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Biomedical subjects

G Laurell

Publications and source records attributed to G Laurell.

At least 37 records · Page 2Linked to original sources
PubMed1995

Comparative entry of carboplatin and sucrose in endolymph in the rat cochlea.

The permeability of the perilymphatic-endolymphatic interface for carboplatin was determined after lateral cerebral ventricle infusion of radioactive carboplatin (cis-diamine[1,1-cyclobutane-1-14C-dicarboxylate]platinum) to rats. [14C]sucrose, a similar weight molecule was used for comparison of the kinetics in the inner ear fluids. 14C-radioactivity was measured in perilymph and endolymph. The rate of elimination of the tracers from perilymph was equivalent indicating no difference in transport across the blood-perilymph barrier. The transport from perilymph to endolymph was very restricted for both substances. The present study indicates that the ototoxic effect of carboplatin cannot be explained by a specific endolymphatic transport mechanism.

Animals↗
PubMed1993

Monitoring of hearing during treatment of leukaemia with special reference to the use of amikacin.

Thirty-nine patients with leukaemia were followed audiometrically during treatment with broad-spectrum antibiotics. Amikacin was given during neutropenic febrile episodes. Five patients reported a deterioration of the hearing function after termination of amikacin treatment. Significant hearing threshold loss occurred in 20 patients (51%). The hearing threshold changes were small in general, except for two patients who exhibited bilateral hearing threshold changes in the frequency range 0.5-8 kHz. Using multiple linear regression analysis 22% of the changes in hearing thresholds was estimated to be related to old age, an increased trough concentration of amikacin and an impaired pretreatment hearing state. Factors found not to influence the hearing thresholds were maximum peak concentration of amikacin, cumulative duration of therapy, pretreatment renal dysfunction and concomitant use of vancomycin. It is concluded that administration of amikacin for repeated treatment courses is associated with a low incidence of serious changes in hearing function.

Adolescent↗
PubMed1992

The relative importance of the routes and sources of wound contamination during general surgery. II. Airborne.

The influence of airborne bacteria on wound contamination during biliary surgery was studied. When bacteria grew in the bile they accounted for most of the bacteria in the wound but when the wounds were free of bile bacteria many of the bacteria came from the patient's skin. It was only in wounds with little contamination from non-airborne routes that it was possible to demonstrate an effect of airborne contamination. In such a situation it was estimated that a reduction in the airborne bacteria in the operating room of about 13-fold would reduce the wound contamination by about 50%. The contamination of patient drapes from various sources and its relationship to wound contamination was studied. It was demonstrated that in areas away from the wound, the bacterial concentration on the drape surface was significantly affected only by airborne bacteria. In the area close to the wound, airborne bacteria and bacteria from the wound significantly affected drape contamination. However, it was found that more bacteria transferred from the wound to the drape surface than vice versa. Punctured gloves, impervious gowns and the number of bacteria on the patient's skin did not significantly affect the counts on the drapes' surfaces.

Air Microbiology↗
PubMed1991

The relative importance of routes and sources of wound contamination during general surgery. I. Non-airborne.

A study was undertaken to determine the relative importance of some sources, routes of transmission, and measures to prevent bacteria entering the wound during biliary tract surgery. When bacteria were growing in the bile they accounted for the majority (greater than 99%) of the bacteria found in the wound. However, when the bile was sterile the skin bacteria at the incision site were found to make a substantial contribution to the wound flora. The difference in the total wound contamination between a patient who had practically no skin bacteria and one who had an average amount was in the region of 17-fold. No transfer of skin bacteria from the surgical team through perforated gloves or by direct contact from the surface of operating gowns was demonstrated. Ten of the patients studied had septic wounds. Five of these were infected by bacteria from the bile.

Anti-Bacterial Agents↗
PubMed1991

Degeneration of the organ of Corti following intravenous administration of cisplatin.

The development of acute morphological changes in the cochlea was studied in guinea pigs given one intravenous high-dose injection of cisplatin. In the light microscope three major stages of degeneration in the organ of Corti could be recognized: 1) an initial swelling of the Hensen's cells and protrusion of the Deiters' cells into the space of Nuel enclosing the outer hair cells, 2) a gradual degeneration of the outer hair cells together with a vacuolization in the region of the base of the inner hair cells, 3) a collapse of the Reissner's membrane and the entire organ of Corti with different degrees of damage to the inner hair cells. Sporadic bulging of the marginal cells of the stria vascularis into the endolymphatic space could be observed 4 days after injection.

Animals↗
PubMed1991

Dose-dependent inner ear changes after i.v. administration of cisplatin.

The effect on the cochlear and vestibular surface structures in the inner ear of guinea pigs receiving different doses of cisplatin was studied in three groups of animals. A semi-quantitative analysis showed that cisplatin induced outer hair cell (OHC) damage which developed over days, was dose-dependent and that repeated intraperitoneal injections of a low dose of cisplatin caused OHC changes comparable to a single intravenous injection. The range of OHC damage varied generally between the three rows of OHCs, but in the most severely damaged cochleas the changes were equally distributed between the rows in the basal turn. The inner hair cells (IHCs) and sensory cells of the vestibular end organ were unaffected up to five days after an intravenous injection of cisplatin.

Animals↗
PubMed1990

An investigation of occlusive polyester surgical clothing.

The bacterial dispersion rate of people wearing operating room clothing made from several types of polyester fabric was compared to conventional cotton clothing, total-body exhaust gowns and disposable clothing. Airborne bacteria were measured in a chamber, three ultra-clean air operating rooms and a conventionally ventilated operating room. The polyester clothing was demonstrated to be much superior to conventional cotton clothing and at least as good as the total-body exhaust gowns and disposable clothing.

Air Microbiology↗
PubMed1990

Cisplatin: effects on the stretch receptor neuron of the crayfish.

The effects of cisplatin on electrical and mechanotransducer properties of the crayfish stretch receptor neuron was studied using a microelectrode voltage clamp technique. In the stretch receptor neuron, negligible changes in membrane capacitance, leak conductance, resting membrane potential, potential-dependent currents or mechanoreceptor current were seen either on acute cisplatin treatment or after long-lasting treatment for up to 2 weeks. The inhibitory GABA-sensitive synapse on the neuron was not affected by cisplatin. The cisplatin cytotoxicity on sensory neurons such as outer hair cells of the organ of Corti cannot be explained by direct effects on ionic channels of these cells including stretch-activated channels.

Animals↗
PubMed1990

High-dose cisplatin treatment: hearing loss and plasma concentrations.

Fifty-four patients with metastatic cancer were followed audiometrically during high-dose (100-120 mg/m2) cisplatin chemotherapy. Eighty-one percent of the patients showed significant changes in air-conduction hearing thresholds after completion of therapy. Thirteen percent sustained a significant hearing handicap. An interindividual variation was found, ranging from severe hearing loss after the first course to unaffected hearing after three courses. The ototoxic effect was not increased by pre-existing hearing loss, but was slightly increased by age. The risk was determined more by the amount of the single dose than by the cumulative dose. The further ototoxic effect could not be predicted on the basis of the audiogram after the first course. Peak plasma concentration of platinum was measured in eight patients, and no ototoxic changes were noted below a concentration of 1 microgram/L.

Adult↗
PubMed1990

Changes of stapedius reflex and hearing threshold in patients receiving high-dose cisplatin treatment.

The value of stapedius reflex (SR) measurement in the clinical management of the ototoxic side-effect of cisplatin was examined in 24 patients who had received a dose of 100-120 mg/m2. The main finding was a frequent but inconsistent deterioration of the SR threshold (SRT) at 3 and/or 4 kHz, usually with a moderate rise of the hearing threshold (HT) in the frequency range 3-8 kHz. A hearing loss exceeding 60 dB HL is detected with high probability as an SRT deterioration. None of the patients showed any influence on the SRT before the HT rise could be detected. The SR test cannot replace pure-tone audiometry for the identification of cisplatin ototoxicity. The pathological SR results observed in this study indicated a cochlear lesion. It was not possible to identify those patients most susceptible to ototoxic changes from the pretreatment results of the SR test.

Adult↗
PubMed1990

Biliary tract surgery: a bacteriologic and epidemiologic study.

The sources and routes of postoperative wound infections were prospectively studied in 440 patients undergoing biliary tract surgery. The overall infection rate was 7.3%. Specimens for culture were taken peroperatively from bile, liver bed and subcutaneous fat in 402 patients and also from skin in 64. Of the 126 patients with positive bile culture (31%), all but one had bacteria in the other intraoperative cultures, with high counts of bile bacteria in liver bed and transfer of such bacteria to subcutaneous fat in 81.2%. The wound infection rate in this group was 12.8%. Of the 276 patients with sterile bile, more than 90% had bacteria in the other intraoperative cultures. The degree of contamination was low, with dominance of typical skin bacteria, and the group wound infection rate was 3.2%. In 19 postoperative wound infections intraoperative cultures were available for comparison. Eleven of these infections were classified as endogenous, six as exogenous and two as of uncertain origin. S. aureus was uncommon in bile and intraoperative wound cultures, but was almost as common as E. coli in the etiology of postoperative wound infections, indicating high pathogenicity.

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

Vibratory stimulation as a treatment alternative in patients with tinnitus.

We evaluated the effect of vibratory stimulation on 10 patients with tinnitus and controlled it in a double-blind crossover trial against the sound stimulus delivered by the same apparatus. Five patients reported decreased intensity of tinnitus during treatment when vibratory stimulation was used, as opposed to 1 patient who reported decreased intensity of tinnitus when only the sound stimulus was used. There were no significant differences between the groups in the reduction of the unpleasantness associated with tinnitus. No longterm effects of treatment were seen.

Adult↗
PubMed1988

Acupuncture for the alleviation of tinnitus.

The present study describes the effect of acupuncture in 12 patients with tinnitus. The patients were referred from the Department of Audiology, Karolinska Hospital, where their hearing and tinnitus were assessed. None of the patients had benefited from previous treatment for tinnitus. The selection of acupuncture points depended on the individual and was, to a limited extent, based on traditional Chinese medicine (TCM). Local points such as Si 19, Sj 17, and Sj 21 were fairly standard; distal points took into account associated problems of the patient, but were also points recommended in TCM for tinnitus. Ten treatments were attempted within a 6- to 12-week period. The treatments were carried out weekly or biweekly depending on the availability of patient and acupuncturist. Six patients had transient effects and noise reduction. However, no positive long-term results were obtained. Similarities between the experience of tinnitus and of pain are discussed in light of these findings.

Acupuncture Therapy↗
PubMed1988

Ototoxicity of cisplatin in gynaecological cancer patients.

The ototoxic side effect of a moderate dose of cisplatin was studied by regular audiometric investigations in 186 women with gynaecologic cancer. Cisplatin was given in a dose of 50 mg/m2 body surface by intravenous infusion every 4 weeks. High-frequency hearing loss occurred in 40 patients (22%), but in no single case was a significant change observed in the frequency range of 0.5-2 kHz. Older patients showed a statistically significant greater incidence of audiometric changes, but the pretreatment audiogram was not a predictor for ototoxic changes. It is concluded that a moderate dose of cisplatin does not effect the ability to communicate.

Adult↗
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↗