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Biomedical subjects

R E Brummett

Publications and source records attributed to R E Brummett.

At least 37 records · Page 2Linked to original sources
PubMed1987

Wound healing and the Shaw scalpel.

The Shaw heated scalpel is now widely used in head and neck surgery because it provides better hemostasis intraoperatively. Concerns persist over the immediate and long-term effects of this instrument on wound healing. This study compares heated and unheated Shaw scalpel incisions in the skin of 7-week-old piglets. Tensile strength measurements and histologic evaluations were made at frequent intervals up to nine weeks after incision. Histologic studies showed no differences in the two groups at any time in the study. Tensile strength of wounds was significantly less two weeks after incision in the Shaw scalpel group, but following that time, the wounds increased in strength, and by seven weeks, the two groups were equal in this respect. Thus, we conclude that the Shaw scalpel wounds in pigs are, ultimately, similar to standard scalpel wounds, although there is a period of diminished tensile strength.

Animals↗
PubMed1987

Effects of pentoxifylline on experimental skin flap survival.

We studied the effects of pentoxifylline on experimental skin flap survival in the domestic pig. Random skin flaps were designed using a length-width ratio of 5:1. The pigs were then given pentoxifylline (25 mg/kg/d) or placebo for seven days. Fluorescein sodium was used to help determine surviving skin flap length seven days postoperatively. Results showed no significant difference in mean surviving skin flap length between the study and control groups. We question the value of pentoxifylline in increasing skin flap survival.

Animals↗
PubMed1987

Absence of ototoxicity of teichomycin A2 in guinea pigs.

Teichomycin A2 is a new antibiotic that is similar to vancomycin. Because vancomycin is reported to be ototoxic, teichomycin A2 was tested for ototoxicity. No evidence of ototoxicity was found. Furthermore, ethacrynic acid, a diuretic that augments the ototoxicity of many drugs, did not enhance ototoxicity with teichomycin A2.

Animals↗
PubMed1986

Relative efficacy and toxicity of netilmicin and tobramycin in oncology patients.

We prospectively compared the efficacy and safety of netilmicin sulfate or tobramycin sulfate in conjunction with piperacillin sodium in 118 immunocompromised patients with presumed severe infections. The two treatment regimens were equally efficacious. Nephrotoxicity occurred in a similar proportion in patients treated with netilmicin and tobramycin (17% vs 11%). Ototoxicity occurred in four (9.5%) of 42 netilmicin and piperacillin and in 12 (22%) of 54 tobramycin and piperacillin-treated patients. Of those evaluated with posttherapy audiograms, three of four netilmicin and piperacillin-treated patients had auditory thresholds return to baseline compared with one of nine tobramycin and piperacillin-treated patients. The number of greater than or equal to 15-dB increases in auditory threshold as a proportion of total greater than or equal to 15-dB changes (increases and decreases) was significantly lower in netilmicin and piperacillin- vs tobramycin and piperacillin-treated patients (18 of 78 vs 67 of 115). We conclude that aminoglycoside-associated ototoxicity was less severe and more often reversible with netilmicin than with tobramycin.

Adult↗
PubMed1985

Ototoxicity of intraventricularly administered gentamicin in adult rabbits.

To determine whether daily intraventricular injection of gentamicin sulfate is ototoxic, adult male rabbits were given 0.2 ml of saline (group 1; n = 8) or 0.25 mg/kg of gentamicin sulfate in 0.2 ml of saline (group 2; n = 7) by intraventricular infusion once a day for 21 d. All rabbits were also given intramuscular gentamicin sulfate, 2 mg/kg, twice daily. Before and after antibiotic treatment, brainstem auditory evoked responses (BAERs) were recorded. During the experimental period, neurologic examinations were performed on all rabbits. After treatment, the animals were euthanized; brain tissue and cochleas were then removed for histopathologic examination. The ratios of neurologic abnormalities observed in group 1 and 2 animals, respectively, were 0/8 and 5/7; of abnormal BAERs, 0/8 and 5/7; of abnormal brain morphology, 2/5 and 6/6; and of abnormal cochlear morphology, 0/6 and 7/7. The electrophysiologic evidence of auditory deficit and the structural evidence of ototoxic insult are significantly associated (p less than or equal to 0.006) with intraventricularly administered gentamicin sulfate. These data suggest that intraventricular gentamicin should be used with caution.

Animals↗
PubMed1984

Gillies' corner stitch revisited.

Gillies' corner stitch (GCS) has been generally accepted for closure of skin flap tips because it is commonly believed that this stitch provides the best chance for survival of a flap tip that may have a compromised blood supply. There are no experimental data, however, to support such an assumption. To test the hypothesis that other stitches might be equally efficacious, we evaluated flap tip survival after closure with two different suture techniques, the GCS and a vertical loop stitch ( VLS ). Factors used to evaluate flap tip viability were the measurement of RBC movement in the flap tip by laser Doppler technique and measurement of the length of flap tip necrosis. In our model, the GCS is not superior to the VLS in terms of flap tip survival.

Animals↗
PubMed1984

Dissociation of maximum concentration of kanamycin in plasma and perilymph from ototoxic effect.

Kanamycin was administered in total daily doses of 0 (vehicle), 100, 200 or 300 mg/kg to different groups of guinea pigs for two weeks. These total daily doses were administered according to three different dosing schedules, either as a single injection given once a day, divided into two equal doses and given twice a day, or divided into four equal doses and administered four times a day. It was found that the magnitude of the ototoxicity resulting from kanamycin administration was related to the total daily dose alone and not the dosing schedule. This lack of relationship between the dosing schedule and the magnitude of the ototoxicity due to kanamycin is the reverse of that reported for the nephrotoxicity resulting from gentamicin, tobramycin and netilmicin.

Animals↗
PubMed1982

Lidocaine in the treatment of tinnitus aurium. A double-blind study.

Available reports suggest that lidocaine is capable of relieving symptoms of tinnitus, but no convincing data support this conclusion. By use of a placebo-controlled double-blind crossover study we found that 19 out of 26 patients with subjective tinnitus reported that their tinnitus was temporarily better or gone with intravenous (IV) lidocaine and that there was no change with IV saline.

Clinical Trials as Topic↗
PubMed1982

The ototoxic interaction of viomycin, capreomycin and polymyxin B with ethacrynic acid.

The ototoxic interaction between the aminoglycoside antibiotics (streptomycin, kanamycin, etc.) and the loop-inhibiting diuretics (ethacrynic acid, furosemide and bumetanide) has been well documented. This interaction causes extensive destruction of the hair cells of the cochlea. Brummett et al. (1974) demonstrated that this interaction did not occur with the non-loop-inhibiting diuretics and kanamycin. The present study was undertaken to determine if antibiotics other than the aminoglycosides could produce the ototoxic interaction when combined with a loop-inhibiting diuretic. Three antibiotics-viomycin, capreomycin, and polymyxin B- when given with ethacrynic acid were found to produce cochlear hair cell damage that was similar to that produced by aminoglycoside antibiotics administered with ethacrynic acid. Therefore, the interaction appears to be specific to the loop-inhibiting diuretics but not specific for the aminoglycoside antibiotics.

Aminoglycosides↗
PubMed1980

A comparative study of the ototoxicity of gentamicin and gentamicin C1.

Dose-response experiments comparing the ototoxic liability of the aminoglycoside antibiotics gentamicin sulfate and gentamicin C1 sulfate were conducted on guinea pigs. Measures of cochlear electrophysiology, histology, and the pharmacokinetic disposition of the drugs in the plasma and perilymph were made. Electrophysiological and histological measures indicated that gentamicin is more ototoxic than is gentamicin C1.

Animals↗
PubMed1980

Combined effects of noise and kanamycin. Cochlear pathology and pharmacology.

Concurrent administration of aminoglycoside antibiotics and acoustic exposure is reported to result in a cochlear damage level exceeding that predicted from the effects of either agent given alone. To investigate this interaction, guinea pigs were given daily subcutaneous injections of kanamycin sulfate at 200, 300, or 400 mg/kg followed by a ten-hour noise exposure (115 or 45 dB) for seven consecutive days. Drug levels in plasma and perilymph were measured during the 24 hours after injection and during the seven-day period of drug and noise exposures. Electrophysiological and morphological evaluation of cochlear function confirmed a dramatic interaction at the 300-mg/kg dosage. Augmentation of damage was minimal at 200 mg/kg and masked by ceiling effects at 400 mg/kg. No alteration in accumulation or elimination of kanamycin occurred as a result of high-intensity acoustic exposure.

Animals↗
PubMed1979

Quantitative relationships of the ototoxic interaction of kanamycin and ethacrynic acid.

We determined the range of doses of kanamycin sulfate and ethacrynic acid that results in an ototoxic interaction in guinea pigs. In addition, we determined the time interval between the administration of the two drugs that is needed to produce this interaction. In all cases, the magnitude of the ototoxic lesion was determined by measuring the cochlea's ability to generate both the sensitivity and intensity functions of the ac cochlear potential. In addition, the cochlear pathologic conditions, as determined by counting the number of missing hair cells in the organ of Corti, was found to correlate highly with the ac cochlear potential data. The dosage range of ethacrynic acid during which the interaction occurs is very narrow, while the dose range of kanamycin is very large.

Animals↗
PubMed1979

A system for evaluating auditory function from 8000--20 000 Hz.

A system for the measurement of auditory function from 8000--20 000 Hz is described. This system introduces advances in: (a) maximum power output, (b) signal fidelity, and (c) transducer characteristics. Two case studies are presented to illustrate the clinical information gained from the measurement of high-frequency auditory sensitivity, which is not readily apparent in conventional threshold assessment.

Adolescent↗
PubMed1979

Ototoxic effects of the interaction between kanamycin and ethacrynic acid. Cochlear ultrastructure correlated with cochlear potentials and kanamycin levels.

The effects of the interaction between kanamycin (KAN) and ethacrynic acid (EA) on the ultrastructure of the guinea pig cochlea were studied 3, 4, 6, and 24 hours following administration of EA (40 mg/kg) to animals pretreated 2 h earlier with KAN (400 mg/kg). Appropriate saline (SAL) controls were included giving 4 treatments: KAN/EA, KAN/SAL, SAL/EA and SAL/SAL. The outer hair cells of the organ of Corti showed nuclear and plasma membrane changes at 3 h and were completely destroyed at 24 h. The inner hair cells were unaffected. Severe swelling was seen in the stria vascularis of both KAN/EA and SAL/EA animals at 3 h and was gone by 24 h. KAN/EA had a greater effect on the stria than had SAL/EA. These results were consistent with the time course of the effect of the drugs on the a.c. and d.c. endocochlear potentials. KAN concentrations in perilymph were unaffected by treatment with EA.

Animals↗