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Biomedical subjects

L L Young

Publications and source records attributed to L L Young.

At least 19 recordsLinked to original sources
PubMed1995

Incidence of occult lymph node metastases in pathological stage C (pT3N0) prostate cancer.

PURPOSE: To determine the incidence of occult lymph node metastases in patients with stage pT3N0 prostate cancer. MATERIALS AND METHODS: Lymph nodes from 95 patients with stage pT3N0 prostate cancer were analyzed by immunohistochemistry for extrinsic epithelial cells using epithelial-specific monoclonal antibodies. The extrinsic epithelial cells were also tested for prostate specific antigen expression. RESULTS: Occult lymph node metastases were identified in 15 cases (16%) and were more frequent in patients with high primary Gleason grade tumors and seminal vesicle invasion (p = 0.03). In all cases the extrinsic cells were of prostate origin based on prostate specific antigen expression. CONCLUSIONS: Occult lymph node metastases can be detected in a substantial proportion of patients with stage pT3N0 prostate cancer, are associated with known predictors of disease progression, and may be useful in identifying patients at risk for recurrence and progression.

Humans↗
PubMed1994

Generation of a murine monoclonal antibody to normal mammary epithelium using mice rendered immune-tolerant to malignant mammary epithelium.

A monoclonal antibody (MAb) that distinguishes normal from malignant mammary epithelia in tissue or cell lines was generated using a procedure that involved immune-tolerization before immunization. Immune-tolerance to two transformed mammary epithelial cell lines (MCF.7 and MDA.MB.231 cell lines combined) was induced in neonatal mice within 24 hr of birth. Successful induction of immune-tolerance was determined by an indirect immunohistological method, testing sera from mice against the tolerogen (i.e., the MCF.7 and MDA.MB.231 cell lines). Mice lacking antibodies in their sera against the immune-tolerogen were subsequently immunized with an extract of normal breast epithelium. One mouse was selected for hybridoma production based on evidence of serum antibody that showed reactivity with normal mammary epithelial cells (MEC) but not with invasive breast carcinoma cells, as determined by an indirect immunohistological method. Spleen cells from the selected mouse were fused with a mouse myeloma cell line to generate MAb. After extensive screening, one MAb was further studied on the basis of reactivity with normal MEC in tissue and absence of staining of malignant MEC in tissue or tumorigenic MEC lines. This test of specificity of reactivity revealed that the antigen detected by the specific antibody was expressed on the apical plasma membrane of normal glandular epithelia that included breast, cervix, colon, lung, pancreas, and stomach, but not on their malignant counterparts in tissue sections. The antigen recognized by the MAb was termed luminal epithelial antigen with an apparent MW of 92 KD (LEA.92). This study illustrates the practical usefulness of the immune-tolerization/immunization approach in the generation of antibodies with particular specificity requirements, as in the identification of an antigen that is differentially expressed in two tissues (e.g., normal and malignant) which otherwise have a multiplicity of antigens in common.

Adult↗
PubMed1992

The judicial use of venous duplex imaging and strain gauge plethysmography (single or combined) in the diagnosis of acute and chronic deep vein thrombosis.

Sixty-eight patients (79 limbs) with clinically suspected deep vein thrombosis were evaluated by duplex imaging, strain gauge plethysmography and venography. The diagnostic accuracies were projected over a spectrum of disease incidences ranging from 10 to 90 per cent of the population. The sensitivity, specificity, positive and negative predictive values, and over-all accuracy in detecting acute deep vein thrombosis were 90.9, 87.1, 83.3, 93.1, and 88.7 per cent, respectively, for venous duplex imaging, and 81.8, 69.6, 56.3, 88.9 and 73.5 per cent, respectively, for strain gauge plethysmography. The positive predictive value and over-all accuracy of venous duplex imaging were statistically significantly higher than that of strain gauge plethysmography. When both tests were combined and compared with venous duplex imaging alone, none of these parameters were statistically significant. For chronic deep vein thrombosis, the sensitivity, specificity, positive predictive value, negative predictive value and over-all accuracy for venous duplex imaging were 75, 86, 80, 86 and 82 per cent, respectively. Fourteen per cent had inconclusive results obtained at venous duplex imaging. When strain gauge plethysmography was combined with venous duplex imaging, the over-all accuracy was 82 per cent. As the true incidence of the disease increases, the positive accuracy differences between strain gauge plethysmography and venous duplex imaging decrease to a negligible level. We concluded that over-all, venous duplex imaging is superior. However, the strain gauge plethysmography has reasonable accuracy and may be used in places where venous duplex imaging is not available. Combined use of venous duplex imaging and strain gauge plethysmography would be helpful in patients with inconclusive results obtained at venous duplex imaging and, as the true incidence increases, the positive accuracy rate of strain gauge plethysmography becomes close to that of venous duplex imaging.

Acute Disease↗
PubMed1990

Comparison of microscopic and laser diffraction methods for measuring sarcomere lengths of contracted muscle fibers of chicken pectoralis major muscle.

The objective of the present study was to compare the effectiveness of a microscopy method with a laser diffraction method for measuring sarcomere lengths of chicken pectoralis major (p. major) muscle fibers exhibiting various contraction states. Chicken p. major muscles were excised from the animals at death. Samples of each muscle were treated with pH-buffered (5.0 and 7.5) isoionic CaCl2, KCl, or ethylene glycol bis-(b-aminoethyl ether) N,N,N',N'-tetraacetic acid (EGTA) solutions in order to produce variability in the degree of fiber contraction. Sarcomere lengths (SL) of the fibers were observed using light microscopy and a laser diffraction method. The methods gave comparable results for sarcomere lengths greater than 1.6 microns. However, for SL less than 1.6 microns, sarcomere contraction was not accurately assessed by the laser diffraction method.

Animals↗
PubMed1986

Content of selected nonprotein components in poultry bone residue.

The content of selected water soluble vitamins, minerals, and cholesterol in two types of poultry bone residue was evaluated. Bone residue from skinless input materials contained slightly, although significantly, more calcium, phosphorus, and potassium than the bone residue from skin containing input materials. The former residue also contained slightly more niacin than did the latter, but the content of this and the other water soluble vitamins that were analyzed was low. The lipid material in both products contained more cholesterol than many other edible animal fats.

Animals↗
PubMed1982

Thresholds and psychometric functions of the individual spondaic words.

Two experiments were conducted concerning the relative intelligibility of spondaic words. In the first experiment, the 36 spondaic words typically used in clinical settings to determine the Speech-Recognition-Threshold (SRT) were presented to 20 subjects at levels ranging from 10 to 28 dB SPL. The percentage of persons able to repeat each word was plotted as a function of decibel sound-pressure level to determine (a) the sound-pressure level necessary to yield a 50% response point for each word, and (b) the rate at which each word became intelligible, for example, the slope of the psychometric function. By these two criteria 15 words were found to be homogeneous. In the second experiment, SRTs were obtained on 24 subjects with the full list of 36 words and with the 15 spondaic words that were homogeneous with respect to the sound-pressure level necessary for a 50% correct response level and the rate of intelligibility growth. The results demonstrate that the two groups of spondaic words yield equivalent SRTs. The data suggest that an SRT may be determined with 15 spondaic words, which is as valid and accurate as the SRT determined with the entire list of 36 words.

Humans↗
PubMed1982

Epidermal growth factor and insulin cause normal chicken heart mesenchymal cells to proliferate like their Rous sarcoma virus-infected counterparts.

Normal chicken heart mesenchymal cells at low culture density are proliferatively quiescent in a physiological culture medium containing heparinized, heat-inactivated, chicken plasma at 10%. Rous sarcoma virus-infected chicken heart mesenchymal cells, on the other hand, proliferate maximally in this same medium, undergoing a 60-fold increase in cell number during 4 days of exponential growth. When normal heart mesenchymal cells are cultured for 4 days in the presence of epidermal growth factor at 1 micrograms/ml they undergo a 16-fold increase in number, with graded responses to lower concentrations of the factor. In the presence of insulin at 10 micrograms/ml, normal heart mesenchymal cells multiply by a factor of 3 over a 4-day period. The addition of epidermal growth factor (1 microgram/ml) and insulin (10 micrograms/ml) to cultures of normal chicken heart mesenchymal cells causes these cells to proliferate at a rate comparable to that of their RSV-infected counterparts.

Animals↗
PubMed1982

Effects of acetylsalicylic acid on speech discrimination.

Speech discrimination scores were obtained in quiet and against a background of competing noise for 5 persons both before and after they had ingested large doses of acetyl-salicylic acid (aspirin). The results indicate that for some persons, aspirin produces a substantial decrease in speech understanding in noise, even though there may not be a decrease in pure-tone sensitivity or speech discrimination in quiet.

Adult↗
PubMed1981

A computer program for distinctive feature analysis.

A computer program is described that will accomplish a distinctive feature analysis for speech misarticulations. The program, which is written in FORTRAN, is interactive in nature and is straightforward in design. It greatly facilitates the use of distinctive feature analysis in articulation training, as it reduces the time necessary to complete such an analysis from several hours to approximately 15 min.

Diagnosis, Computer-Assisted↗
PubMed1981

Mitogenic factors present in serum but not in plasma.

In culture medium containing heparinized, heat-inactivated, chicken plasma, normal chicken heart mesenchymal cells do not proliferate but their Rous sarcoma virus-infected counterparts proliferate maximally. In medium containing serum derived from chicken whole blood or plasma, on the other hand, normal chicken heart mesenchymal cells proliferate actively, at similar overall rates and to similar extents. The rate and extent of normal cell proliferation are decreased by a factor of approximately 1/2 with whole blood-derived serum that is heparinized and inactivated; proliferation ceases in plasma-derived serum that is heparinized and inactivated. Heparinization and inactivation of serum does not affect the proliferation of Rous sarcoma virus-infected cells, indicating that this combined treatment eliminates a mitogenic (regulatory) rather than a supportive (nutrient) factor(s) for cell replication. We hypothesize that mitogen(s) is released from plasma protein precursors when plasma clots in the presence of formed elements of the blood or when plasma-derived serum is exposed to cultured cells; heparinization and inactivation, within the framework of this hypothesis, would render nonfunctional the plasma protein precursor(s) from which the mitogen(s) is generated. Alternatively, our data are consistent with the release of two mitogens during blood clotting, one from plasma protein precursors and the other from formed elements of the blood. We also have studied the proliferative behavior of Swiss and BALB/c 3T3 cells in whole blood-derived and plasma-derived human serum. Our studies suggest that the platelet-derived growth factor has an artifactual supportive (nutrient) role, rather than an authentic mitogenic role, in cell replication.

Animals↗
PubMed1980

The intelligibility of whitened and amplitude compressed speech in a multitalker background.

This experiment determined the effects of amplitude compression on speech intelligibility when both a target speech signal and a competing message were whitened and amplitude compressed. The target CNC discrimination words were electrically mixed with a competing message composed of five talkers. This composite signal was presented to normal hearing subjects in four ways: unmodified, whitened, whitened pplus 3:1 amplitude compression and whitened plus 10:1 amplitude compression. Discrimination functions were obtained for the CNC material by varying the signal-to-competition ratio. The unmodified and whitened speech yielded comparable discrimination functions, but reduced discrimination scores were obtained with the whitened lus compressed speech. However, the reduction in speech discrimination for the whitened plus compressed speech was slight and was most evident when the target signal and the competing background were at the same intensity.

Adult↗
PubMed1979

Failure to demonstrate antigonadotrophic activities of arginine vasotocin in the mouse.

Arginine vasotocin (AVT) has previously been proposed to be a pineal hormone which reduces reproductive competency in mammals. The effects of AVT on the growth of immature reproductive organs of the mouse have been studied using blind study techniques. Evidence is presented which fails to support the proposed role of AVT as a mammalian antigonadotrophin.

Animals↗
PubMed1976

Time-intensity trading functions for selected pure tones.

A substantial number of investigations have examined the ability of the auditory system to trade time for intensity on a lateralization task. Most of these investigations, however, have employed clicks and noise bursts as stimuli with interaural disparities between onset times. Consequently, there is a lack of quantitative data for time-intensity trades where pure tones that had identical onset times but disparate phase were employed as signals. For this reason we employed sinusoids ranging from 200 to 2000 Hz and determined the extent to which the intensity of one signal must be decreased to achieve a midline image when interaural phase disparities of 0 degrees to 360 degrees were imposed between the binaural signals in 30 degree increments. The time-intensity trading functions yielded in this experiment demonstrate that (1) not unexpectedly, the largest time-intensity trades were accomplished for the lower frequencies; (2) the maximum time-intensity trade for each frequency occurred at interaural phase disparities of 90 degrees and 270 degrees; and (3) when the low-frequency tones were 180 degrees out of phase, essentially the same intraaural intensity relationship was required to achieve midline as was needed for the 0 degree interaural phase condition.

Acoustic Stimulation↗