probable agent responsible for CSD. Serum samples from CSD patients' cats have shown titers of 1:64 or higher for antibodies to Rochallmaea henselae. EPIDEMIOLOGY: The incidence of CSD in the USA is between 0.77 and 9.3 per 100,000 per year. The incidence of CSD in Europe is unknown, but the prevalence of antibodies to Rochalimaea henselae among cats is comparable. CLINICAL MANIFESTATIONS: Most common symptoms of CSD are regional lymphadenopathy, fever, and malaise. Other manifestations occur in about 5% of patients and include encephalitis, granulomatous hepatitis, and Parinaud's oculoglandular syndrome. Fatal complications and irreversible sequelae have not been reported. DIAGNOSIS: To establish the diagnosis of CSD, the presence of regional lymphadenopathy, cat contact, and papula are required. Additional procedures include indirect fluorescent antibody assays and PCR. THERAPY: Up to now there is no standard therapy for CSD. Antibiotic treatment, however, might be considered for CSD patients with severe symptoms. Rifampicin, ciprofloxacin, trimethoprim sulfamethoxazole, and gentamicin are known to be effective antibiotic agents.

Adolescent↗

PubMed1996

Evaluation of TEOAE and DPOAE measurements for the assessment of auditory thresholds in sensorineural hearing loss.

Transiently evoked otoacoustic emissions (TEOAE) and distortion product otoacoustic emissions (DPOAE) can be quantified concerning their amplitude and frequency. They are known to be diminished or absent in sensorineural hearing loss. It is therefore of interest how TEOAE and DPOAE correlate with the auditory threshold and whether the auditory threshold can be predicted by these variables. In a cross sectional study of 61 patients (102 ears) with sensorineural hearing loss, auditory threshold, tympanometry, stapedius reflexes, TEOAE and DPOAE were measured. Correlation coefficients of the hearing loss (0.5-6 kHz) and the amplitude of the distortion product 2f1-f2 (0.46 4 kHz) respectively TEOAE amplitude (1-4 kHz) were computed. TEOAE showed lower correlation coefficients and less frequency specificity than DPOAE. In order to increase the correlations with the auditory threshold we fitted a multivariate linear regression model with TEOAE and DPOAE simultaneously as predictors for the auditory threshold gaining 95% prediction intervals of 19-39 dB depending on the frequency investigated. By restricting the hearing loss to a maximum of 70 dB HL the 95% prediction interval of the auditory threshold could be decreased to 18-26 dB. Further improvements can be expected if the high inter- and intraindividual variability of TEOAE and particularly DPOAE measurements can be reduced. The results allow us to use TEOAE and DPOAE in addition to click-evoked brainstem audiometry in order to provide more frequency specific information about the hearing loss in newborns, which is of the utmost importance for an ideal fitting of hearing aids.

Acoustic Impedance Tests↗

PubMed1995

Protective role of gamma/delta T cells and alpha/beta T cells in tuberculosis.

Tuberculosis is a chronic infectious disease which causes major health problems globally. Although acquired resistance crucially depends on alpha/beta lymphocytes, circumstantial evidence suggests that, in addition, gamma/delta T lymphocytes contribute to protection against tuberculosis. We have studied Mycobacterium tuberculosis infection in TcR-delta-/- or TcR-beta-/- gene deletion mutants which completely lack gamma/delta T cells or alpha/beta T cells, respectively. Low inocula of M. tuberculosis led to death of TcR-beta-/- mice and transient disease exacerbation in TcR-delta-/- mutants. Infection with higher inocula caused rapid death of TcR-delta-/- mice. The development of and bacterial containment in granulomatous lesions was markedly impaired in TcR-beta-/-, and less severely affected in TcR-delta-/- mutants. Mycobacteria-induced IFN-gamma production by spleen cells in vitro was almost abolished in TcR-beta-/- and virtually unaffected in TcR-delta-/- mice. Our data confirm the crucial role of alpha/beta T cells in protection against established tuberculosis and formally prove a protective role of gamma/delta T cells in early tuberculosis.

Animals↗

PubMed1995

[The MRT of malignant tumors of the oral cavity and oropharynx with frequency-selective and inversion-recovery fat-signal suppression].

PURPOSE: Evaluation of frequency-selective fat saturation (FS) and Short-Tau-Inversion-Recovery (STIR) fat suppression (FU) in MRI of patients with malignant tumours of the oral cavity or oropharynx. METHODS: Twenty patients with biopsy-proven squamous cell carcinoma of the oral cavity or oropharynx were examined by MRI at 1.0 T. A T2-weighted TSE-sequence with and without STIR-FU and a T1-weighted SE-sequence with and without FS were compared in axial slices. RESULTS: STIR-FU was successful in all and FS in 29/33 (87.9%) of the examinations. When visualisation and delineation of tumours were ranked on a four-point scale (0-3), respective mean values for images without/with FU or FS of 1.9 and 2.6 for T2-TSE, 1.4 and 1.3 for T1-SE without contrast media administration (CM) and 2.0 and 2.5 with CM were found. Signal/noise-ratios were inferior with FU and FS, but the tumour/muscle intensity ratio in CM-T1-SE improved with FS. CONCLUSIONS: STIR-T2-TSE and FS-T1-SE with CM were most useful for MRI of carcinomas of the oral cavity and oropharynx.

Adipose Tissue↗