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Biomedical subjects

I M Young

Publications and source records attributed to I M Young.

At least 55 records · Page 3Linked to original sources
PubMed1983

Some parameters affecting Békésy audiometric thresholds.

Bekesy automatic audiometric findings may be affected by various factors such as contralateral masking, starting frequency, starting level, exposure to stimulating sound and different stages of some disease entity. These findings are seen mostly on steady-tone tracings as revealed by peak-to-peak amplitude reductions and threshold drifts. This paper is concerned with automatic audiometry parameters which have been little known or ignored by many investigators. Detailed audiometric case histories from 6 patients with a variety of unilateral sensorineural hearing impairments showed, e.g., that contralateral masking in the normal ear can produce striking effects on tracings to steady-state tones in the affected ear. Various starting frequencies produced marked effects on separation between pulsed-and steady-tone tracings if hearing was tested starting at suprathreshold levels. A patient diagnosed as having an early endolymphatic hydrops retested within 1 hr following an episodic attack displayed varieties of findings. The automatic audiometric method demonstrates the interrelation of level and adaptation.

Adult↗
PubMed1982

Loudness recruitment in abrupt drop sensorineural hearing impairment.

Monaural bifrequency loudness balance tests were performed on 11 adults with abrupt drop sensorineural hearing impairment. To study frequencies on the slope, 2-octave Bekesy threshold measurements were made beginning at a frequency exhibiting normal hearing nearest to initiation of the slope (F1). Loudness was matched (Test 1) between F1 and F2 (a frequency nearest to termination of the slope), (Test 2) between F1 and F1 + F2/2 (a frequency halfway between F1 and F2), and (Test 3) between F1 and 2F1 (a frequency an octave above F1). Our data indicated that a combination of asymptotic and straight-line recruitment was demonstrated in Test 1, pure asymptotic recruitment in Test 2, and straight-line recruitment in Test 3. It was speculated that diffuse hair cell lesions such as in frequency areas in the vicinity of 2F1 in abrupt drop sensorineural hearing impairment or endolymphatic hydrops may show straight-line recruitment, and discrete outer hair cell lesions such as frequency regions around F1 + F2/2 may demonstrate pure asymptotic recruitment. Our results were discussed in relation to histopathological findings of human and animal subjects with abrupt drop hearing loss reported by other investigators. Data appeared to show a relationship between the types of loudness recruitment and the hair cell damage.

Adult↗
PubMed1981

Evaluation of single and double artificial insemination regimes as methods of shortening calving intervals in dairy cows treated with dinoprost.

Conception rates in 535 commercial lactating Friesian dairy cows on two farms were compared between treated animals after two injections of dinoprost at an 11-day interval, and untreated contemporary controls bred by conventional artificial insemination. The conception rate for a single insemination 75 to 80 hours after the second dinoprost injection was 46 per cent, for two inseminations 72 and 96 hours after the second injection was 47 per cent, and for untreated controls was 50 per cent. The differences are not statistically significant. Both dinoprost treated groups had a mean calving interval of 366 days compared with 378 for controls. The time advantage of 12 days in calving interval was principally due to the shorter calving-to-first-service interval of treated cows. This 10-day advantage in calving-to-first-service was increased to a 12-day advantage in calving-to-conception in treated cows, and applied also to cows which failed to conceive to the induced oestrus. The accuracy of pregnancy diagnosis was confirmed by calving data; pregnancy diagnosis by rectal palpation was 94 per cent and by milk progesterone assay 81 per cent accurate, overall. Oestrus occurred in 3.8 per cent of pregnant cows, on the basis of stockmen's observations. The relevance of the information to herd sterility control is discussed.

Animals↗
PubMed1979

Fertility of norgestomet treated suckler cows.

Four studies are described involving 3050 single suckled mainly Hereford-Friesian cross beef cows treated with norgestomet and oestradiol valerate to control the ovarian cycle. In study 1 the effect of insemination timing on pregnancy rate was studied. A greater proportion of cows inseminated 48 and 72 hours after treatment became pregnant than after a single insemination at 48 hours. In study 2 large variations in fertility among farms were recorded in field trials of norgestomet and oestradiol valerate. In study 3 the effect on fertility of nutrition, weight and body condition was examined. In study 4 57.9 per cent of 1113 treated cows became pregnant to insemination at 48 and 72 hours. Cows were fed a balanced ration designed to provide for a predicted daily milk yield of 9.0 kg for a 12-week period starting six weeks before insemination. The range of fertility was from 36.7 per cent to 94.9 per cent.

Animal Feed↗
PubMed1977

Fertility of norgestomet treated dairy heifers.

Four studies are described involving 2573 Friesian heifers treated with norgestomet and oestradiol valerate to control the ovarian cycle. All treated animals were inseminated at fixed times following treatment. In study 1 insemination 48 and/or 60 hours after treatment resulted in a non-significant greater proportion of heifers becoming pregnant than at 48 X 72 hours. Large variations in fertility among farms were recorded in field trials of norgestomet (Searle) and oestradiol valerate. In study III the effect on fertility of nutrition, weight and body condition was studied. In section IV a pregnancy rate to fixed time insemination of 66-8 per cent of 500 heifers inseminated at 48 and 60 or at 48 and 72 hours after norgestomet/oestradiol valerate treatment was obtained. Heifers in study IV were fed a balanced ration designed to provide a predicted daily liveweight gain of 0-7 kg for a 12-week period starting six weeks prior to the date of insemination. The range of fertility was from 59-0 per cent to 85-7 per cent.

Animals↗
PubMed1975

Radiation dose to the eyes of the patient during neuroradiological investigations.

Radiation dose measurements suggest that patients undergoing extensive neuroradiological investigations may receive a corneal dose in excess of 60 rads in tissue over a relatively short period. - There is no direct evidence that lens damage occurs in man at this level but it is important that high dose levels should be appreciated and measures taken to reduce them. Protective spectacles have been devised to effect such a reduction in two high dose procedures, namely petrous tomography and cerebral angiography, without degradation of the radiographic image.

Adolescent↗