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Biomedical subjects

B L Smith

Publications and source records attributed to B L Smith.

At least 217 records · Page 12Linked to original sources
PubMed1987

Temporal characteristics of the speech of normal elderly adults.

A number of physical and psychological changes occur as a result of the normal aging process. These changes often result in an increase in the time subjects require to perform various motor (and sensory) tasks. Although the effects of aging upon a variety of behaviors have been quite well documented, considerably less information is available concerning how normal aging may affect speech production. The present study examined temporal characteristics of the speech of 10 normal, elderly adults and 10 young adults who produced a variety of words and sentences at both normal and fast speaking rates. Acoustic analyses indicated that the elderly adults' segment, syllable, and sentence durations were 20 to 25% longer than those of the young adults at both the normal and the fast rates of speech. In addition to comparisons that were made between these two groups of subjects, comparisons were also made with durations of the speech of young children studied in previous research. It was observed that the elderly subjects tended to produce durations comparable to those of 6- and 7-year-old children.

Adult↗
PubMed1987

Effects of rate and bite block manipulations on kinematic characteristics of children's speech.

The purpose of the present study was to investigate kinematic characteristics of the speech of children and adults under three speaking conditions. The effects of requiring subjects to produce speech stimuli were studied as they spoke: in a normal manner; at a faster than normal rate; and while holding a bite block between their molars to restrict mandibular movement. Using a strain gauge monitoring system, superior-inferior lip and jaw movement data were collected from 24 subjects--six in each of three groups of normally developing children and an adult control group. For the normal condition, it was found that net peak velocity (i.e., the sum of the peak velocities of the individual articulators) was quite comparable among the three groups of children and the adults. Net peak velocity increased significantly for all four groups of subjects when they spoke at a fast rate, but it did not increase significantly in the bite block condition. For most measures, there were typically no differences in peak velocity across the various speaking conditions when comparing the three groups of children to one another. In general, articulatory displacement data showed patterns quite similar to those of the peak velocity data. In addition to the displacement and peak velocity data, pilot data are discussed concerning temporal properties of articulatory phases and also concerning maximum, nonspeech articulatory gestures.

Adult↗
PubMed1987

An investigation of motor equivalence in the speech of children and adults.

Although the concept of motor equivalence (i.e., articulatory intercoordination) is generally accepted as functioning in normal speech production, few studies have experimentally demonstrated its existence. One purpose of the present study was thus to obtain additional data concerning this phenomenon. Because motor equivalence is often assumed to represent a rather sophisticated ability in speakers, another purpose of the study was to determine whether trends could be observed that might demonstrate a developmental progression toward more frequent occurrence of articulatory intercoordination with increasing age. A strain gauge transduction system was used to monitor inferior-superior upper lip, lower lip, and jaw movements produced by a group of adults and three groups of children ranging from 4-11 years of age, as they spoke in a normal condition and in two "perturbed" conditions (bite block and fast rate). Based on the assumption that the presence of a significant negative correlation between two articulators constitutes evidence of articulatory intercoordination, there was little indication of motor equivalence in the speech of the adults or the children.

Adult↗
PubMed1987

Effects of bite block speech on intrinsic segment duration.

The fact that low vowels tend to have longer intrinsic duration than high vowels is sometimes attributed to mechanical characteristics associated with the greater distance the jaw travels in producing low vowels. To investigate this tendency, 6 adult speakers of English each produced 72 [h]-vowel-consonant stimuli containing high and low vowels under 'normal' conditions and with their jaw fixed. If duration differences commonly observed between high and low vowels are a result of only mechanical effects of mandibular movement, it was hypothesized that stabilizing the jaw would eliminate these intrinsic vowel duration differences. Based on acoustic measurements that were made, it was found that the fixed-jaw conditions affected the intrinsic durational differences between high and low vowels to some extent, but the contrast was not entirely removed. In addition to the vowel duration changes, a number of systematic effects upon consonant closure duration were also observed as a result of the normal versus fixed-jaw conditions.

Humans↗
PubMed1987

Kinematic characteristics of postvocalic labial stop consonants produced by children and adults.

It has been commonly observed in the speech of English-speaking adults and children that vowels are longer when they precede voiced versus voiceless final obstruents. However, less is known about articulatory characteristics of such productions, particularly in the case of children. The present study investigated kinematic properties of children's and adults' productions of labial stop consonants in postvocalic position. Acoustic measures of the same segments were also obtained. It was observed that for all three groups of children and the adults, closing gestures into [p] occurred more rapidly than did closing gestures into [b]; however, there was a tendency for the difference between [p] and [b] closing velocities to increase with age. Possible relationships between acoustic and kinematic factors were also explored.

Adult↗
PubMed1987

Excretion and transformation of [14C] penitrem mycotoxins in sheep bile.

[14C] penitrem A (1.1 mg) was given intravenously to a sheep under barbiturate anaesthesia. The radioactivity was almost completely excreted in the bile within four hours but the penitrem had been transformed to more polar products. [14C] penitrem E (4.5 mg) was eliminated similarly. Incubation of the penitrems with sheep or rat liver homogenate did not result in any metabolic products. However, in sheep bile, whether previously boiled or not, complete transformation to more polar products occurred spontaneously within seven hours at 37 degrees C, and apparently non-enzymic process which seems to be a novel attribute of bile.

Animals↗
PubMed1986

Arterial embolectomy: a 34-year experience with 400 cases.

A series of 400 peripheral arterial embolectomies performed in 326 patients over a 34-year period is presented. Operative mortality was 11.0 per cent overall and 10.0 per cent in patients after the introduction and use of Fogarty catheters. The plateau in mortality is related to the association with serious underlying cardiac disease. The amputation rate was 9.5 per cent, with a corresponding 90.5 per cent limb salvage rate. Cardiac disease was the most common cause of emboli and was responsible for the majority of deaths. Mortality was considerably higher in patients with aortic and iliac emboli and in patients with recent myocardial infarcts. Amputation rates were higher with femoral and popliteal emboli and correlated directly with the time delay from onset of symptoms to performance of embolectomy. Higher amputation rates in the second half of the series are related to liberalization of the indications for embolectomy. Prompt operative management of patients with peripheral arterial emboli remains the treatment of choice. Low mortality and amputation rates can be achieved with early embolectomy and routine use of heparin.

Adolescent↗
PubMed1986

A comparison of temporal measures of speech using spectrograms and digital oscillograms.

To determine whether any systematic differences occur as a result of using spectrograms versus digital oscillograms to make durational measurements, a number of temporal features (e.g., voice onset time, vowel duration, and consonant closure duration) for 3 speakers were independently measured by 2 different investigators. Both experimenters measured the same intervals with conventional spectrograms and with digital oscillograms, separated by at least a 2-week interval. Oscillograms tended to reveal slightly longer vowel durations and more voicing during consonant closure, while spectrograms evidenced slightly longer consonant closure durations. In general, variations between the two types of instrumentation were no more than 8 to 10 ms and are, therefore, of primary consequence only for studies in which quite small temporal differences are critical.

Adult↗
PubMed1986

Persistent sciatic artery and vein: an unusual case.

Persistent sciatic artery is a rare anomaly that has been reported in 48 patients in the North American literature. No report has contained more than two cases. This article discusses the first reported case of bilateral persistent sciatic arteries in a patient who also has normally developed superficial femoral arteries. This unique situation allowed removal of the superficial femoral artery for a malignant femoral nerve schwannoma without a concomitant reconstructive arterial procedure. A similar anomaly of the venous system permitted the operation to be done without compromising venous outflow.

Adult↗
PubMed1986

Uniformity of response of identical twin cattle to sporidesmin intoxication.

Sixteen pairs of identical twin dairy calves were reared together and at one year of age subjected to a test of uniformity of response to sporidesmin intoxication. The response was measured by scoring livers for toxic injury and by measuring serum gamma-glutamyltransferase at weekly intervals after dosing. Within pair variance in serum gamma-glutamyltransferase was greatest at two and six weeks after sporidesmin dosing when enzyme levels were rising and falling. Within twin variance and the interclass correlation coefficients were least and greatest respectively at five weeks after dosing. At five weeks the GGT correlation coefficient was 0.89 and for liver injury score 0.76. High consistency among twins of a pair, compared with differences among pairs indicates a high relative efficiency in using identical twins rather than singles for experimental work (approximately x 5). It is also consistent with a high heritability of resistance to sporidesmin intoxication in dairy cattle.

Journal Article↗
PubMed1986

Articulatory movement characteristics of labial consonant productions by children and adults.

One purpose of the present investigation was to attempt to better understand articulatory movement characteristics of children's speech, particularly as they might relate to the question of why acoustic measures of children's segment durations are often longer than those of adults. In order to address this issue and to consider other general characteristics of children's speech production development, a variety of data was obtained from three groups of children and from a group of adults using strain gauge instrumentation to monitor superior-inferior lip and jaw displacement and peak velocity. Results indicate that the children's peak velocity and articulatory displacement measures were in many respects quite similar to those of the adults, although certain differences were observed. For a number of measures, there were also few peak velocity or displacement differences observed among the three age groups of children, despite the fact that they spanned about a six-year age range. In general, it appears that even when children and adults produce consonant sounds that are perceptually "correct," articulatory differences can be observed among their productions.

Adult↗
PubMed1986

Successful treatment and prevention of murine Pneumocystis carinii pneumonitis with 4,4'-sulfonylbisformanilide.

Pneumocystis carinii pneumonitis was prevented in 0, 50, 100, and 100% of immunosuppressed rats given doses of 0.5, 5.0, 25.0, and 125.0 mg/kg (body weight) per day, respectively, of 4,4'-sulfonylbisformanilide (DFD). Therapeutic efficacy was demonstrated with DFD at 25.0 mg/kg per day, and when this dose was combined with trimethoprim, the combination was as effective as trimethoprim-sulfamethoxazole, which has been proven to be effective in the treatment of murine and human P. carinii pneumonitis.

Animals↗
PubMed1986

Use of symptoms by schizophrenics to monitor and regulate their illness.

Interviews with 62 outpatients with chronic schizophrenia and schizoaffective disorder indicated that many patients monitor symptoms that they associate with changes in their illness and alter their behavior based on their symptoms. Ninety-eight percent of the subjects identified symptoms, two-thirds of which were nonpsychotic, that indicated to them they were getting worse. Eighty-two percent of those who identified symptoms of decompensation responded by altering their behavior, either by self-treatment (such as self-medicating, engaging in a diversionary activity, or attempting to ignore the symptoms), by seeking mental health assistance, or both. The authors compare their findings with those of other studies and discuss the study's implications for research on and care of schizophrenic patients.

Adult↗
PubMed1985

Genetic analysis of tumorigenesis: XXI. Suppressor genes in CHEF cells.

In previous studies, fusions of transformed X nontransformed CHEF cells have produced hybrids that were suppressed for transformed traits and for tumor formation. During subsequent growth, the suppressed phenotypes were lost coincident with chromosome loss, and in one study the loss of anchorage dependence was correlated with loss of chromosome 1. In this paper, suppression of serum and anchorage requirements for growth is examined with the use of double-mutant tester stocks. Nontumorigenic low serum mutants from CHEF/18 cells are shown to complement with the lowered serum requirement of CHEF/16, a tumorigenic line, indicating that the high serum requirement is dominant and regulated by at least two genes. Similar results were previously reported for the anchorage requirement. Suppression of the two traits is found to segregate independently in hybrid subclones with reduced chromosome numbers, showing that different genes control suppression of the serum and anchorage requirements. Evidence for two modes of suppression, by dominant alleles of transformation genes and by unrelated genes, is presented and discussed.

Animals↗