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Biomedical subjects

M Harell

Publications and source records attributed to M Harell.

At least 19 recordsLinked to original sources
PubMed1998

Middle ear pressure variations during 50% N2O anesthesia as a function of mastoid pneumatization.

HYPOTHESIS: Mastoid size is a factor in middle ear (ME) pressure regulation. BACKGROUND: In a study investigating ME pressure variations during nitrous oxide (N2O) anesthesia, particularly high values of ME pressure increase rate (PIR) were observed in four patients with sclerotic mastoids. The current study is aimed at systematically assessing this observation. METHODS: Middle ear pressure was measured periodically in 30 patients during 50% N2O anesthesia using tympanometry. For each patient, a curve representing ME pressure during anesthesia was plotted. From the curve steepness, the PIR was calculated. Extent of mastoid pneumatization was assessed planimetrically using mastoid x-rays. Ears then were divided by the median into two groups: ears with small mastoids and ears with large mastoids. The difference between the mean PIR of both ear groups was statistically analyzed. RESULTS: A significant difference between the PIR was found among the two groups. In ears with mastoids smaller than 9.475 cm2 (the median), the PIR was significantly higher than in ears with mastoids > 9.475 cm2. CONCLUSIONS: These findings support the concept that the mastoid has a ME pressure buffering capability: the larger its volume, the better its buffering capability. It is therefore suggested, that the mastoid plays a role in ME pressure regulation.

Acoustic Impedance Tests↗
PubMed1997

Dependence of middle ear gas composition on pulmonary ventilation.

The middle ear (ME) steady state gas composition resembles that of mixed venous blood. We changed arterial and venous blood gases by artificially ventilating anesthetized guinea pigs and measured simultaneous ME gas changes during spontaneous breathing, hyperventilation, and hypoventilation. During hyperventilation, PaCO2 and PvCO2 (a = arterial, v = venous) decreased from 46.0 and 53.0 mm Hg to 17.9 and 37.5 mm Hg, respectively, while PaO2 and PvO2 (85.6 and 38.2 mm Hg) did not change. This was accompanied by an ME PCO2 decrease from 70.4 to 58.8 mm Hg and a PO2 decrease from 36.8 to 25.4 mm Hg. During hypoventilation, PaCO2 and PvCO2 increased to 56.8 and 66.4 mm Hg, while PvO2 decreased to 21.8 mm Hg. The ME PCO2 increased simultaneously to 88.8 mm Hg and the ME PO2 decreased to 25.4 mm Hg. The ME PO2 decrease during hyperventilation may be explained by a 33% decrease in ME mucosa perfusion, calculated from the ME ventilation-perfusion ratio. This study shows that ME gas composition follows fluctuations of blood gas levels and thus may affect total ME pressure.

Animals↗
PubMed1996

CT of submandibular gland sialolithiasis.

We emphasise the importance of high-resolution CT with reconstruction in the demonstration of submandibular gland (SMG) sialolithiasis and its role in monitoring treatment. We studied 76 patients with swollen and tender SMG, some with fever. They underwent conventional radiography, sonography (US) and high-resolution CT with reconstructions. Conventional radiographs demonstrated single stones in 29 patients. Axial CT, before reconstructions, demonstrated single stones in 63 patients and multiple stones in another 5. Following CT reconstructions, multiple stones were demonstrated in 37 patients. On US stones were diagnosed in only 33 patients, and multiple stones in only 1. All 68 patients with stones shown on imaging and 2 without stones underwent surgery, with good clinical results. Total removal of the SMG and its duct was performed in patients with multiple stones, chronic inflammatory changes in the SMG, or a solitary stone in the SMG or deep in the duct. A small incision for removal of a solitary stone in the distal aspect of Wharton's duct was performed in 15 patients, with excellent clinical results. Another 14 patients with multiple salivary gland stones, diagnosed on CT reconstructions, did not improve following this procedure and needed further surgery; clinical improvement occurred following excision of the SMG and Wharton's duct. Histological examination in all of these confirmed the presence of additional stones. Conservative anti-inflammatory treatment was recommended for 6 patients in whom CT reconstructions did not demonstrate stones.

Adult↗
PubMed1996

Penetration of cefetamet pivoxil and cefuroxime axetil into the maxillary sinus mucosa at steady state.

The penetration of cefetamet and cefuroxime into the maxillary sinus mucosa after the administration of cefetamet pivoxil and cefuroxime axetil was investigated in patients undergoing elective surgery of the maxillary sinus. A total of 27 patients, 13 for cefetamet pivoxil and 14 for cefuroxime axetil, ranging from 15 to 70 years of age participated in this study. Each patient received three oral doses of either one tablet of cefetamet pivoxil (500 mg of GLOBOCEF) or two film tablets of cefuroxime axetil (125 and 250 mg of ZINAT) every 12 h. Sinus mucosa tissue samples were removed during surgery at times ranging from 2 to 4.5 h after the last oral administration. Blood samples were collected before drug administration, 2 h after the first and third doses, and concomitantly with tissue sample collection during surgery. All samples were analyzed by high-performance liquid chromatography. The concentrations of cefetamet and cefuroxime in plasma samples measured concomitantly with those in tissue samples ranged between 0.83 and 4.5 micrograms/ml for cefetamet and 0.59 and 3 micrograms/ml for cefuroxime. The mean tissue-to-plasma ratios calculated with reference to total (bound plus unbound) plasma drug concentrations were 0.60 (range, 0.52 to 0.77) for cefetamet (n = 4) and 0.38 (range, 0.28 to 0.44) for cefuroxime (n = 6). Both drugs seem to penetrate freely and easily into the sinus mucosa. The antibacterial activities of cefetamet pivoxil and cefuroxime axetil in cases of sinusitis therefore depend mainly on their achieved active plasma drug concentrations and their intrinsic activities in inhibiting the causative organism(s).

Adolescent↗
PubMed1996

Gas composition of the human nose and nasopharyngeal space.

Since it was established that middle ear (ME) gas composition is closer to venous gas composition than to air, the question arose regarding the composition of gas which enters the ME from the nasopharynx. Using a mass spectrometer, gaseous partial pressure was measured at three locations in the nose and nasopharynx of 6 volunteers. All three locations showed similar gas composition (O2 = 15.7%, CO2 = 4.5%, N2 + Ar = 79.8%) which is similar to expired air. The gas that enters the ME via the Eustachian tube is a mixture closer to the final ME gas equilibrium than is air. This minimizes the changes in steady state ME gas composition incurred by gas influx into the ME.

Air↗
PubMed1994

Non-explosive blast injury of the ear.

Non-explosive blast injury of the ear refers to the otological trauma caused by a blow to the ear that seals the external auditory meatus. It results in a sudden increase of air pressure within the ear canal that strikes the tympanic membrane. The present study portrays the various aspects of middle and inner ear damage in 91 patients resulting from an assault we entitled a 'non-explosive blast injury' to the ear. Sixty cases were caused by a slap or a fist, 13 patients suffered sport accidents, mostly in ball games, and 18 patients were injured during swimming and water sports activities. The common symptoms were hearing loss, earache, tinnitus, vertigo and otorrhoea. All 91 patients presented with acute perforations of their eardrums. The mean conductive hearing loss was 11.2 dB. A high tone sensorineural hearing loss was detected in only 20 per cent of the patients. A spontaneous closure of the perforation with a conservative management approach was observed in 94.8 per cent of the patients. Healing of the perforation was always associated with closure of the air-bone gap, while the results of the sensorineural hearing loss recovery were less favourable.

Adolescent↗
PubMed1990

Typing of Pseudomonas aeruginosa ear infections related to outcome of treatment.

Of 142 patients with Pseudomonas aeruginosa (PSA) ear infections, 88 (62 per cent) had chronic otitis media and 54 (38 per cent) external otitis. Following serotyping and pyocin typing of their bacteria, and relating the type to outcome, patients could be divided into three groups: (1) 120 patients who had no recurrence with isolation of only one PSA strain, (2) 13 patients who had recurrent infections and in whom the same PSA strain was isolated in repeated cultures, and (3) nine patients who had recurrent disease, but who had a change in their PSA strains. Most of the PSA strains isolated from patients in groups (1) and (2) were stable to pyocin, and resistent to gentamicin. Patients in the first group were all cured initially by medical management. Of the nine patients in group (3) who had a different serotype on repeated cultures, medical treatment was successful in eight (89 per cent), but of the 13 patients in group (2) who had the same Pseudomonas aeruginosa serotype cultured, medical therapy failed in six (46 per cent) and mastoid surgery was required. Serotyping of Pseudomonas aeruginosa otitis may be helpful in predicting the type of management in patients who have recurrent infections.

Adolescent↗
PubMed1990

Nasal transit time in normal subjects and pathologic conditions.

A radionuclide method using Tc-99m was used to measure the nasal transit time in 43 patients, including normal smokers and nonsmokers and those with various nasal or paranasal pathologies. The technique described was slightly modified from that already in use in various centers in order to enable more precise measurement. Measurement of transit time of a droplet of Tc-99m phytate on the nasal mucosa appears to differentiate patients with immotile cilia syndrome from normal controls. A positive test, however, can occur also in smokers and in patients with other nasal and paranasal problems. The test is reproducible, cost-effective, and noninvasive, enabling the clinician to make a more appropriate selection of patients needing further investigation.

Adolescent↗
PubMed1990

[Epiglottitis in adults].

Acute epiglottitis in the child is an emergency, well known to pediatricians, that requires rapid diagnosis and treatment. Aggressive treatment in recent years has markedly decreased mortality (17). Acute epiglottitis in adults has been thought to be rare, but lately numerous studies have shown an increase in the disease. We present 19 older patients, aged 13-72 (mean 44.7 years), with acute epiglottitis. A most important finding was the relatively long time from onset of symptoms until diagnosis, averaging 2.5 days. All the blood and throat cultures were negative, except for a single throat culture which yielded Pseudomonas aeruginosa. The most common presenting symptoms were severe sore-throat and dysphagia; half presented with some respiratory distress. Diagnosis was usually made on indirect laryngoscopy, but lateral X-ray of the soft tissues of the neck was found to be highly reliable. Treatment was usually conservative, including antibiotics, rehydration and steroids to alleviate edema. All patients were under strict observation for the first 48 hours, but only 1 required intubation. There were no deaths.

Acute Disease↗
PubMed1989

[Well-differentiated thyroid carcinoma].

18 cases of well-differentiated thyroid carcinoma are described, of which 5 were papillary or mixed carcinomas and 3 were follicular. In 12 of 14 in whom radio-isotope scanning was performed, a cold or indeterminate nodule was found. Fine needle aspiration was positive and concordant with the operative histological findings in half the cases examined. In 4 hemithyroidectomy was performed, and in 14 total thyroidectomy. Thyroid remnants were found on scanning in all of the 14. These remnants were ablated with radioactive iodine (131I). An ablative dose of 30 millicurie was insufficient in almost all cases and a second dose was required. 3 cases with regional spread of the tumor were reoperated, and large ablative doses of 131I(150-170 mCi) were given. In 14 cases clinical remission was achieved. Followup included ultrasonography and total body 131I scans.

Adenocarcinoma↗
PubMed1988

Acute acoustic trauma: dynamics of hearing loss following cessation of exposure.

The natural history of individuals with acute acoustic trauma who ceased to be exposed to impact noise was examined. Retrospective follow-up was carried out for 4 years on patients who were qualified as disabled following acoustic trauma with permanent threshold shift. Eight hundred forty-one individuals (1682 ears) were examined, of which 1514 ears with acoustic trauma were included in the study group; 150 individuals (300 ears) who continued to be exposed to impact noise even after discovery of acoustic trauma comprised the control group. In the latter, as long as exposure to gunfire continued, the severity of acoustic trauma increased. In the study group, during the first year after injury, changes were observed in hearing, whether improvement or deterioration; after this period, hearing loss appeared to be final. We suggest that, after 1 year following acute acoustic trauma, the associated hearing loss be considered as final, provided there is no further exposure to noise. This finding holds great importance from the medicolegal standpoint, an aspect that is unclear in the literature. It clarifies that beyond the period of 1 year after initial exposure, the pathologic process ceases (as long as there is no additional exposure to noise or gunfire). Further hearing deterioration beyond this period is not related to the initial acoustic trauma but rather to other factors.

Acute Disease↗
PubMed1987

Diffuse idiopathic skeletal hyperostosis with dysphagia (a review).

Dysphagia due to cervical osteophytes is not common. However, diffuse idiopathic skeletal hyperostosis (DISH) with cervical involvement which causes dysphagia is even rarer. The otolaryngologist is not generally familiar with this entity. The diagnosis can be made by plain cervical X-ray films, a barium swallowing esophagogram and or a CT scan of the neck. When doubt still exists, further extra-axial X-ray films can be helpful. Although most patients have been treated surgically, there may be a role for conservative therapy initially, as surgery in elderly DISH patients is often morbid and even fatal. A 79-year-old patient with DISH (Forestier's disease) is reported. Non-steroidal anti-inflammatory therapy was successfully implemented. DISH is compared with other disorders of the cervical spine which may cause dysphagia.

Aged↗
PubMed1986

Auditory brain stem responses in schizophrenic patients.

Auditory brain stem responses (ABR) were recorded from 20 schizophrenic patients, of whom ten were medicated and ten were unmedicated. A matched control group consisted of ten normal subjects. A statistically significant difference in the latencies of N3 and N5 recordings was found among the three groups. The results suggest that unmedicated schizophrenics have a delayed latency for peaks N3 and N5, and that medication (with neuroleptic drugs) shortens these delayed latencies back to the normal range.

Adult↗