Multi-element analysis by inductively coupled plasma optical emission spectrometry of airborne particulate matter collected with a low-pressure cascade impactor.

A method was developed for the elemental analysis of size segregated particles ranging from 0.03 to 10 microns. Sampling and analysis problems are discussed in this paper. Particles were collected with a Dekati low-pressure cascade impactor. PTFE filters coated with oleic acid were used as substrate. Particles were microwave digested in closed vessels. The optimum digestion mixture was composed of HNO3 (1 mL), HF (50 microL) and H2O (1 mL). The optimal power setting and digestion time were studied in order to achieve an efficient digestion. A ca. 35 min microwave digestion cycle at a 650 W maximum power allowed complete digestion of the samples. Special emphasis was placed on the pressure in the closed vessels to avoid sample losses. Solution samples were analysed by inductively coupled plasma optical emission spectrometry using an ultrasonic nebuliser for 18 elements (Al, Ba, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, S, Sr, Ti, V, Zn). This procedure was tested with NIST Standard Reference Material 1648 Urban Particulate. Recoveries for certified elements ranged from 95 to 105% except for Al (90%). The influence of cascade impactor materials was investigated with 44 field samples. Strong artefacts due to contamination were shown for analysis at environmental concentrations of Al, Cr, Mn and Ni.

[Acoustic rhinometry for evaluating the effectiveness of antihistaminics]. / Die akustische Rhinometrie zur Beurteilung der Wirksamkeit von Antihistaminika.

Acoustic rhinometry is a unique non-invasive technique for imaging and measuring the free cross-sectional area of the main nasal cavity. By so doing, reactions of the mucosa can be assessed at any selected site in the nose. The goal of this study was to define the optimal conditions for the utilization of acoustic rhinometry to determine the ability of an antihistamine to alter the effects of histamine in the mucous membrane of the nose. In a group of 30 healthy volunteers subjectively normal nasal breathing, and no history of allergy, rhinometry was performed to measure the cross-sectional area in the region of the head of the inferior nasal concha at 0.5, 10 and 15 min after histamine provocation. The volunteers subsequently received cetirizine as antihistamine. Four hours later, rhinometry was repeated after administration of histamine via the contralateral nostril. Findings showed that conchal dilatation measured 10 min after provocation was statistically less severe in 63.3% of the patients treated with cetirizine. Compared to pretreatment values, the ventilated cross-sectional area became 45.6% larger after administration antihistamine. These findings demonstrated that the nasal swelling measured 10 min after antihistamine administration was due to the effects of histamine and was not due to tactile or physical stimuli. The present studies showed that the new measurement technique is precise and reproducible. These results have also demonstrated that a acoustic rhinometry permits an objective assessment of drug efficacy while making it possible to avoid the errors observed in other variable regions of the nose, such as the nasal isthmus or nasopharynx as well as errors associated with subjective scoring systems.

[Feasibility of the differential diagnostic imaging of neck lymphomas]. / Möglichkeiten der bildgebenden Differentialdiagnostik der Halslymphome.

In 51 patients with cervical swellings, pretherapeutic examinations by ultrasound, computed tomography (CT), and magnetic resonance imaging (MRI) were carried out for the confirmation of exclusion of cervical lymph node metastases. By use of the M/Q ratio and morphological criteria, it is possible with ultrasound to differentiate between relatively enlarged lymph modes and lymph node metastasis with a certainly of > 90%. This was only possible in CT after administration of contrast media and the success rate was lower (72%). Both by use of the M/Q ratio and contrast medium administration, MRI is able to distinguish between lymph node metastases and reactively altered lymph nodes. Differentiation between Hodgkin/non-Hodgkin lymphomas of the neck and reactively enlarged lymph nodes is also possible with the aid of the M/Q ratio. In such cases, sonography and MRI are superior to CT. A certain differentiation between lymph node metastases and Hodgkin/non-Hodgkin lymphomas is only possible in some cases. However, there are indicative criteria for differential diagnosis. A delineation between specific lymph node inflammations and glomus carotid tumors is also possible because of the differing take-up of contrast medium in CT and MRI and via doppler sonographic criteria.

[The value of magnetic resonance tomography and computed tomography in the tumor staging of laryngeal and hypopharyngeal carcinomas]. / Wertigkeit von Magnetresonanztomographie und Computertomographie im Tumorstaging des Larynx-/Hypopharynxkarzinoms.

43 patients with malignant tumours of the larynx or hypopharynx were examined by MRT and CT to compare their accuracy for T-staging. There was histological confirmation in all cases. Histological studies showed an accuracy in T-staging of 90% for MRT and 82% for CT. Differentiation between stages T2/T3 and T3/T4 is possible in most cases by either method. A source of error is the difficulty of differentiating oedema or inflammatory changes from tumour. This led to occasional overinterpretation of the T4 stage. Demonstration of cartilage involvement was easier with MRT (88%) than with CT (84%). The use of Gd-DTPA with T1 weighted and proton weighted sequences allows earlier diagnosis of cartilage invasion. Early cartilage involvement may be missed by CT when it is seen on MRT. In addition, the ability to produce coronal and sagittal images by MRT makes this superior to CT in judging tumour extension.

Olfactory evoked potentials and contingent negative variation simultaneously recorded for diagnosis of smell disorders.

Objective diagnosis of olfaction can be performed by registration of cortical olfactory evoked potentials (OEP) and of contingent negative variation (CNV). The CNV is a negative voltage developing at the vertex after discrimination of one of two smells while the patient is expecting a second stimulus. By an adequate procedure, including a long time window for averaging (2.56 seconds) with appropriate filters, the two tests can be performed simultaneously in a single session of less than 10 minutes. Anosmia is determinable by both OEP and CNV, although CNV shows less variability. On the other hand, CNV requires attention and some cooperation of the patient. Parosmia is accessible by CNV only; two odor qualities presented in random order have to be distinguished. Hyposmia can also be detected; just above the discrimination threshold, CNV amplitudes tend to be large--even enhanced--whereas OEP amplitudes may still be undetectable.

[The value of nuclear magnetic resonance tomography in tumor staging of laryngeal-/hypopharyngeal cancer]. / Wertigkeit der Kernspintomographie im Tumorstaging des Larynx-/Hypopharynxkarzinoms.

Twenty-four patients with tumors of the larynx and hypopharynx were examined with magnetic resonance imaging (MRI) and laryngoscopy. The results of MRI and laryngoscopy were then correlated with the pathology reports. Diagnostic findings of 84% of the MRI studies correlated with the pathology report, while laryngoscopy provided exact classification in 79%. MRI tended to overestimate tumor size because edema or inflammatory reactions of surrounding tissues simulated tumors. However, normal mucosa also enhanced contrast medium, restricting the value of this technique. Laryngoscopy tended to underestimate tumor size, because deep extensions of tumor and cartilage involvement were difficult to detect. Nonetheless, the utility of MRI in obtaining axial, coronal and sagittal slices was found to facilitate the preoperative staging of tumor extensions.

[Effect of decreased and lost high frequency hearing on latency of acoustically evoked brain stem reaction]. / Der Einfluss von Hochtonsenken und -abfällen auf die Latenz der akustisch evozierten Hirnstammreaktion.

The diagnosis of retrocochlear damage is supported by an increased latency difference between peak I and peak V. In case of high frequency hearing loss peak I is often hard to determine, and peak V latency may be shifted not only by neural delay, but also by missing basal hair cells. The amount of cochlear delay can be estimated by a procedure presented here. High frequency decay was simulated by steep high-pass noise masking. Peak V latency turned out to be established by the highest unaffected frequency components of the click stimulus. Thus, in case of a high frequency gap (with normalization towards higher frequencies) latency may be almost normal. In case of prolonged latency the amount ascribable to the cochlea may be rather precisely be estimated. If the whole lag is explained this way, unnecessary further diagnostics can be avoided.

[Computed tomography: the TNM staging of laryngeal carcinoma]. / Computertomographie: TNM-Staging des Larynxkarzinoms.

In 64 patients with malignant lesions of the larynx, CT and microlaryngoscopy (ML) were evaluated in terms of T-staging. Histological information was present in all cases following operation. CT showed an accuracy of 90% in T-staging. ML showed an accuracy of only 71% of correct T-staging. CT is superior to ML particularly in distinguishing between stages T3 and T4 and T1 and T2. CT tends to overestimate tumour stage whereas ML tends to underestimate it. CT was also compared with palpation and sonography as regards N-staging. In this respect sonography has the highest accuracy (94%) followed by palpation (76%) and CT (74%).

[Cervical lymph node metastases. The sonographic demonstration of malignancy]. / Halslymphknotenmetastasen. Sonographischer Malignitätsnachweis.

The value of sonography for demonstrating cervical lymph node metastases has been studied, using longitudinal and transverse measurements as criteria for malignancy. A transverse/longitudinal quotient greater than 2 indicates the presence of metastases with a 96% assurance. Using only longitudinal measurements lymph node metastases can be excluded with only a 36% assurance. The sensitivity of both methods also differs (95% for the maximal transverse quotient as against 90% for longitudinal measurements). The use of the maximal transverse quotient increases specificity from 36 to 96%. This gives sonography an accuracy of 95%.

[A histologically controlled study of the value of sonography and palpation for the detection and exclusion of neck lymph node enlargements and metastases]. / Histologisch kontrollierte Studie zur Wertigkeit der Sonographie und der Palpation zum Nachweis und Ausschluss von Halslymphknotenvergrösserungen und -metastasen.

Preoperative evaluation of cervical lymph nodes by ultrasound and palpation was compared retrospectively in 123 patients with tumours on the head and neck. The diagnostic accuracy was higher by ultrasound (96.5%) than by palpation (85.5%). Hence, the sensitivity for detecting cervical metastases was also higher for ultrasound than for palpation (96% versus 83%), because of the reduced false negative findings. Specificity, however, was higher for palpation (82%) than for ultrasound (74%). Ultrasound was superior in delineating the relationship of metastases to adjacent tissues (vessels). Major disadvantages of ultrasound were the higher percentage of false positive findings (26%) and absence if delineation of the relationship to bony structures.

[Cervical lymph node metastasis: significance of computerized tomography and palpation. A histologically controlled comparison]. / Halslymphknotenmetastasen: Wertigkeit von Computertomographie und Palpation. Ein histologisch kontrollierter Vergleich.

Palpation and CT are used before treatment, in addition to sonography, in patients with tumours in the head and neck for lymph node staging. The accuracy of CT in identifying lymph node metastases is 79% and in our clinical material is similar to the accuracy of palpation (81%). Sensitivity of CT (93%) is better than palpation (82%). Specificity of CT (65%) is less than that of palpation (82%). The high percentage of false positives from CT (35%) is due to enlargement of the lymph nodes resulting from sinus histiocytosis or follicular hyperplasia. CT is significantly superior to palpation in demonstrating the relationship of the lymph nodes to the surrounding tissues (vessels, muscles, bones).