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Biomedical subjects

L Mendel

Publications and source records attributed to L Mendel.

At least 19 recordsLinked to original sources
PubMed2001

Symptoms, findings and treatment in patients with dehiscence of the superior semicircular canal.

Recently Minor and co-workers described patients with sound- and pressure-induced vertigo due to dehiscence of the superior semicircular canal. Identifying patients with this 'new' vestibular entity is important, not only because the symptoms are sometimes very incapacitating, but also because they can be treated. We present symptoms and findings in eight such patients, all of whom reported pressure-induced vertigo that increased during periods of upper respiratory infections. Pulse-synchronous tinnitus and gaze instability during head movements were also common complaints. All patients lateralized Weber's test to the symptomatic ear. In some of the patients the audiogram also revealed a small conductive hearing loss. However, the stapedius reflexes were always normal. A vertical/torsional eye movement related to the superior semicircular canal was seen in most of the patients in response to pressure changes and/or sound stimulation. One patient also had superior canal-related positioning nystagmus. Testing vestibular evoked myogenic potentials revealed in all patients a vestibular hypersensitivity to sounds. In the coronal high-resolution 1-mm section CT scans the dehiscence was visible on 1 to 4 sections. Moreover, the skull base was rather thin in this area and cortical bone separating the middle ear and the antrum from the middle cranial fossa was absent in many of the patients. Two of the patients have undergone plugging of the superior semicircular canal using a transmastoid approach and both patients were relieved of the pressure-induced symptoms.

Adult↗
PubMed2001

[Methods for core temperature measurements].

The measurement of core temperature is important for many clinical situations including heat illnesses, hypothermia, infections, sepsis, shock, hemorrhage, and exposure to chemical and biological agents. Currently, oral and rectal temperatures are clinically utilized for such measurements. However, oral measurements are not always possible and accurate whereas rectal measurements are not convenient in the field, are labor intensive, use fragile glassware containing mercury--an environmental contaminant, require sterilization and are not suited for mass casualties. A simple, non-invasive, non-breakable, inexpensive device to measure core temperature, which is not labor intensive, would have great use in the field and in hospitals, as well as provide an important advance in instrumentation for experimental physiology. The purpose of this work is to evaluate the different methods for core temperature measurement. Since the middle of the 18th century, the mercury thermometer has been almost the only instrument for measuring core temperature. Today, more sophisticated methods and instruments are gaining popularity. In addition, new promising converted techniques, which are about to enter the market and increase the available variety of instruments, might improve the situation as far as reliability and convenience of use are concerned. Despite the importance and usage of this variable, the progress in this field has been slower than would have been expected.

Body Temperature↗
PubMed1999

Hearing in patients operated unilaterally for otosclerosis. Self-assessment of hearing and audiometric results.

The objective of this study was to examine the outcome of unilateral stapes surgery in one patient group with bilateral hearing loss and one group with unilateral hearing loss. The patients' own estimations of improvement in hearing ability and the occurrence of other ear-related symptoms were examined retrospectively and in a follow-up study. Ninety-five of 123 patients operated for otosclerosis in only one ear between 1987 and 1992 responded to a follow-up examination. Observed audiometric findings and changes thereof, along with the patients' own estimations of their hearing handicap pre- and postoperatively, and the occurrence of other ear-related symptoms were studied. Despite good surgical results (closure of air-bone gap within 20 dB in 94%), 33% of the patients had severe hearing disabilities postoperatively, and many of these patients needed further amplification with a hearing aid. Mild dizziness occurred in 33% of the patients postoperatively and did not decrease over time. Discomfort in the operated ear due to strong sounds was reported in 20%. Change in sound quality occurred in 80% of the operated ears, but tended to disappear over time. From the results of this study it may be concluded that surgery in one ear only, leaving the other ear with poor hearing, is not an optimal hearing rehabilitation of patients with otosclerosis. It is important endevour to achieve bilateral hearing in order to give the patient good social hearing. Postoperative dizziness and unpleasant hearing quality do occur frequently, and the patients need to be informed about these problems preoperatively.

Audiometry, Pure-Tone↗
PubMed1994

Direct puncture of large arteriovenous malformations in head and neck for embolisation and subsequent reconstructive surgery.

Five patients with large arteriovenous malformations (AVM) of the head and neck, which were too large or inconveniently placed for operation alone, were treated by embolisation after direct puncture; two of them were subsequently operated upon. They all recovered without complications. Embolisation of the nidus and subsequent operation is a good alternative for the treatment of large AVM. Ligating the supplying arteries is not a treatment. If the arterial routes to the nidus have previously been closed by ligatures selective catheterisation is impossible, though direct puncture of the nidus is a possibility. The nidus of the AVM can then be obliterated by embolisation either as a treatment, or as a preoperative procedure.

Adult↗
PubMed1993

Hyaluronic acid in middle ear surgery.

The efficacy of hyaluronic acid when utilized in tympanoplasty was investigated in a multicenter, randomized, prospective patient blinded study. Of the 117 patients who completed the study, a majority (76) were treated with myringoplasty, 26 with myringoplasty combined with ossiculoplasty, and 15 with ossiculoplasty alone. The patients were evaluated by the operating surgeon up to 3 months following surgery, when the final assessment was made. The patients were divided into three groups: group 1 was treated with hyaluronic acid, 1 percent; group 2 with hyaluronic acid, 1.9 percent; and group 3 constituted the control where no hyaluronic acid was used at all. In the two test groups, utilizing hyaluronic acid, no gelatinous sponge was allowed to be left in the middle ear after surgery, whereas the control group was operated according to standard principles. The three groups were compared after the termination of the study as regards quality of healing and their hearing results. It could be concluded that the healing process within the middle ear and the tympanic membrane, as well as the hearing ability, was similar in all three groups. Thus no statistically significant differences could be obtained between the patient groups in which hyaluronic acid had been utilized in any concentration and the control group operated according to standard routine. This finding does not exclude, however, that hyaluronic acid might have a place in tympanoplastic surgery of today, since the long-term results were not evaluated here.

Adolescent↗
PubMed1991

Paragangliomas: neuroendocrine features and cytometric DNA distribution patterns. A clinico-pathological study of 22 cases.

Paragangliomas from 22 patients with extraadrenal tumours of this type were studied. Neuroendocrine features were examined using immunohistochemical techniques. Twenty-two antisera raised against neuroendocrine "markers", regulatory peptides, serotonin and intermediate filament proteins were studied in this group and cytometric DNA assessments were made by means of image cytometry. One normal and 5 hyperplastic carotid bodies were used as controls in the DNA cytometric investigations. Clinical and/or histopathological evidence of "malignancy" was present in 5 cases. The tumour cells showed heterogeneity with regard to their expression of different peptides, and the immunohistochemical analyses did not permit differentiation between benign and malignant paragangliomas. An euploid nuclear DNA distribution pattern was found in all controls and in 17 of the tumours; all except 1 were clinico-pathologically benign. An aneuploid DNA pattern was observed in 5 of the cases and some malignant features were present in 4 of these cases. DNA data may give further information apart from that obtained from the histopathological findings which may be of value in predicting the biological behaviour of this tumour type.

Adult↗
PubMed1987

Failure of critically ill patients to metabolise midazolam.

The pharmacokinetics of midazolam and its metabolite, 1-OH midazolam, were studied in six critically ill patients during and after a continuous intravenous infusion of midazolam. Four patients had an increased elimination half-life of midazolam; two were associated with a reduction in plasma clearance with low plasma concentrations of the metabolite, and two with normal metabolite levels and increased volume of distribution. The two patients with reduced clearance suffered from septic shock and were studied over a longer period. Their altered clearance was due to a reduced capability to form the 1-OH metabolite. As their condition improved, plasma concentrations of 1-OH midazolam increased and midazolam clearance returned towards normal. The impaired ability of critically ill patients with septic shock to metabolise midazolam, may be due to reduced organ perfusion and may lead to cumulation of midazolam in these patients.

Aged↗
PubMed1987

Ketamine infusion. Its use as a sedative, inotrope and bronchodilator in a critically ill patient.

A patient with acute lymphatic leukaemia developed a bilateral fulminating Pseudomonas aeruginosa pneumonia and required controlled ventilation of the lungs. Marked agitation, hypotension and bronchospasm unresponsive to conventional bronchodilators presented a therapeutic challenge. A continuous intravenous infusion of midazolam failed to provide adequate sedation. A continuous intravenous infusion of ketamine resulted in better sedation, an increase in arterial pressure and a diminution of bronchospasm. The clinical improvement was maintained for the 5 days during which ketamine was infused. Plasma concentrations of ketamine and its metabolites are reported.

Adult↗
PubMed1987

The role of prophylactic antibiotics in middle ear surgery. A study on phenoxymethylpenicillin prophylaxis.

A randomized prospective double-blind study was performed testing the value of phenoxymethylpenicillin in conjunction with middle ear surgery. The patients were evaluated for clinical signs of infection and with bacteriologic cultures both pre- and postoperatively. No difference in clinical signs of infection was noted between the pre- and postoperative evaluations. A significantly larger number of patients, however, presented with postoperative positive bacteriologic cultures as compared with the preoperative cultures. This increase was particularly evident in the placebo group. The two microorganisms that were found in increased numbers postoperatively were Staphylococcus epidermidis and Pseudomonas strains. The value of prophylactic antibiotic treatment and phenoxymethylpenicillin treatment in particular is discussed.

Adult↗
PubMed1987

The mineral content of the middle ear ossicles. A radiologic and chemical study on normal and diseased ossicles.

The underlying mechanism responsible for bone resorption in chronic otitis media with or without cholesteatoma is not sufficiently well documented. Certain areas in the middle ear are affected more often than others. The most frequent site of bony erosion in the ossicular chain is the long process of the incus. The mineral content of the ossicular chain was investigated with a clinical radiologic technique (polytomography). The findings were correlated with chemical measurements of the mineral content in normal and diseased ossicles. A poor correlation between the radiologic findings and the chemical assessment was found. The mineral content of ossicles obtained from ears with chronic otitis was similar to that of specimens obtained from healthy middle ears. The findings indicate that the demineralization process seems to be localized to a narrow zone of the ossicle and that this zone cannot be adequately visualized by standard radiologic techniques.

Absorptiometry, Photon↗
PubMed1985

A clinical comparison of the results of two different methods of closing tympanic membrane perforations.

A series of myringoplasties is presented and those cases that did not heal perfect are discussed. In order to evaluate whether some changes in the technique could further improve the results, another series incorporating these changes was operated after and the results are presented. Differences in healing and post-operative hearing between the two groups of patients are evaluated.

Adolescent↗
PubMed1980

Healing and hearing in uncomplicated myringoplasty.

In closing an uncomplicated central drum defect the technique known as an 'underlay' is widely used. This method has certain advantages and yields good results as far as both healing and hearing are concerned. In an attempt further to improve results the authors give an account of a series of myringoplasties and specifically discuss the unsuccessful cases. By a slight alteration in the operative technique used in the series presented, the authors believe that some failures can be avoided.

Adolescent↗