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Biomedical subjects

B Engström

Publications and source records attributed to B Engström.

At least 19 recordsLinked to original sources
PubMed1992

[Information to patients following surgery for cancer].

Patients who are operated upon for cancer tumour are anxious about the postoperative information and the result of the surgical procedure. This investigation was undertaken to study the routines for postoperative information in a department of surgical oncology. Thirty two patients operated for abdominal cancer ("cancer patients") and 36 patients operated for inguinal hernia or gallstone disease ("hernia patients") answered a questionnaire with 16 questions. Sixty nine percent replied. The need for postoperative information about the result of the operation was higher for the cancer patients than for the hernia patients. The cancer patients were given more attention by the doctors postoperatively and were given more opportunities to ask about the operation than the hernia patients. However, there was lack of privacy in the information situation and both groups were informed on the ward in presence of other patients.

Adult↗
PubMed1991

Orofacial functions in patients with congenital and acquired maxillary defects: a fluoroscopic study.

By means of videofluoroscopic recordings, chewing, swallowing and speech were monitored in nine patients with congenital and acquired maxillary defects. All of them were rehabilitated with a maxillary obturator prosthesis. The defective region was seldom used for chewing. No leakage between the obturator and surrounding tissue was observed, either for solids or for liquids. All of the prosthetic reconstructions were surprisingly stable during function. In the phonetic analysis, speech production was judged to be restored almost to normal. Videofluoroscopy may be valuable as a complement to other functional diagnostic procedures, and for the evaluation and improvement of rehabilitation with an obturator prosthesis.

Adult↗
PubMed1991

Clinical evaluation of restoration margins by an endoscopic microscope.

A method is presented for high magnification, clinical examination and recording of the marginal fit of dental restorations. An endoscopic microscope used in conjunction with video recording facilities affords acceptable colour records of restorative procedures for monitoring purposes. The suggestion is made that the concept of 'fit' in the clinical context has not been adequately addressed. The technique described has other clinical and research implications.

Cementation↗
PubMed1990

Stapedius reflex thresholds in relation to tails of auditory nerve fiber frequency tuning curves.

The acoustic stapedius reflex (ASR) threshold on non-anesthetized rabbits was compared to some measures of the single auditory nerve fiber activity of rabbits. The observations were made on normal-hearing animals, with some additional data from noise-exposed individuals. The results showed that the ASR threshold was reached at a sound level above saturation of discharge rate for individual neurons at their characteristic frequency (CF) in normal animals. It was found, on the other hand, that the ASR threshold measured across frequencies from 0.25 to 12.0 kHz were at a level similar to that of the tails of the frequency tuning curves (FTCs). Cochlear lesions-induced changes in FTC tail levels were paralleled by changes in ASR threshold levels. The raise of ASR threshold was, however, somewhat larger than the raise of the tails which might be explained by the significant relative decrease in the total number of units found in the frequency region corresponding to the lesion. There was also a decrease in the high spontaneous rate (SR) compared to the low and medium SR fibers for higher frequencies. It is concluded that the FTC tails can be a major eighth-nerve correlate to ASR activation.

Acoustic Stimulation↗
PubMed1990

Preservation of the human cochlea with two different fixatives.

The cochlear morphology of eight inner ears from 4 patients was studied by electron microscopy. The perilymphatic perfusion was performed in 2 of them 2 and 2 1/2 h and in 2 others, 10 and 11 h post mortem. In each patient, Karnovsky's fixative was used in one ear and Britta's fixative in the other. No structural differences between the two ears were ascertained in the patients with a short post-mortem fixation time. The cochleas with 2 h post-mortem fixation time were better preserved than those with the 10 and 11 h delay. The cochleas with the longer delay from death to perilymphatic perfusion were still fairly well preserved. However, in these cochleas the stronger fixative (Britta's fixative) gave a better preservation.

Aged↗
PubMed1990

Hearing and cochlear morphology in patients treated with a combination of cytostatics.

Patients with small-cell carcinoma of the lung were treated at the Department of Lung Medicine. They all received the same combination treatment with repeated doses of doxorubicin, vincristine, cyclophosphamide and methotrexate. In 26 patients, hearing was tested with repeated audiograms during treatment. The follow-up time varied between one and 19 months (mean, 6 months). There was no significant impairment of hearing during the follow-up period. Postmortem fixation of the temporal bones was performed in 7 patients and the cochlear morphology studied. No specific alterations in cochlear morphology which could be attributed to the cytostatics were found.

Adult↗
PubMed1989

The combined effect of cisplatin and furosemide on hearing function in guinea pigs.

The effect of the combined administration of cisplatin and furosemide on the electrophysiological hearing thresholds and endocochlear DC potential (EP) was studied in guinea pigs. A lack of interaction was found in animals given repeated intraperitoneal injections of a low dose of cisplatin with a pharmacological dose of furosemide. An ototoxic interaction occurred when a moderately high dose of cisplatin was administered intravenously at a time when the strial function was most affected by a very high dose of furosemide. The interaction was seen both as a decreased EP and a pronounced shift of auditory thresholds. It is concluded that the stria vascularis plays a role in the ototoxic mechanism of cisplatin.

Animals↗
PubMed1989

The ototoxic effect of cisplatin on guinea pigs in relation to dosage.

The effect on the electrophysiological hearing thresholds and the endocochlear DC potential (EP) was studied in four groups of guinea pigs receiving different doses of cisplatin. By multiple low-dose intraperitoneal injections a permanent hearing loss was produced without a permanent decrease of the EP. On the other hand, when cisplatin was given as a single high-dose intravenous injection, there was an impairment of the electrophysiological hearing thresholds and EP, depending upon the level of cisplatin dose. It is concluded that cisplatin-induced hearing loss is not necessarily a sequela to a loss of EP.

Animals↗
PubMed1989

Noise level, inner hair cell damage, audiometric features, and equal-energy hypothesis.

Rabbits were exposed to 2- to 7-kHz noise either for a short duration at a high sound-pressure level (15 or 30 min at 115 dB SPL), or a long duration at a low level (512 h at 85 dB SPL). The high-level exposure produced a hearing loss in the frequency range 2-6 kHz, whereas the low-level exposure gave maximum hearing loss at 12-20 kHz. The 115-dB exposure caused significantly more damage to inner hair cells than the 85-dB exposure. The implications of the present results for evaluating audiograms, equal-energy hypothesis, risk criteria, and subjective auditory features are pointed out.

Animals↗
PubMed1989

Acoustic middle ear reflexes in laboratory animals using clinical equipment: technical considerations.

Acoustic middle ear muscle reflexes (AMR) were examined in nonanesthetized rabbits using clinical oto-impedance devices to determine the feasibility of utilizing clinically available instruments in studies of laboratory animals, particularly with regard to parameters such as probe tone frequency and intensity. The Karolinska Sjukhuset clinical impedance instrument and the Madsen Electronics ZO174 standard clinical impedance meter were used. The results of this study show that reliable AMRs and tympanograms can be obtained from rabbits with both clinical instruments. Probe tone frequencies in the range of 800-1,200 Hz were most effective for eliciting tympanograms and the AMR in rabbits. The probe tone level was also found to be an important factor, with the most reliable sound pressure level being around 70 dB SPL, and below that of the reflex threshold. Both clinical instruments recorded AMR threshold elevations in animals with 7th-nerve and cochlear lesions. AMR decay was observed at 8 and 12 kHz, but no decay was seen in normal-hearing animals up to 4 kHz, suggesting that this frequency may be suitable for detecting and measuring pathological decay in the rabbit. The overall results suggest that standard oto-impedance instruments with a probe tone frequency of 1,000 Hz may be used effectively in experimental studies of several aspects of the AMR in laboratory animals, such as rabbits.

Acoustic Impedance Tests↗
PubMed1988

Eighth nerve fiber firing features in normal-hearing rabbits.

Neural activity of single eighth nerve fibers was recorded with glass microelectrodes in anesthetized normal-hearing rabbits. The units had a spontaneous rate ranging from 0 to approximately 120 spikes/s. In a large number of fibers this rate was below 2 spikes/s. The frequency tuning curves (FTCs) had a tip and a tail region for fibers with a high or medium characteristic frequency (CF). For low-frequency units the FTC was more symmetrically U-shaped. The tip threshold reached the behavioral threshold and units with thresholds of up to more than 60 dB above the mean behavioral threshold were found. There was a weak negative correlation between spontaneous rate and tip threshold. Frequency selectivity, Q10, was about 2 for units with CF below 2 kHz and about 5 for those with CF above 4 kHz. The peristimulus time (PST) histogram showed an initial peak, a plateau, and poststimulus inhibition. For the majority of fibers the dynamic range was 20-30 dB. Some fibers did not reach saturation within the stimulus intensity available. The tip-to-tail distance was 50 dB for high-frequency units at one octave below CF, a matter of potential interest for further studies of animals with inner ear lesions.

Animals↗
PubMed1987

Ototoxicity of cisplatin.

Ototoxicity is one of the unwanted side effects of cisplatin treatment. The first sign of hearing loss usually appears 3-4 days after the drug administration and occurs primarily in the higher frequencies. One hundred and eighty-six women treated with a moderate dose of cisplatin (50 mg/m2 every 4 weeks) for gynaecological cancer were studied. No significant loss of hearing was detected in the speech frequency range. Since the cisplatin concentration in the inner ear is highest after a single high dose injection, systemic audiometric monitoring is advisable during cisplatin therapy with single high dose regimen.

Animals↗