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Biomedical subjects

E Owens

Publications and source records attributed to E Owens.

At least 37 records · Page 2Linked to original sources
PubMed1984

Regional thymidine transport and incorporation in experimental brain and subcutaneous tumors.

The regional distribution and local incorporation of [14C]thymidine into a nonextractable tissue fraction, probably DNA, was measured in normal and neoplastic tissues. We studied brain tumors induced by avian sarcoma virus and ethylnitrosourea, and transplanted RG-2 intracerebral and subcutaneous gliomas. An incorporation quotient, Q, was calculated for different tumor regions and brain from the methanol nonextractable radioactivity in the tissue and the plasma concentration-time integral of thymidine. The incorporation quotient represents the rate of clearance of thymidine from blood and its incorporation into macromolecules (probably DNA). The values of Q were compared with a labeling index measured in the same tissue regions with conventional autoradiography. The following observations were made: (1) the mean plasma half-life of thymidine was 6.5 min; (2) the regional incorporation quotient in tumors varied from values comparable to normal brain to more than 100 times higher; (3) RG-2 tumors had significantly higher Qs than the other tumor models; (4) Q in subcutaneous tumors varied most widely (greater than 500-fold range); (5) the labeling index reflected the values of Q in some tumor regions but not in others; differences between the two were most frequently related to tumor cell density and the intensity of individual tumor cell labeling. A comparison of these data with previous studies of capillary permeability and blood flow in these tumor models indicates that the incorporation of [14C]thymidine into a nonextractable tissue fraction can be limited by transcapillary transport in brain tumors and by blood flow in systemic tumors, and that thymidine disposition in these tumors is not always indicative of the rate of DNA synthesis.

Animals↗
PubMed1984

Concurrent measurements of blood flow and transcapillary transport in avian sarcoma virus-induced experimental brain tumors: implications for chemotherapy.

A blood-to-tissue transfer constant, K, and tissue blood flow, F, were measured concurrently in seven rats with a total of 19 separate brain tumors induced by intracerebral inoculation of avian sarcoma virus. Regional and local measurements of K and F were obtained using double-label quantitative autoradiography with alpha-[14C]aminoisobutyric acid and [131I]iodoantipyrine, computerized microdensitometry and image analysis. Apparent tissue extraction fractions and capillary permeability-surface area products were calculated for different tumor regions, brain adjacent to tumor and tumor-free brain. The following observations were made: five histological categories of the tumors were found; significant local and regional variations of both K and F were typical in each group, resulting in marked regional variability of permeability-surface area products but more uniform values of apparent extraction fraction; the values of F, K, permeability-surface area products and apparent extraction fraction correlated poorly with morphological features of the tumors (necrosis, cellularity, cytology, location and size); the extraction fraction of alpha-aminoisobutyric acid was usually highest in tumor centers and then decreased in a gradient from tumor periphery through adjacent brain; and regardless of classification or histological features, capillary permeability and surface area, and not tissue perfusion or blood flow, seem to determine the blood-to-tissue transport processes (delivery of bloodborne materials) in most regions of these experimental brain tumors. An operational pharmacokinetic model of drug concentration in tumor tissue is developed and the results of our analysis indicate that increases in capillary permeability such as measured in these studies would not be sufficient to deliver adequate amounts of water-soluble drugs with short plasma half-lives to tumor tissue.

Animals↗
PubMed1982

Interim assessment of candidates for cochlear implants.

The Minimal Auditory Capabilities battery was administered to patients with profound postlingual sensorineural hearing loss to obtain interim audiometric indices on the relative benefits of cochlear implants and hearing aids. One group used a cochlear implant comprising a multielectrode array and a single-channel stimulator, another group wore hearing aids, with only borderline satisfaction, and the third group wore hearing aids to good advantage. Scores for the latter group were consistently higher than the borderline group on two prosodic tests, but the borderline group scored better on closed-set spondee and vowel recognition tests. Scores were essentially the same for the two groups on the remaining tests. Tentative criteria induces were applied to members of the borderline group in terms of the hearing improvement that might be anticipated from an implant.

Adult↗
PubMed1981

Speech perception with hearing aids and cochlear implants.

A battery of tests using speech materials was developed to evaluate the auditory perception skills of five subjects with profound postlingual hearing loss. Two of the subjects wore hearing aids, and three subjects used cochlear implants. Responses of the two subjects with hearing aids were consistently superior to those of the subjects with implants, and one of the three subjects with implants consistently performed better than the other two. The subjects with implants displayed wide variations in response, indicating the necessity of evaluating each implant prosthesis as it was used by a given subject. In addition to tests of auditory speech perception, a measure of lipreading ability with amplification provided useful information.

Adult↗
PubMed1981

Progressive hearing loss in children: hearing aids and other factors.

A sample of 20 children monitored for progressive hearing loss combined with 25 progressive loss cases were obtained. The effects of hearing aid use on progressive loss were examined in the context of etiology and other factors, particularly the time relations between hearing aid application and the period of progression. Results indicate a limited role played by hearing aids in progressive hearing loss. Hearing aid use was not implicate in 30 (69%) of the progressive loss subjects, questionably implicated in nine (20%), and probably implicated in five (11%). In the identification and monitoring of progressive hearing loss, it is unwise to conclude that hearing aid use is the cause of the deterioration without considering all other plausible factors.

Adolescent↗
PubMed1980

The hearing performance inventory and hearing aid use in profound hearing loss.

Subjects with profound postlingual hearing loss completed the Hearing Performance Inventory (HPI) during the course of their hearing aid evaluations. Comparisons of responses to the HPI were made for (a) subjects who wore hearing aids versus subjects who did not, and (b) hearing aid users with losses greater than 100 dB versus users with losses between 80-100 dB. The former set of comparisons indicated consistently superior performance for the aided group, and the latter set indicated consistently superior performance for the 80-100 dB group. The HPI may be a valuable tool in hearing aid considerations.

Cues↗
PubMed1979

Hearing aid evaluation for persons with postlingual hearing levels of 90 to 100 dB.

Of 20 subjects with profound (90 to 100 dB) hearing loss who underwent a careful hearing aid evaluation, 16 were able to benefit from hearing aid use. With the recommended aids, all subjects could detect speech at levels within the normal conversational range; 75% had some understanding of spondee words; and 56% successfully accomplished tasks in phoneme identification. Two subjects succeeded on a standard speech discrimination test. Ear-level instruments, five binaural, were recommended for 13 of the 16 subjects. Microphones were front-facing in the majority of instances; none were directional. Seven aids used amplitude compression. Subjects were encouraged to relate their subjective impressions, and home trial was an important part of the evaluation. In the majority of instances, lipreading scores were markedly better with hearing aid use than without.

Adolescent↗
PubMed1979

Hearing performance inventory.

The Hearing Performance Inventory (HPI) was developed to assess hearing performance in problem areas experienced in everyday listening. It consists of six sections: (1) Understanding Speech, (2) Intensity, (3) Response to Auditory Failure, (4) Social, (5) Personal, and (6) Occupational. A self-report response style is used. Sentences were written to describe a number of listening situations covering a variety of talker characteristics and communication processes. The development, current status, and clinical implications of the HPI are presented.

Attitude to Health↗
PubMed1978

Hearing aid evaluations for persons with total postlingual hearing loss.

To answer the question whether persons with total postlingual hearing loss can benefit from hearing aid use, hearing aid evaluations were carried out for 18 subjects. Nonstandardized listening tasks were necessitated because none of the subjects could discriminate speech. Subjective considerations played an integral role in the evaluation procedure. The results of the evaluations were as follows: (1) six subjects became new hearing aid users; (2) two retained the aids they were already wearing; (3) one improved when the hearing aid was changed to the opposite ear; (4) one obtained a satisfactory replacement for an inadequate instrument; and (5) eight were unable to use an aid to advantage. Thus, it is important that all persons with total postlingual hearing loss be afforded the opportunity of a careful hearing aid evaluation.

Adult↗
PubMed1978

Two years of a program in hearing-aid-related services.

A program of hearing-aid-related services is described in which a dispenser of hearing aids visits an audiology facility on a regular basis as a supplier. Surveys to assess the program were conducted during a two-year period. Of the 128 patients who participated in the study, 89% continued wearing their hearing aids during the first year and 86% during the second year. The adjustment period of about 30 days with an accompanying orientation program was crucial. Ear mold considerations and use of the hearing aid during noisy situations constituted two major problem areas. Five aids were returned to the factory during the adjustment period, six during the first year, and 15 during the second year. Group work in hearing aid evaluation and orientation was a positive factor.

Audiology↗
PubMed1978

Consonant errors and remediation in sensorineural hearing loss.

An analysis of consonant errors for hearing-impaired subjects in a multiple-choice format revealed that about 14 consonants caused most of the difficulty in consonant recognition. For a given consonant, error probability was typically lower in the initial position of the stimulus word than in the final position. When errors were made, the substitutions were limited typically to two or three other consonants, with a greater variety occurring for consonants in the final position. Substitutions tended to be the same over a wide range of pure-tone configurations. Place errors were predominant, but manner errors also occurred. In only a few instances did specific relationships occur between particular stimulus consonants and pure-tone configurations. With knowledge of the error consonants and typical substitutions, auditory recognition of consonants can be improved by programmed instruction methods. Shaping can be accomplished by a manipulation of the response foils (choices). Since it has been shown that visual recognition of consonants can also be improved, advantage can be taken of both the visual and auditory modalities in remedial procedures. Frequency of usage in the language should be considered in the ordering of consonants for retraining purposes. Work in consonant recognition should be beneficial to the hearing-impaired patient as part of a total rehabilitation program.

Hearing Loss, Sensorineural↗
PubMed1978

Therapy of heavy drinking during pregnancy.

A survey of patients registering at the Boston City Hospital Prenatal Clinic had demonstrated that 9 percent were heavy drinkers. To reduce the health hazards to mothers and children, treatment of heavy alcohol use was integrated with prenatal care. A pediatric neurologist independently examined 322 offspring, including 42 whose mothers were heavy drinkers. Frequency of congenital anomalies, growth retardation, or functional abnormalities among these 42 was twice that of infants born to abstinent or moderate drinking mothers P less than .001). Within that group of 42, there were 15 whose mothers were able to abstain or reduce alcohol intake during the third trimester. These 15 demonstrated fewer abnormalities than those 27 whose mothers had continued heavy drinking (P less than .001). Since pregnant women can be motivated to reduce heavy drinking, treatment programs can benefit both mothers and infants.

Abnormalities, Drug-Induced↗
PubMed1977

Development of the California Consonant Test.

A 100-item, multiple-choice test for consonant identification labeled the California Consonant Test (CCT) has been developed expressly for use with hearing-impaired patients. A computer-assisted analysis was obtained for the test responses of 550 patients with sensorineural hearing loss. The test seems highly sensitive to configurations of high-tone loss, but the correlation with degree of loss, especially in the instance of flat configurations, is somewhat low (-0.40). Test-retest correlation is 0.96. A correlation of 0.35 with a W-22 list indicates that the two tests are measuring different aspects of speech reception. In addition to its usefulness in identifying consonant confusions for rehabilitation purposes, the CCT may prove helpful in ranking hearing aids. For the latter purpose, two 50-item subforms, designed for equivalence, have been under observation for possible use when time is a critical factor. Repetitions of the 100-item list offer greater stability, however.

Auditory Perception↗
PubMed1976

Intraductal "noninfiltrating" carcinoma of the breast.

We are reviewing 40 patients with noninvasive intraductal carcients; 10% developed oppostie breast cancer of the invasive variety. Twenty-one patients underwent radical mastectomy in which one patient was found to have a positive axillary node. The 19 remaining patients had total mastectomy alone. No recurrence of death attributed to intraductal carcinoma was found in 39 patients available for follow-up.

Adenofibroma↗