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Biomedical subjects

M Quante

Publications and source records attributed to M Quante.

At least 19 recordsLinked to original sources
PubMed2006

Diagnostic adequacy and accuracy of fine needle aspiration cytology in neck lump assessment: results from a regional cancer network over a one year period.

AIM: To establish the diagnostic accuracy and adequacy of fine needle aspiration cytology (FNAC) within a regional cancer network, and to determine what service improvements may be required to allow successful implementation of an FNAC-based, 'one-stop' head and neck clinic, as proposed by the current National Institute for Clinical Excellence guidelines. MATERIALS AND METHODS: The Sussex cancer network serves a population of 1,200,000 and contains five hospitals within three acute trusts. In 2004, an audit was undertaken retrospectively to examine the diagnostic adequacy and accuracy of head and neck FNAC across the network. Comparisons were then made with the results of subsequent relevant surgery. For the purposes of the audit, FNAC was subdivided into three main groups: salivary gland, thyroid gland and neck node. As part of the data analysis, we also noted the clinical source of the FNAC and whether it was performed blind or under image guidance. RESULTS: In 2004, 712 FNAC procedures were undertaken in 647 patients, 276 of whom underwent subsequent surgery. Fine needle aspiration cytology was non-diagnostic in 52 per cent of patients in the neck node group, in 50 per cent in the salivary gland group and in 30 per cent in the thyroid group. With these non-diagnostic results removed, statistical analysis was performed on data from those patients who had undergone both FNAC and subsequent surgery. This gave a sensitivity of 89 per cent and a specificity of 57 per cent in the neck node group, a sensitivity of 64 per cent and specificity of 100 per cent in the salivary gland group, and a sensitivity of 62 per cent and specificity of 86 per cent in the thyroid group. Diagnostic problems with FNAC were noted, particularly in the differentiation of reactive nodal hyperplasia from lymphoma and in diagnosing follicular thyroid lesions. Ultrasound guidance was used in 50 per cent of the thyroid FNAC procedures but in only a minority of patients in the neck node and salivary gland groups. CONCLUSION: This audit demonstrated widespread diagnostic difficulties associated with head and neck FNAC in a large patient sample. It is likely that these problems will be mirrored in other cancer networks. In order for one-stop head and neck clinics to succeed, the non-diagnostic rate of FNAC in particular must be minimised. There are strategies to enable this, depending on local resources, including increased access to cytologists or cytology technicians, diagnostic ultrasound, image guidance for FNAC and the use of ultrasound-guided core biopsy.

Biopsy, Fine-Needle↗
PubMed2006

[Whole-heart coronary MR angiography -- initial results].

PURPOSE: To evaluate a new coronary MR angiography technique covering the whole coronary artery tree in one data set acquisition. MATERIALS AND METHODS: Six healthy volunteers and 15 patients with known CAD were examined with a navigator gated and corrected (NAV) free-breathing 3D steady-state free precession sequence covering the whole heart (WH-MRA) (TR = 5.4, TE = 2.7, SENSE factor = 2, 160 slices, 0.75 mm reconstructed slice thickness, in-plane resolution = 0.99 x 0.99 mm(2), scan time 14 min [50 % NAV efficiency]) and a vessel targeted 3D SSFP MRA sequence (t-MRA) (TR = 5.6 ms, TE = 2.8 ms, 20 slices of 1.5 mm reconstructed slice thickness, in-plane resolution = 0.99 x 0.99 mm(2), scan time = 7 min [50 % NAV efficiency]). Subjective image quality (4-point scale) and objective image quality parameters including vessel sharpness, vessel diameter and CNR were calculated for WH-MRA and t-MRA. In patients, the accuracy for detection of stenosis larger than 50 % was compared to the accuracy of X-ray coronary angiography (XA), which was considered the standard. RESULTS: WH-MRA demonstrated good vessel visibility in healthy subjects (100 %) whereas vessel visibility in patients was limited (78 % in an 8 segment evaluation). Vessel sharpness was inferior to that of t-MRA in patients (37 vs. 42 %) but equal in healthy subjects (42 %). Vessel diameter did not differ significantly between WH-MRA and t-MRA. CNR was significantly reduced for WH-MRA (CNR 7.4 vs. 11.5). The diagnostic accuracy for the detection of CAD was comparable for both MRA approaches (85.5 vs. 86.2 %). CONCLUSION: WH-MRA allows good coronary artery visualization in healthy subjects and patients and provides a simplified scanning procedure and advantages in 3D post-processing. Regarding image parameters and the detection of CAD, the results are comparable to those acquired with t-MRA. The major disadvantage remains the high number of diagnostically insufficient images.

Adult↗
PubMed2003

[Laser-evoked potentials: diagnostic approach to the dorsal root].

Functional diagnostics of the dorsal root are especially effective via nociceptive fibers on account of less intersegmental overlap compared to large-diameter fibers of the mechanoreceptive afferents. Laser-evoked potentials (LEP) are induced by short, painful heat stimuli. The aim of this work was to describe changes of the LEP in cases of dorsal root damage. The recorded LEP changes will be discussed with regard to their prognostic value as well as pathophysiologic aspects of dorsal root damage. Dorsal root function was tested in 21 patients suffering from clinically proven radiculopathy in one of the segments L4 to S1. Mechanosensibility and thermosensibility were clinically investigated. LEP were induced by slightly painful stimuli (80 on the affected and 80 on the contralateral unaffected dermatome). The LEP were evaluated by amplitude of the averaged electroencephalogram (EEG). In addition, a subjective pain rating was recorded after each stimulus. Investigation of dorsal root function by LEP in patients with radiculopathy yields two typical changes of the amplitude. On the one hand, there were significant reductions of amplitude, and on the other hand, a complete loss of LEP was found. LEP changes allow a graduation of patients who show no obvious differences in their clinical appearance. Which mechanisms are responsible as concerns deafferentiation and neuropathy of the dorsal root fibers are discussed. With regard to the LEP changes, a prognostic relevance in patients with dorsal root affections is likely. This question will be addressed in a prospective study soon.

Adult↗
PubMed2003

Single trial fMRI reveals significant contralateral bias in responses to laser pain within thalamus and somatosensory cortices.

Pain is processed in multiple brain areas, indicating the complexity of pain perception. The ability to locate pain plays a pivotal role in immediate defense and withdrawal behavior. However, how the brain localizes nociceptive information without additional information from somatotopically organized mechano-receptive pathways is not well understood. We used single-trial functional magnetic resonance imaging (fMRI) to assess hemodynamic responses to right and left painful stimulation. Thulium-YAG-(yttrium-aluminium-granate)-laser-evoked pain stimuli, without concomitant tactile component, were applied to either hand in a randomized order. A contralateral bias of the BOLD response was investigated to determine areas involved in the coding of the side of stimulation, which we observed in primary (SI) and secondary (SII) somatosensory cortex, insula, and the thalamus. This suggests that these structures provide spatial information of selective nociceptive stimuli. More importantly, this contralateral bias of activation allowed functionally segregated activations within the SII complex, the insula, and the thalamus. Only distinct subregions of the SII complex, the posterior insula and the lateral thalamus, but not the remaining SII complex, the anterior insula and the medial thalamus, showed a contralaterally biased representation of painful stimuli. This result supports the hypothesis that sensory-discriminative attributes of painful stimuli, such as those related to body side, are topospecifically represented within the forebrain projections of the nociceptive system and highlights the concept of functional segregation and specialization within these structures.

Adult↗
PubMed2002

Subcortical structures involved in pain processing: evidence from single-trial fMRI.

Pain is processed in multiple cortical and subcortical brain areas. Subcortical structures are substantially involved in different processes that are closely linked to pain processing, e.g. motor preparation, autonomic responses, affective components and learning. However, it is unclear to which extent nociceptive information is relayed to and processed in subcortical structures. We used single-trial functional magnetic resonance imaging (fMRI) to identify subcortical regions displaying hemodynamic responses to painful stimulation. Thulium-YAG (yttrium-aluminum-granate) laser evoked pain stimuli, which have no concomitant tactile component, were applied to either hand of healthy volunteers in a randomized order. This procedure allowed identification of areas displaying differential fMRI responses to right- and left-sided stimuli. Hippocampal complex, amygdala, red nucleus, brainstem and cerebellum were activated in response to painful stimuli. Structures related to the affective processing of pain showed bilateral activation, whereas structures involved in the generation of withdrawal behavior, namely red nucleus, putamen and cerebellum displayed differential (i.e. asymmetric) responses according to the side of stimulation. This suggests that spatial information about the nociceptive stimulus is made available in these structures for the guidance of defensive and withdrawal behavior.

Adult↗
PubMed2002

Painful stimuli evoke different stimulus-response functions in the amygdala, prefrontal, insula and somatosensory cortex: a single-trial fMRI study.

Only recently have neuroimaging studies moved away from describing regions activated by noxious stimuli and started to disentangle subprocesses within the nociceptive system. One approach to characterizing the role of individual regions is to record brain responses evoked by different stimulus intensities. We used such a parametric single-trial functional MRI design in combination with a thulium:yttrium-aluminium-granate infrared laser and investigated pain, stimulus intensity and stimulus awareness (i.e. pain-unrelated) responses in nine healthy volunteers. Four stimulus intensities, ranging from warm to painful (300-600 mJ), were applied in a randomized order and rated by the subjects on a five-point scale (P0-4). Regions in the dorsolateral prefrontal cortex and the intraparietal sulcus differentiated between P0 (not perceived) and P1 but exhibited no further signal increase with P2, and were related to stimulus perception and subsequent cognitive processing. Signal changes in the primary somatosensory cortex discriminated between non-painful trials (P0 and P1), linking this region to basic sensory processing. Pain-related regions in the secondary somatosensory cortex and insular cortex showed a response that did not distinguish between innocuous trials (P0 and P1) but showed a positive linear relationship with signal changes for painful trials (P2-4). This was also true for the amygdala, with the exception that, in P0 trials in which the stimulus was not perceived (i.e. 'uncertain' trials), the evoked signal changes were as great as in P3 trials, indicating that the amygdala is involved in coding 'uncertainty', as has been suggested previously in relation to classical conditioning.

Adult↗
PubMed2001

Anticoagulation: the present and future.

Thrombin is a central bioregulator of coagulation and is therefore a key target in the therapeutic prevention and treatment of thromboembolic disorders, including deep vein thrombosis and pulmonary embolism. The current mainstays of anticoagulation treatment are heparins, which are indirect thrombin inhibitors, and coumarins, such as warfarin, which modulate the synthesis of vitamin K-dependent proteins. Although efficacious and widely used, heparins and coumarins have limitations because their pharmacokinetics and anticoagulant effects are unpredictable, with the risk of bleeding and other complications resulting in the need for close monitoring with their use. Low-molecular-weight heparins (LMWHs) provide a more predictable anticoagulant response, but their use is limited by the need for subcutaneous administration. In addition, discontinuation of heparin treatment can result in a thrombotic rebound due to the inability of these compounds to inhibit clot-bound thrombin. Direct thrombin inhibitors (DTI) are able to target both free and clot-bound thrombin. The first to be used was hirudin, but DTIs with lower molecular weights, such as DuP 714, PPACK, and efegatran, have subsequently been developed, and these agents are better able to inhibit clot-bound thrombin and the thrombotic processes that take place at sites of arterial damage. Such compounds inhibit thrombin by covalently binding to it, but this can result in toxicity and nonspecific binding. The development of reversible noncovalent DTIs, such as inogatran and melagatran, has resulted in safer, more specific and predictable anticoagulant treatment. Oral DTIs, such as ximelagatran, are set to provide a further breakthrough in the prophylaxis and treatment of thrombosis.

Administration, Oral↗
PubMed1998

Epithelioid hemangioendothelioma presenting in the skin: a clinicopathologic study of eight cases.

Epithelioid hemangioendothelioma arising in the skin is extremely rare, and the majority of documented cases have developed in association with an underlying bone tumor. We report eight patients with an age range of 29-84 years (mean 53), who presented with primary cutaneous tumors at a variety of sites including the palm, shin, neck, knee, nose, back, and penis with a duration of between 6 and 12 months. Histologically, all eight cases presented as circumscribed nodules with an overlying acanthotic epidermis, three showing striking acrosyringeal proliferation, reminiscent of eccrine syringofibroadenoma. The tumors were composed of an admixture of slightly pleomorphic spindle and epithelioid cells with abundant, sharply defined eosinophilic cytoplasm and vesicular nuclei containing single nucleoli. Mitoses were generally sparse. All tumors showed intracytoplasmic lumina and intraluminal erythrocytes were occasionally apparent. The tumor cells were embedded in a myxoid or hyaline matrix. In contrast to visceral lesions, a vascular origin was not evident in any of our cases. The tumor cells variably expressed CD31, CD34, factor VIII-Rag, and smooth-muscle actin but not pankeratin or epithelial membrane antigen. Follow-up ranged from 4 months to 3 years. None of the lesions has thus far recurred and there have been no metastases.

Adult↗
PubMed1977

[Gentamycin in distributive balance between serum, perilymph and liquor in guinea-pig after dosage in therapeutical range (author's transl)].

Dosage of gentamycin in therapeutical range just as in higher doses results in a distributive balance between serum, perilymph and liquor under the condition of steady serum levels. After high doses the perilymph levels compared to the serum levels are relatively lower than after less doses. The distributive balance is reached after about 7 h in doses, which lead to concentrations of the serum levels of the supposed ototoxic critical range. Afterwards the concentration in the inner ear doesn't increase. In steady state, the concentration in serum is always higher than in perilymph, whereas the perilymph concentration is always higher than the one in liquor.

Animals↗
PubMed1977

[Is hearing of the students damaged by environmental noise in their leisure time? (author's transl))].

An examination of 1300 students between the ages of 10 and 20 who had not yet been exposed to industrial noise was performed in order to establish to what extent general environmental noise influences hearing. The fact that there was no age-dependent increase of high tone hearing loss, as well as the small correlation between hearing loss and total noise load are evidence that there is no hearing loss produced by increasing environmental noise exposure of teenagers in Germany. Middle ear infections, infections diseases and skull trauma are suggested as causes of the usually minimal high tone hearing losses.

Adolescent↗
PubMed1977

[Do neomycin ointment dressings damage the inner-ear when used in the external auditory canal or the radical mastoidectomy cavity? (author's transl)].

When in low concentration (0.38%) in an ointment base neomycin within the middle ear does not damage the inner ear. Animal experiments show that doses 10 times greater do not damage the hair cells, but when in aqueous solution all hair cells are destroyed. Many years experience has confirmed that neomycin ointment packing for postoperative ears and infected radical mastoid cavities does not produce inner ear damage. These patients have been carefully monitored by audiometry.

Animals↗
PubMed1976

[Observation of the course of leukoplakia in the Larynx (author's transl)].

During a period of 15 years biopsies of the larynx of 3000 patients were taken out. At 319 patients the first histodiagnosis "Leukoplakia" was made. 10% carcinomas were found out later on grounds of observation of the course and by letter. 7% of these carcinomas occured within 1 year after the first histodiagnosis of "Leukoplakia". The first biopsy of these 7% carcinomas diagnosed as a "Leukoplakia" must be interpreted as a biopsy out of the marginal area of an already existent carcinoma. 3% of the carcinomas developed from the "Leukoplakia" just in the following years.

Biopsy↗
PubMed1976

[ORL-symptomatology of "subclavian steal" syndrome].

A female patient with subclavian steal syndrome is presented in this paper. She was treated originally in the ORL department because of objective ear sensations and of Menière's disease. Otological symptoms of the steal effect, e.g. dizziness, uni- or bilateral internal ear disorders and tinnitus are discussed in view of literature data and of the case history. In the differential diagnosis of above symptoms the ORL physician should also consider subclavian steal syndrome

Adolescent↗
PubMed1976

[Diphtheria in the area of antibiotics (author's transl)].

In Düsseldorf repeated incidences of severe membranous angina were observed, several cases of which had a fatal outcome. Though the bacteriological proof could only be firnished in one case, in the rest of the cases there was also the strong suspicion of diphtheria. To guarantee the final diagnosis, it is necessary, to make the throat swab before the antibiotic therapy begins since only a single dosis of penicillin jeopardises the demonstration of the infection agent. It must urgently be minded of the necessity, that in cases of suspicion a diphtheria antitoxin should be given in good time, not waiting for the bacteriological clarification, since already a whole generation of physicians from their personal experience is no longer up to date on the clinical picture of diphtheria.

Adolescent↗
PubMed1976

[Therapeutic results in the treatment of otitis media in children with and without cleft palate (author's transl)].

Therapeutic results in the treatment of secretory otitis media were compared in children with and without cleft palate. The children were treated by the implantation of a ventilation tube. Pre- and postoperative data of a total of 551 patients were evaluated by a computer system. Following results were obtained: 1. Severity of change in the mean air-bone gap in patients with and without cleft palate was nearly the same. 2. The men airbone gap in both series after treatment showed no significant difference. 3. After evaluating impedance measurements, children without cleft palate showed a slight improvement of pressure patterns in the middle ear, on the contrary, children with cleft palate showed a significant pressure decrease. --Because of deterioration of pressure pattern in children with cleft palate, in spite of intensive treatment, implantation of a ventilatory tube for a longer period is necessary.

Child↗
PubMed1976

[Deafness due to topical neomycin (author's transl)].

Today neomycin is almost exclusively given as an ointment in combination with other antibiotics, because of its known oto- and nephrotoxicity. Topical application in high dosage can cause ototoxicity as proved by one patient from this clinic. After laryngectomy and neck dissection for an extensive carcinoma of the epiglottis a 2 X 2 cm dehiscent pyocyaneus infected wound was treated daily with neomycin sulphate solution. A total of 30 gm was given over 3 months during which time the patient became deaf neomycin caused the deafness.

Carcinoma↗
PubMed1976

The correlation between permanent septal deformities and nasal trauma during birth.

Both the outer and inner nose as well as the position of the parietal bones of 972 patients at an age of 3 to 82, were examined giving evidence of the configuration of the infant's head at birth and thereby of the "severity" of the birth. In comparison with the sectio-patients the configuration of the infant's head in the birth canal reveals statistically recorded deformations of the outer and inner nose with an obstruction of the nasal breathing in 20% of the patients examined. The degree of the configuration has a definite influence on the degree of the nose deformation. The adjustment of the rotary direction of the infant's head in the 1st and 2nd vertex presentation determines the direction of the nose deformation. The demand of many authors for an immediate rhinological examination and corrections in the newborn child, for instance on the septum, to be performed still in the obstetrical department, must due to our own examinations be advocated.

Adolescent↗