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Biomedical subjects

J Posner

Publications and source records attributed to J Posner.

84 records · Page 5Linked to original sources
PubMed1977

Relationships between comfortable loudness levels for speech and speech discrimination in sensorineural hearing loss.

The primary purpose of this study was to investigate the relationship between the sensation level selected as most comfortable for loudness and intelligibility, and the sensation level at which maximum speech discrimination is obtained. An articulation function was generated at five sensation levels for 45 subjects with sensorineural hearing loss. Speech discrimination scores were also obtained at sensation levels corresponding to most comfortable loudness levels for loudness and intelligibility. Results indicated that most comfortable loudness, at least under the conditions of the present study, does not appear to be the level at which maximum speech discrimination is obtained. Therefore, the use of comfortable loudness as a single sensation level for testing a subject's maximum discrimination is not recommended at this time.

Acoustic Stimulation↗
PubMed1973

Prostaglandin E2 and the bovine sphincter pupillae.

1. The bovine isolated sphincter pupillae incubated in Krebs solution releases a biologically active substance tentatively identified as prostaglandin E(2).2. The prostaglandin did not appear to be of neural origin or to result merely from tissue degeneration.3. The spontaneous release of prostaglandin E(2)-like material was related to the tone of the sphincter. Output increased as tone was acquired after setting up the tissue and fell when various procedures were used to reduce the tone.4. Low concentrations of E and F-type prostaglandins produced slow, well-sustained contractions of the atonic sphincter, prostaglandin E(2) being the most potent of those tested. The responses to prostaglandin E(2) were antagonized selectively by a prostaglandin antagonist SC-19220 (a dibenzoxazepine derivative) which in higher concentrations caused dose-dependent relaxations of the preparation.5. Prostaglandins did not appear to modulate transmission from nerve to muscle in the sphincter.6. The hypothesis that prostaglandin E(2) might be produced to act as a local hormone causing tonic contraction of the sphincter pupillae is discussed.

Acetylcholine↗
PubMed1971

Studies on prostaglandin antagonists.

1. Three prostaglandin antagonists have been examined for their ability to block PGE(2) and PGF(2alpha) on human, guinea-pig and isolated rat gastrointestinal muscle.2. 7-oxa-13-Prostynoic acid was either a non-selective antagonist, or was ineffective on the tissues studied; it had marked spasmogenic activity on the rat fundus.3. 1-Acetyl-2-(8-chloro-10,11-dihydrodibenz (b,f)(1,4) oxazepine-10-carbonyl) hydrazine selectively antagonized the excitatory effects of PGE(2) and PGF(2alpha) in guinea-pig and rat tissues, but not in human muscle.4. Polyphloretin phosphate selectively antagonized the excitatory effects of prostaglandins in both human and guinea-pig muscle preparations, but it caused stimulation of the rat fundus.5. All the antagonists lowered the tone in many tissues. They also reduced contractions caused by potassium.6. None of the compounds blocked the inhibitory effect of PGE(2) on intestinal circular muscle.7. The implication of these results on the nature of prostaglandin receptors, and the value of each compound as a prostaglandin antagonist are discussed.

Acetates↗
PubMedDate not supplied

The effect of a submaximal exercise orientation on cardiopulmonary cycle ergometer stress test results in older adults.

BACKGROUND: Orientation sessions are sometimes used to habituate subjects before exercise stress testing. The extent of habituation in older subjects has not been clearly defined. Additionally, the use of repetitive maximal stress testing as an orientation method may not be necessarily applicable in the aged. METHODS: To determine if the employment of a submaximal orientation session would effect cardiopulmonary cycle ergometer exercise results, 266 older adults (68.6 +/- 5.0 years) male (n = 100) and female (n = 166) subjects participated in this study. One hundred thirty-one subjects received an orientation before stress testing. One hundred thirty-five did not. RESULTS: Analysis of resting values revealed no significant differences. Separate gender analysis was performed at submaximal workloads. Men were examined at 0, 60, and 105 Watts; women at 0, 45, and 75 Watts. Oriented subjects displayed significantly lower heart rates for both males and females at all submaximal workloads. Oxygen uptake was significantly lower for oriented women at 45 Watts (P < or = .05) and men at 60 Watts (P < or = .05). Oriented males displayed significantly lower systolic blood pressure at 0 Watts (P < or = .05), 60 Watts (P < or = .01), and 105 Watts (P < or = .05). The oriented group reached ventilatory threshold (VeT) at a higher workload (P < or = .001), lower heart rate (P < or = .001), and higher VO2 uptake (P < or = .05). Nonoriented subjects obtained a significantly higher maximal heart rate than oriented subjects (147 +/- 15.7 beats per minute (bpm) vs. 140 +/- 17.1 bpm, P < or = .01). Separate gender analysis revealed a significant difference (P < or = .01) in maximal heart rate in males (oriented = 137.4 +/- 18.8 bpm vs. nonoriented = 147.7 +/- 15.7 bpm). Although nonoriented women achieved a higher maximal heart rate, the difference was not significant (146.9 +/- 15.8 bpm vs. 142.6 +/- 16.0 bpm). CONCLUSION: These results indicate that both male and female older subjects display significant modification in physiologic performance from habituation after a single submaximal exercise orientation session. This effect was greater at submaximal than maximal workloads, and appears to be greater than that previously reported in younger subjects.

Aged↗
PubMedDate not supplied

Amino acid levels in elderly nursing home residents.

We have compared levels of albumin and serum amino acids in a group of 87 recent admissions to a nursing home, average age 83 years, with a group of healthy moderately old subjects, average age 69 years. We found that the nursing home group was characterized by decreased levels of albumin, by increased total levels of the measured amino acids, and by increased levels of the nonessential amino acids. In contrast, there were no significant group differences in the essential amino acids. Among the nursing home patients, there was a negative correlation between essential amino acids and disability, consistent with nutritional deficits in the more disabled patients, and a positive correlation between essential amino acids and subjective complaints of pain, suggesting that pain is associated with breakdown or mobilization of endogenous protein stores. Though the nursing home patients had decreased serum levels of tryptophan, there was no association between serum tryptophan or other variables that could be related to the availability of tryptophan for transport into brain, with ratings of either depression or pain. Glutamine levels were significantly increased in the nursing home residents, and among these patients they were positively correlated with measures of cognitive impairment.

Activities of Daily Living↗
PubMedDate not supplied

Impact of preferential flow at varying irrigation rates by quantifying mass fluxes.

Solute concentration and soluble dye studies inferring that preferential flow accelerates field-scale contaminant transport are common but flux measurements quantifying its impact are essentially nonexistent. A tile-drain facility was used to determine the influence of matrix and preferential flow processes on the flux of mobile tracers subjected to different irrigation regimes (4.4 and 0.89 mm h(-1)) in a silt loam soil. After tile outflow reached steady state either bromide (Br; 280 kg ha(-1)) or pentafluorobenzoic acid (PFBA; 121 kg ha(-1)) was applied through the irrigation system inside a shed (3.5 x 24 m). Bromide fluxes were monitored at an irrigation rate of 4.4 mm h(-1) while PFBA fluxes were monitored at an irrigation rate of 0.89 mm h(-1). At 4.4 mm h(-1) nearly one-third of the surface-applied Br was recovered in the tile line after only 124 mm of irrigation and was poorly fit by the one-dimensional convective-dispersive equation (CDE). On the other hand, the one-dimensional CDE fit the main PFBA breakthrough pattern almost perfectly, suggesting the PFBA transport was dominated by matrix flow. Furthermore, after 225 mm of water had been applied, less than 2% of the applied PFBA had been leached through the soil compared with more than 59% of the applied Br. This study demonstrates that the methodology of applying a narrow strip of chemical to a tile drain facility is appropriate for quantifying chemical fluxes at the small-field scale and also suggests that there may be a critical input flux whereby preferential flow is initiated.

Agriculture↗