New methods for fast on-site measurement of odorous compounds.

New methods for measurement of odorous gases, especially for aerosol-bound chemical compounds, have been developed in the Department of Measurement Technology (Technical University of Hamburg Harburg--MT-TUHH). Odorous compounds in the waste gases produced by the food industry were analysed based on high-volume aerosol sampling techniques, enrichment on solid phase micro extraction (SPE) cartridges and analytical measurement techniques using thermal desorption gas chromatography-mass spectrometry. The analysis results were compared to classic analytical procedures using adsorbence materials (Tenax) for enrichment. In comparison to aerosol sampling, analysis of Tenax samples was found to be ineffective, especially for analyzing polar semi volatile compounds. In addition, sensor arrays were also used in the study to characterize odors of different waste gases emitted by food production facilities. Measuring the odor units of the waste gas of a fat producing factory, the results of sensor-array-measurements show good correlation with results obtained with olfactometric measurements.

Comparative clinical studies of ototoxicity and nephrotoxicity of amikacin and gentamicin.

A comparative study of the oto- and nephrotoxicity of amikacin and gentamicin was carried out prospectively. Twenty-six gentamicin-treated patients and 27 amikacin-treated patients were monitored for changes in auditory and renal function during and after therapy. Thirteen of those treated with gentamicin and 20 of those treated with amikacin underwent vestibular caloric testing which could be evaluated for evidence of toxicity. In four (15.4%) of the gentamicin-treated patients, nephrotoxicity developed; no such toxicity was seen in the amikacin-treated patients. This difference may have been due to a fortuitously higher incidence of pretreatment renal impairment in the gentamicin-treated group. In two gentamicin-treated patients (7.7%), ototoxicity developed (one auditory, one vestibular), and in two amikacin-treated patients (7.4%), auditory toxicity developed. Statistical analysis of oto- and nephrotoxicity and their risk factors was not attempted because of the small numbers of patients who could be evaluated. Additional patients are being studied.

Comparative study of ototoxicity and nephrotoxicity in patients randomly assigned to treatment with amikacin or gentamicin.

Fifty-four patients treated with gentamicin and 52 patients treated with amikacin were evaluated for nephrotoxicity and ototoxicity in a prospective, randomized, blinded comparative trail. According to our definition of nephrotoxicity (an increase in serum creatinine levels to at least 50 percent and 0.5 mg/dl above the baseline value), nephrotoxicity occurred in eight (15 percent) of the patients who were treated with gentamicin and none of the patients who were treated with amikacin (p = 0.006). Using several other definitions of nephrotoxicity, the differences in incidence between the treatment arms were not significant. Nephrotoxicity appeared to be associated with impaired baseline renal function, greater age, and the presence of bacteremia. Ototoxicity occurred in six (11 percent) of the 54 gentamicin-treated patients; auditory toxicity occurred in three patients, and toxic changes were observed in three of the 33 patients who could also be evaluated for vestibular toxicity. Similarly, ototoxicity was observed in seven (13 percent) of the 52 amikacin-treated patients; auditory toxicity occurred in four patients, and of the 34 patients who could also be evaluated for vestibular toxicity, three exhibited vestibular toxicity without auditory toxicity are one experienced vestibular effects in addition to those affecting the cochlea. We observed a modest association of ototoxicity with nephrotoxicity and with an elevated mean trough aminoglycoside serum level. The results of this study indicate that amikacin may be less nephrotoxic than gentamicin in humans; however, the broad applicability of this finding to other patient populations is uncertain.

The ototoxic effects of ethacrynic acid in man and animals.

A review of the literature was carried out to summarize the ototoxic effects of ethacrynic acid on man and animal. The effects of this drug on the electrolytes of the endolymphatic and perilymphatic systems, on the cochlear potentials and the auditory cortical-evoked responses, were reviewed. Histological animal studies determined by light and electron microscopy were described. Potentiation of this drug with previous aminoglycoside therapy was discussed. In this paper, a human case report with temporal bone findings was present in addition to the histopathological effects of this drug which were shown in a series of animals receiving this drug over a period of time. Edematous and cellular changes in the stria vascularis, especially with animals receiving large doses of the drug, were described. No permanent alterations in the cochlear potentials resulted from the long-term therapy with ethacrynic acid.

Quantitative study of vestibulotoxicity induced by gentamicin or cisplatin in the guinea pig.

Although aminoglycoside vestibulotoxicity is well established, the question of cisplatin vestibulotoxicity is controversial. The goals of this study were 1. to determine whether cisplatin induces vestibulotoxicity as measured histologically, and 2. to compare the vestibulotoxicity between gentamicin and cisplatin. Guinea pigs' vestibular end-organ hair bundles in control, gentamicin, and cisplatin groups were compared. In the lateral cristae of the cisplatin group, hair bundles decreased 21% on the central apex portion. In the gentamicin group, a slight decrease (17%) of hair bundles on the striola from the utricular maculae was observed, as was severe damage on the entire cristae, especially on the central apex (70%). These results indicate that gentamicin and cisplatin may not influence vestibular function of the otolithic membrane. However, gentamicin may severely damage and cisplatin may slightly damage the crista ampullaris hair bundles.

Sequential combination chemotherapy for advanced squamous cell carcinoma of the head and neck.

Thirty-four patients with advanced squamous cell carcinoma of the head and neck have been treated with sequential combination chemotherapy consisting of Cytoxan, methotrexate, oncovin, bleomycin and adriamycin, followed by Leucovorin (COMBAL). All patients had undergone extensive prior radiation and/or surgery. All the patients had recurrent cancer. Toxicity included two deaths from drug induced pancytophenia and one from sepsis. Treatment was well tolerated and could be given in the outpatient clinic. No bleomycin pulmonary or adriamycin cardiac toxicity was seen. Results include 4 patients who achieved complete remission, objective improvement in measurable lesions in 6 others, stabilization of disease for 1 to 3 mo. in 5, and progression of disease in 13. Survival has ranged from 1 to 19+ months with a median of 10.7 mo. for patients that were evaluated. We conclude that COMBAL produces objective evidence of improvement in approximately 45% of patients with far advanced, previously treated squamous cell carcinoma of the head and neck.

Prediction of survival in head and neck cancer based on leukocyte sedimentation in Ficoll-Hypaque gradients.

A battery of immunologic tests were performed on 42 patients with recurrent cancer of the head and neck whose median survival time was 6.8 months. Two tests correlated with survival: total white blood cell (WBC) count and the percentage of lymphoid cells (%LG) in the Ficoll-Hypaque gradient separated leukocyte fraction of blood. Patients with abnormally low values of %LB had a poor prognosis, as did patients who had greater than 8000 WBC count. Of the variation in %LG, 43% was due to the differences in differential WBC counts among the patients, with the remaining variation attributed to changes in the buoyant densities of the leukocytes. These data suggest that further study of the factors effecting buoyant density of cells may be clinically useful.

Bacterial meningitis and sensorineural hearing loss: a prospective investigation.

The objectives of the present investigation are as follows: to prospectively assess the incidence of sensorineural hearing loss (SHL) associated with bacterial meningitis; to evaluate the onset and degree of SHL; and to describe the audiometric pattern. Forty-seven patients were studied otologically and audiologically. The incidence of SHL was 11%. Late onset of SHL was not observed, however, one patient demonstrated a probable progressive hearing loss. Both bilateral and unilateral hearing loss were noted. The degree of hearing loss varied from mild to profound, with no consistent audiometric pattern. Intensive follow-up on one hearing-impaired patient included temporal bone polytomograms. Obliterative labyrinthitis is detailed. Antibiotic treatment and laboratory data are evaluated. Suggestions are provided for the post-meningitic course.

Ototoxicity resulting from combined administration of cisplatin and gentamicin.

The hypothesis that cisplatin can augment the ototoxicity of gentamicin was tested. Seven groups of 11 guinea pigs each were given a single dose of cisplatin either alone or 14 days before, at the beginning, midway through, or at the end of a course of gentamicin administered daily for 14 days. Blood and perilymph gentamicin and cisplatin concentrations were determined in three of the animals from each group. Auditory damage was determined in the remaining 8 animals electrophysiologically by measuring the compound action potential and alternating-current cochlear potential. Hair cell damage was determined using the surface preparation technique. An augmented ototoxic effect occurred when the cisplatin was given early in the 14-day course of gentamicin and did not occur when it was given at the end of treatment.

Oenocyte differentiation correlated with the formation of ectodermal coating in the embryo of a cockroach.

The first signs of 'embryonic membrane' deposition could be observed at the 11th/12th stage of the embryonic development, while serosal apolysis occurs, and the first signs of oenocyte differentiation could be detected at the 15th stage. When pleuropodial cuticle deposition occurs, at the 16th stage, there is a rapid increase in the number of differentiating oenocytes. At the 19th stage there are some fully differentiated oenocytics, whereas, just before the cuticulin layer of the embryonic cuticle is laid down, another wave of oenocyte differentiation could be observed. The differentiation process of oenocytes and of vertebrate cells with a rapid cell membrane biogenesis (steroid secreting cells and hepatocytes) are compared. The correlation of oenocyte differentiation with ectodermal coating deposition, with molting hormone titer and with prothoracic gland differentiation is discussed.

The incisor absent rat: an animal model for the study of otosclerosis.

The incisor absent (ia) rat is introduced as an animal model for the study of otosclerosis. Previous animal models have failed to accurately reflect the dynamic nature of this disease. Auditory brainstem response testing suggested a conductive hearing loss in the incisor absent rat as compared to age-matched normal controls. The hearing loss, which was manifested during puberty, was progressive in nature up to 18 weeks of age. Microscopic dissection of the middle ear revealed bony abnormalities of the ossicles and oval window in the incisor absent rat. Scanning electron microscopy of the ossicles demonstrated bony lesions at the incudostapedial joint and stapes footplate. Histologic examination demonstrated thickened spongiotic bone involving the otic capsule and ossicles. The incisor absent rat model possesses an inheritable defect of the otic capsule and ossicles that results in a progressive conductive hearing loss. The genetically transmitted lesion appears histologically similar to otospongiosis. The bony pathology in the incisor absent rat is caused by defective osteoclasts and transplantation of bone marrow cells from normal rats to the incisor absent rats corrects the cellular abnormality. The incisor absent rat may represent the best animal model to date for the study of otosclerosis, its cause, and clinical treatment.

Aminoglycoside antibiotics in the treatment of otologic infections.

Aminoglycoside antibiotics can be used successfully in the treatment of otologic infections caused by gram-negative bacteria. They can be particularly valuable, sometimes in combination with a beta-lactam antibiotic such as carbenicillin, in malignant external otitis, acute middle ear infections caused by gram-negative organisms, and central nervous system complications of cholesteatomas. On the basis of susceptibility tests and of the pharmacology of these drugs, we administer appropriate therapeutic doses of one of the following antibiotics: kanamycin, gentamicin, tobramycin, or amikacin. All of these drugs may be ototoxic and nephrotoxic.

Acute vestibular paralysis in herpes zoster oticus.

A case of herpes zoster oticus is presented in which the lateral and superior semicircular canals of the labyrinth were affected unilaterally. The results of several electronystagmographic examinations are described and correlated with the patient's description of symptoms. This case study indicates that disease affecting the lateral semicircular canal is reliably detected by the conventional caloric test. However, the fact that the posterior semicircular canal remained intact could not be inferred from the results of the caloric test in this case. Also the appearance of nystagmus upon eye closure appears to have been a more sensitive index of the state of the disease process than was the caloric test.

Indirect videolaryngoscopy versus direct endoscopy for larynx and pharynx cancer staging. Toward elimination of preliminary direct laryngoscopy.

Thirty-nine patients with cancer of the larynx and pharynx (33 untreated and six previously treated patients) underwent tumor mapping by both direct laryngoscopy (DL) and indirect videolaryngoscopy (IVL). The examiner in each case was unaware of the findings of the other evaluation method. After definitive treatment had been carried out so that pathologic and operative information was also available, comparisons of the accuracies of the two methods of staging were made. In 32 cases, IVL provided information equal to or better than that provided by DL, and a tissue sample also could be obtained during IVL. On the basis of these findings, we conclude that aggressive, office-based IVL can guide initial treatment planning (partial or total laryngectomy versus irradiation) and patient counseling. A confirmatory DL can be performed without surprises at the time of definitive surgery, rather than as a separate procedure - a cost-effective modification of standard practice.

Facial nerve monitoring in otologic surgery: clinical indications and intraoperative technique.

While identification of the intratemporal portion of the facial nerve is mandatory in most otologic surgical procedures, inadvertent instrumentation, traction, or thermal injury may still result from inaccurate delineation, purposeful avoidance, or false protection of this critical structure. Improved functional preservation of the facial nerve has been achieved in acoustic neuroma surgery through the monitoring of evoked facial electromyographic activity. This technique may also be used during otologic procedures in which facial nerve manipulation is anticipated in the management of recurrent cholesteatoma, temporal bone trauma, congenital deformity, or purposeful access for cochlear implantation. Potential indications for using facial nerve monitoring in contemporary otologic surgery are detailed through illustrative case presentations, and necessary instrumentation and techniques are briefly reviewed. Intraoperative monitoring can assist the surgeon in isolating the facial nerve when chronic inflammation, traumatic injury, or anomalous development has resulted in distortion or absence of microanatomic landmarks.

Aminoglycoside cochlear ototoxicity.

The aminoglycoside antibiotics streptomycin, kanamycin, neomycin, gentamicin, tobramycin, amikacin, and netilmicin are discussed in this article on cochlear toxicity of aminoglycosides. Topics discussed include pharmacokinetics, comparative studies on toxicity, toxicity in neonates and children, histopathology, and aminoglycoside monitoring.

Clinical perspectives on ototoxic drugs.

Ototoxic drugs such as salicylates, the aminoglycoside antibiotics, loop diuretics, cisplatin, erythromycin, and vancomycin are widely used in clinical practice. The most commonly used are aspirin and the aminoglycoside antibiotics. This chapter briefly discusses the pharmacology of the commonly prescribed ototoxic drugs and the doses that may result in ototoxicity. An outline for the monitoring of ototoxic drugs is presented. The role of topical ear drops as a possible cause of ototoxicity is reviewed.

Is fine needle aspiration biopsy of salivary gland masses really necessary?

The use of fine needle aspirate biopsies (FNAB's) in the outpatient setting has progressively escalated, particularly in the area of head and neck pathology. An increasing percentage of these are for salivary gland masses. We present our experience with salivary gland FNAB's at our institution for four years, from 1988-1992. One thousand and twenty-two (1,022) FNAB's of superficial masses were performed by two pathologists. One hundred sixty-three (15.9%) were salivary gland biopsies. Of these 163 cases, 21 (12.9%) were normal tissue, 77 (47.2%) were inflammatory processes, 50 (30.7%) were benign tumors, and 15 (9.2%) were malignant tumors. None of the aspirates were unsatisfactory. Tissue correlation was possible in 47 (28.8%) cases. Two false negative cases (4.3%) were identified; these were a Warthin's tumor diagnosed as chronic sialoadenitis by FNAB; and a poorly differentiated squamous cell carcinoma diagnosed as adenocarcinoma by FNAB. There were no false positive cases. Overall sensitivity was 95.7% and specificity was 100%. Our experience indicates that FNAB of salivary glands is an effective screening procedure in evaluating salivary gland masses. The cytologic diagnosis may assist the clinician in allaying patients' anxieties, as well as in further collateral workup prior to definitive therapy.