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Biomedical subjects

M Casselbrant

Publications and source records attributed to M Casselbrant.

12 recordsLinked to original sources
PubMed1994

Sensorineural hearing loss from quinolinic acid: a neurotoxin in middle ear effusions.

Quinolinic acid (QUIN) is an endogenous metabolite that exerts a neurotoxic effect by binding to specific neuronal receptors. Studies involving a broad spectrum of infectious and inflammatory central nervous system diseases have suggested a role for QUIN in causing neuronal injury. Since there is evidence for presence of the QUIN receptor in mammalian cochleas, QUIN was measured in middle ear effusions (MEEs). Gas chromatography/mass spectrometry detected QUIN in each of 65 diluted human MEEs, with a mean of 482 +/- 75 (SEM) nmol/L and a range from 15 to 2667 nmol/L. QUIN was also detected in each of 197 chinchilla MEEs from five different models of otitis media, with a mean of 10.6 +/- 1.3 (SEM) mumol/L and a range from 0.23 to 146.0 mumol/L (corrected for dilution). To determine whether QUIN causes sensorineural hearing loss (SNHL), QUIN solutions were placed on round window membranes (RWM) for 20 to 240 minutes, in 20 chinchillas. SNHL was detected by electrocochleography in QUIN-exposed animals, but not in saline controls. We conclude that QUIN is present in MEEs and that QUIN in the middle ear has the potential to cross the RWM and cause sensorineural hearing loss, possibly by binding to specific neuronal receptors in mammalian cochleas.

Animals↗
PubMed1990

Otolaryngologic manifestations of child abuse.

The number of reported cases of child abuse has increased dramatically over the past several years. Maltreatment of children can take several forms including neglect, sexual abuse, physical assault and psychological trauma. Five cases of child abuse presenting initially to the Otolaryngology Service are outlined: bilateral auricular hematomas, recurrent tympanic membrane lacerations, a pharyngeal laceration with retropharyngeal abscess and medical neglect of a patient with a parotid malignancy and one with laryngeal papillomatosis. Characteristic presentations and risk factors in family background are discussed toward the goal of early recognition and appropriate intervention.

Carcinoma↗
PubMed1989

Subacute sinusitis in children.

The bacteriologic characteristics of subacute maxillary sinusitis have not been delineated in the pediatric age group. Forty children between the ages of 2 and 12 years with respiratory symptoms for at least 30 but less than 120 days were evaluated. Nasal discharge and cough were the most prominent symptoms. Common radiographic findings were diffuse opacification and mucosal thickenings. Sinus aspiration was performed on 52 sinuses of 40 children. Bacterial colony counts greater than or equal to 10(4) colony-forming units per milliliter were found in 30 (58%) of 52 sinus aspirates obtained from 26 (65%) children. The bacterial species most commonly recovered were Streptococcus pneumoniae, Haemophilus influenzae, and Branhamella catarrhalis. Twenty-five percent of the maxillary sinus isolates were beta-lactamase producing; however, many of these were recovered from patients who had recently received antimicrobial therapy. Subacute and acute maxillary sinusitis are similar in regard to causative organism, clinical presentation, and radiographic findings.

Child↗
PubMed1984

Asthma and bacterial sinusitis in children.

Signs, symptoms, and radiographic abnormalities of sinusitis are frequent in children with asthma; it is not known whether sinus inflammation is associated with bacterial infection or other mechanisms. Eight asthmatic patients with exacerbation of asthma despite bronchodilator therapy were studied after maxillary sinusitis was confirmed by radiographs. All had cough, wheezing, nasal stuffiness, rhinorrhea and were afebrile. Four patients had headaches, and two had facial pain. Maxillary sinus aspirates were obtained, and bacterial cultures were positive in five: Branhamella catarrhalis (2), nontypeable Hemophilus influenzae (2), Streptococcus pneumoniae (1). Nose and throat cultures did not correlate with sinus cultures. All patients received bronchodilators, and four of eight patients received steroids. All were treated for 14 to 28 days with antibiotics during which seven of the eight patients improved clinically including all with positive sinus cultures. Asthma-symptoms diary scores were kept by five; all demonstrated improvement. Pulmonary-function tests improved in five of seven patients after the antibiotic and asthma therapy including the four patients with positive cultures. Sinus radiographs cleared in three, improved in three, and were unchanged in two patients after antibiotic therapy.

Anti-Bacterial Agents↗
PubMed1984

Treatment of acute maxillary sinusitis in childhood: a comparative study of amoxicillin and cefaclor.

Maxillary sinus aspiration and quantitative culture of the aspirate were performed in 50 patients, ranging in age from 1 to 16 years, with clinical and radiographic evidence of acute sinusitis. Of 79 sinuses aspirated, at least one was found to be infected in 35 (70%) children. Streptococcus pneumoniae, Branhamella catarrhalis, and Haemophilus influenzae were the most common organisms recovered. All H. influenzae were nontypeable. Twenty percent of the H. influenzae and 27% of the B. catarrhalis organisms were beta-lactamase positive and amoxicillin resistant. The subjects received either amoxicillin or cefaclor at a dose of 40 mg/kg/day in three doses for 10 days. The clinical cure rate with amoxicillin was 81%, compared to 78% with cefaclor. Radiographic improvement was similar in both treatment groups. Antibiotic therapy failed in four patients; three had been given amoxicillin, and one cefaclor. In three of these, a beta-lactamase-positive antibiotic-resistant bacterial species was recovered from the maxillary sinus aspirate; the fourth aspirate was sterile.

Acute Disease↗
PubMed1984

Hearing threshold measurement in Menière's disease.

The hearing thresholds of 21 subjects with a typical history of Menière's disease on one side were determined four times by Békésy audiometry at fixed frequencies (250, 500, 1 000 and 2 000 Hz). The reliability of the hearing thresholds was calculated and no differences could be found between the Menière ear and the unaffected ear. A considerable increase in standard deviation of hearing thresholds could be noted if the middle ear pressure varied more than +/- 50 mm H2O between the tests. The results showed that with Békésy audiometry a 7-dB increase or decrease in hearing thresholds reflects a significant change in hearing in Menière's disease.

Adult↗
PubMed1980

Current status of pressure chamber treatment.

Forty-five patients with unilateral and one patient with bilateral Meniere's disease were exposed to underpressure in a pressure chamber during an acute attack that was primary in 24 and recurrent in 23. The patients were instructed to avoid active equilibration during reduction of the pressure, in order to induce an overpressure in the middle ear. Treatment was promptly followed by improvement of hearing in 20 patients (21 ears) and by a remission for more than three years in seven cases. No side effects were observed. We therefore believe that this procedure may be useful in the prevention of damage to the cochlear hair cells with secondary permanent loss of hearing.

Atmospheric Pressure↗
PubMed1979

Hearing improvement in attacks of Meniere's disease treated with pressure chamber.

A method to reduce endolymphatic pressure by exposing patients with Meniere's disease to underpressure has earlier been described. In this work the possible mechanisms are discussed. A material of 36 patients with acute attacks, treated in this way, is now presented. 15 out of these patients experienced a rapid hearing improvement. In 11 cases the remission has lasted for more than 1 year. The method seems to be of great value for those who improved, since at least an early permanent damage to the cochlea can be avoided.

Atmosphere Exposure Chambers↗
PubMedDate not supplied

Volume displacement of the tympanic membrane in the sitting position as a function of middle ear muscle activity. A quantitative microflow method.

An open microflow meter system has been worked out for quantitative recording of the volume displacement of the tympanic membrane and its movement direction at stapedius reflex. An acoustically elicited M. stapedius contraction can be recognized by the characteristic response and latency time. The stapedius reflex contraction causes an outward or inward movement of the tympanic membrane. The magnitude of the volume displacement of the tympanic membrane is influenced by the middle ear pressure and in some ears the movement direction of the tympanic membrane changes.

Adult↗
PubMedDate not supplied

Volume displacement of the tympanic membrane at stapedius reflex activity in different postures. Studies on variations in perilymphatic pressure.

With the microflow method the volume displacement of the tympanic membrane and its direction of movement can be recorded at stapedius reflex contraction. There is an outward or inward movement of the tympanic membrane, which is affected by changes in posture. The results indicate that the perilymphatic pressure in man varies with the posture and that these variations can be measured indirectly outside the tympanic membrane. This can only be done, however, on condition that there are no pressure variations across the tympanic membrane. This method opens up new ways of studying possible pressure changes in the inner ear in acute diseases.

Auditory Threshold↗