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The main objectives of this study were (i) to evaluate the serum pharmacokinetic behaviour and milk penetration of marbofloxacin (MFX; 5 mg/kg), after intravenous (IV) and intramuscular (IM) administration in lactating goats and simulate a multidose regimen on steady-state conditions, (ii) to determine the minimum inhibitory concentration (MIC) and mutant prevention concentration (MPC) of coagulase negative staphylococci (CNS) isolated from caprine mastitis in Córdoba, Argentina and (iii) to make a PK/PD analysis by Monte Carlo simulation from steady-state pharmacokinetic parameters of MFX by IV and IM routes to evaluate the efficacy and risk of the emergence of resistance. The study was carried out with six healthy, female, adult Anglo Nubian lactating goats. Marbofloxacin was administered at 5 mg/kg bw by IV and IM route. Serum and milk concentrations of MFX were determined with HPLC/uv. From 106 regional strains of CNS isolated from caprine mastitis in herds from Córdoba, Argentina, MICs and MPCs were determined. MIC90 and MPC90 were 0.4 and 6.4 µg/ml, respectively. MIC and MPC-based PK/PD analysis by Monte Carlo simulation indicates that IV and IM administration of MFX in lactating goats may not be adequate to recommend it as an empirical therapy against CNS, because the most exigent endpoints were not reached. Moreover, this dose regimen could increase the probability of selecting mutants and resulting in emergence of resistance. Based on the results of Monte Carlo simulation, the optimal dose of MFX to achieve an adequate antimicrobial efficacy should be 10 mg/kg, but it is important take into account that fluoroquinolones are substrates of efflux pumps, and this fact may determine that assumption of linear pharmacokinetics at high doses of MFX may be incorrect.

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3 patients with Arnold-Chiari malformation with vertigo as the sole clinical presentation are described. 2 of them had been undiagnosed for many years despite repeated examinations, including CT scans. The third patient was diagnosed 2 weeks following the initial vertiginous attack. Downbeating nystagmus demonstrated by electronystagmography, indicating a pathological lesion at the craniocervical junction, was the key finding that led to the diagnoses. Following this finding, CT scan directed to the craniocervical junction showed the typical image of Arnold-Chiari malformation. The cases presented emphasize the important contribution of electronystagmography in the evaluation of vertigo due to intracranial lesions. However, computerized imaging examination remains the main diagnostic tool for intracranial pathologic processes.

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Necrotizing fasciitis is a severe soft tissue infection caused by both aerobic and anaerobic bacteria and is characterized by a rapid extension along fascial planes and by necrosis of soft tissues. The disease rarely occurs in the head and neck. Three cases of necrotizing fasciitis of the neck after a dental infection are presented. The difficulty in diagnosing the early stage of this condition in relation to other soft tissue infections of odontogenic origin in the neck is discussed. The importance of an early diagnosis followed by an appropriate combination of medical, surgical, and dental treatment is emphasized.

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The effects on auditory function caused by the implantation of 2-cyano-butyl-acrylate adhesive in the middle ear was investigated in experimental animals. Auditory brainstem responses to click stimuli were used to measure hearing thresholds prior to and following implantation of 2-cyano-butyl-acrylate adhesive in the middle ear of guinea pigs. A permanent and deep threshold shift observed at 2 months in 62% of the examined animals, suggested that this tissue adhesive is an ototoxic middle ear implant material and should not be considered in reconstructive middle ear surgery. The functional data correlate well with some of the previous morphological observations.

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The effects on auditory function caused by implantation of the bioactive glass ceramic Ceravital in the middle ear of guinea pigs was investigated. Auditory brain-stem responses (ABR) were used to measure hearing function. A threshold shift due to a conductive hearing loss was observed immediately post-operatively. This threshold shift increased towards the 20th post-operative day and improved thereafter. Surgical manipulation of the middle ear and biochemical reactions between the Ceravital granules and the middle ear wall may have contributed respectively to the immediate and late temporary ABR threshold shift recorded. However, cochlear function was not affected by middle ear implantation of Ceravital. These results correlate well with morphological studies of Ceravital implanted in the middle ear and give further support to the safe use of Ceravital as an implantation material in middle ear reconstructive surgery.

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Patients with achalasia tolerate considerable distension of the esophagus. Respiratory symptoms usually are due to regurgitation and pulmonary aspiration of retained food rather than to a space-occupying mechanism. We describe a case of previously undiagnosed achalasia presenting in an elderly woman with symptoms consistent with tracheal obstruction of acute onset.

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The anatomy of the middle ear of the blind mole rat, a subterranean rodent that uses seismic signals for long distance communication, is described qualitatively and quantitatively. The ossicular chain is of the parallel type with a lever arms ratio of 0.55 and an effective areal ratio of stapedial footplate to eardrum of 0.09. Assuming an ideal mechanical transform, the calculated fraction of acoustical energy theoretically transmitted to the cochlea, indicate low efficiency for airborne sounds. This is in accordance with the relatively high electrophysiological and behavioral threshold, shown previously. We suggest that a unique morphology of the middle ear and of the articulation between the lower jaw and the skull, as well as a peculiar 'jaw listening behavior' enable seismic vibrations to be transmitted to the inner ear mainly by bone conduction, thereby compensating for the limitation in receiving airborne signals.

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In elderly subjects suffering from presbycusis a clinical picture of sudden hearing loss, tinnitus and vertigo may be precipitated by a superimposed serous otitis media. Such an abrupt and dramatic sensory deficiency may be erroneously ascribed to an acute cochlear lesion and given grave prognostication. This situation was observed in 12 patients during a period of 2 years. Appropriate diagnostic evaluation revealed the true nature of the disease and simple therapeutic measures promptly restored the auditory function to its previous level.

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Auditory brainstem evoked potentials (ABP) were recorded in 59 healthy neonates and infants whose age ranged from 3 days to 18 months (6 age groups). Latencies of individual waves and the interpeak latencies (IPL) of I-III, III-V and I-V were analysed. A different maturational pattern was observed in the pontomedullary and the pontomesencephalic segments of the brainstem. Latencies of all waves except wave I were longer in male than in female babies. Establishment of normative data related to the technical variables employed by the individual team is a sine qua non prerequisite for adequate neurological evaluation of ABP.

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Auditory brain stem potentials (ABP) were recorded in 27 patients with Bell's palsy during the early phase of the disease and 1-3 months later. Pathological findings were observed in 6 patients, the dominant features being prolonged brain stem transmission time and diminished amplitude of the second wave. The extension of the pathological process in the so called idiopathic peripheral facial paralysis appears to vary. The observation of brain stem involvement in some patients with Bell's palsy may have important clinical implications.

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Bleeding in the salivary glands represents a very rare complication of oral anticoagulant therapy. Only one such case has been previously described in the submandibular glands. To the best of our knowledge, we document the first case of hemorrhage in the parotid gland following the ingestion of coumarin compounds.

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A case of familial pemphigus vulgaris is described in an uncle and his niece who developed the disease 18 years apart. The man died from pemphigus in 1964. The diagnosis was confirmed histopathologically in both cases, but immunofluorescent microscopic studies were performed only in the woman because the technique was not available in 1964. HLA typing in the woman and her daughter and sister showed A 26, BW 38 and DRW 4 in all of them. Clinical disease did not develop in the other family members.

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The introduction of a small quantity of air by lumbar puncture in the lateral decubitus position followed by high-resolution computerized tomography (CT) scanning is a simple method allowing optimal visualization of the cerebellopontine angle cistern and the internal auditory meatus. Our experience with 37 CT pneumomeatographies in 22 patients who had clinical and audiometric findings suggestive of retrocochlear lesions is presented. Thirty-two examinations were normal, and 5 revealed small acoustic neuromas. In all cases, conventional X-rays, multidirectional tomography and contrast CT were nonconclusive. We advocate that CT pneumomeatography be the procedure of choice in the diagnosis of purely intracanalicular or very small extracanalicular acoustic neuromas.

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Caudal vs rostral transmission time has been studied in patients with multiple sclerosis (MS). In the majority of the cases, prolongation in latency was more severe in the caudal segment, which suggests that this part of the brainstem is more commonly affected in MS. The difference between pontomedullary and pontomesencephalic transmission time yields a variable that may prove a valuable adjunct in the electrodiagnosis of MS.

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A characteristic pattern of ABR was observed in hyper-and hypofunction of the thyroid gland. The most conspicuous change took place in the BSCT. Its value correlated well with the level of serum T4. Dynamic changes of ABR pattern were recorded during the development of myxedema and on return to an euthyroid state. This preliminary study suggests that examinations of ABR may serve as a tool in the overall assessment of thyroid status.

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Hearing function and auditory brainstem potentials were evaluated in nine members of three generations of a family affected with Friedreich's ataxia. The characteristic findings were high-frequency sensorineural hearing impairment of varying severity and diminished or absent N1, N2, and N3 responses. These electrophysiologic aberrations correlate topographically with previously reported pathological observations.

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The characteristic features of auditory brain stem responses (ABSR) are described in seven cases of cerebellopontine angle tumors: five acoustic neuromas, one congenital cholesteatoma, and one meningioma. An attempt is made to correlate the N1 response with the degree of auditory nerve involvement, to gain information about the presence of brain stem displacement, and to evaluate the cranial extension of the lesion by recording responses to contralateral stimuli. The empirical nature of deductions based on crossed stimulation is emphasized. In tumors originating from the VIIIth nerve, the ABSR pattern is characterized by a well-defined N1 complex, indistinct or absent additional responses, and prolonged brain stem conduction time (BSCT) on the affected side whenever its assessment is feasible. Recording from the affected side on stimulation of the contralateral side may show normal responses from stations central to the auditory nerve in cases of small-sized tumors. Medium or large tumors may be accompanied by abnormal N2 and/or N3 responses suggesting involvement of these stations.

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